Exploding Torqueflites

Why it happens, and how to prevent it from happening to YOU!
http://andrewsracingtrans.com/Images/carnage/exploded001.jpg

A few years back at a local dragstrip, I happened to be standing by the starting line when a racer in a 66 Dodge had his 727 explode right off of the starting line.

I went to his pit area to examine the carnage, there was a massive crater in the floorboard/transmission tunnel area. Luckily the racer only suffered from a sore ankle. We were discussing the possible causes, when he told me he broke the ring gear in the differential the week before. He mentioned that his "transmission guy" checked out the transmission afterwards and gave him the OK to put the car back together. To my surprise the "transmission guy" was standing in the racer's pit area. I told him that these transmissions are not supposed to explode if they are built with quality components and the correct techniques. He didn't take kindly to me offering up my opinion at the time, and he simply replied "If you race enough it will happen". That statement is flat-out WRONG.

Why it happens:

It all starts when the over-running clutch (aka the sprag) in the rear of the transmission case is damaged. The roller bearings will commonly "roll-over" the posts or fingers on the spring retainer. This action will cause the transmission's geartrain to over-rev the engine rpm multiplied by the first gear ratio, commonly 12,000 rpm or more. The stock OEM powered forged high gear/front clutch drum retainer will explode at approximately 9,000 rpm. The sprag can be damaged by one or more of the following:

1) Driveline failure such as:
-Broken ring and pinion
-Broken u-joint or u-joint straps
-Broken driveshaft
-Broken axle shaft
-If you have a driveline failure, remove the transmission and carefully inspect the case and tail shaft area for cracks. Disasemble the transmission and check the sprag in the back of the transmission case. If it is not damaged, it is recommended to replace the springs and rollers to be on the safe side.

2) Using a reverse manual or trans brake valve-body that does not apply the low/reverse band in first gear.
-Ask the manufacturer of your valve body if it has the low bandy apply feature. This is very important, and I blame the majority of transmission explosions on valve bodies that are not applying the low/reverse band in first. If your car "free wheels" in first (early turbo action valve bodies), it is not applying the low/reverse band.

3) Misuse/abuse on the street or strip in first gear.
-Remember you can only damage the sprag in 1st gear. Start your burnout in 2nd, and shift to 3rd. When on the street, repetitively getting in and out of the throttle while in 1st gear can damage the sprag.
http://andrewsracingtrans.com/Images/carnage/bent_fingers.jpg
In the photo above notice the two bent fingers on the spring retainer.
http://andrewsracingtrans.com/Images/carnage/willie_b.jpg
Photo courtesy of www.kbpi.com
http://andrewsracingtrans.com/Images/carnage/willie_b_003.jpg
Photo courtesy of www.kbpi.com

How to prevent this:

You can virtually eliminate the chances of having an explosion by using a valve-body that applies the low/reverse band in first gear. By having the low/reverse band applied in first, the band helps to "cushion" and protect the delicate sprag. Remember with low band apply, the engine will compression brake when the selector is moved from 2nd to 1st, so make sure your speed is substantially lower prior to shifting down to first.

It is also a good idea to replace the OEM powder forged high gear/front clutch retainer drum with a billet steel drum for the street, or a billet aluminum drum for "race only" vehicles. Although the aluminum drum is made from strong 7075 material it is not recommend for street use as it will wear quicker.

A bolt in sprag is a common upgrade for the racer's peace of mind. It will not, however prevent a transmission explosion. I would recommend the "Ultimate" sprag as an upgrade from the previous 4 bolt, 12 roller design. The "Ultimate" sprag is a 6 bolt, 16 roller design, with 4 extra springs and rollers to provide that much more sprag protection.
http://andrewsracingtrans.com/Images/Advertising_graphics/727_images/ultimat_6.jpg
6 bolt, 16 roller design "Ultimate" sprag

Finally, all race cars should use a SFI approved transmission scatter shield to prevent debris from entering the vehicle should you have an explosion.

If you have any questions regarding this very important topic, please by all means feel free to reply here, PM me on the board, send me an e-mail or call me at 720-939-4896.

Thanks for reading,

Chris Andrews

Great thread. I'm gonna more this to the Tech Archive (in a week or 2)after everyone has a chance to read it. :thumrigh:

Chris I see A&A offer 2 differant reverse patern valve bodies 1 race and 1 street whats the differance ?

WOW that looks just like the trans. when i blew it up in a 67 Coronet i had about 10 years ago.
Never figured why it exploded,so i just threw it on the scrap pile.

Chris I see A&A offer 2 differant reverse patern valve bodies 1 race and 1 street whats the differance ?

Hi Adam,

They are basically the same as far as pressures and shift firmness on the upshifts. But the Street version has a softer 2-1 downshift, while the Race version does not.

Both valve bodies require a billet Low/Reverse piston kit as well. The stock pistons can crack with the increased line pressures.

Chris

That's what took off part of Big Daddy's foot too, right? Or was that a motor explosion?

I saw one of those blow up first hand, once. That's why I've got a big ol' blanket on my tranny.

And yeah, I know, I've got the wrong valve body. But I'm sticking with it for now.

sooooo....
i have a 400 with a .509 cam, edelbrock torker intake, will have 3.91s and a 3000-ish stall converter soon.....i don't know what EXACTLY the tranny is...whether old stocker, rebuilt, or what.....

guess that's bad?????

also, how good are the TCI or Mancini trannies???

i was kinda looking at the tci competition ($850) and puting a manual/auto valve body in it....

sooooo....
i have a 400 with a .509 cam, edelbrock torker intake, will have 3.91s and a 3000-ish stall converter soon.....i don't know what EXACTLY the tranny is...whether old stocker, rebuilt, or what.....

guess that's bad?????

also, how good are the TCI or Mancini trannies???

i was kinda looking at the tci competition ($850) and puting a manual/auto valve body in it....

Well, I don't know if it is bad, but it wouldn't be a bad idea to crack it open and see what's inside. :mrgreen:

I really couldn't comment on the quality of a TCI or Mancini transmission, as I have never used either of them. I am pretty sure that Mancini sells a lot of turbo action stuff, which could mean they are still selling reverse manual valve-bodies that are NOT applying the low/reverse band in 1st. I did hear that Ron Mancini started his "own line" of transmissions.

Are you looking to maintain the forward pattern valve body, or are you looking to use a reverse pattern?

Let me know if you have any other questions!

Chris

i already have a TCI forward pattern shifter....that would be one more thing to change out if i wentto a reverse pattern....also, i think a reverse pattern would be more suited to a strip car, and mine is more of a street car that will hopefully be in the low 11s someday.......

Very good article, Chris. I have a Cheetah manual valve body in my 727. Don't know if it has the low band apply or not. I read somewhere that it alot safer to start your burnout in 2nd gear and then throw 3rd, and that's what I've always done. Does this alleviate the potential for disaster? Thanks.

Very good article, Chris. I have a Cheetah manual valve body in my 727. Don't know if it has the low band apply or not. I read somewhere that it alot safer to start your burnout in 2nd gear and then throw 3rd, and that's what I've always done. Does this alleviate the potential for disaster? Thanks.

Hi Dan,

I am positive that your turbo action reverse manual valve body is not applying the L/R band in 1st. However, you're doing everything right as far as your burnout goes; start in 2nd and shift to 3rd.

You would still practice the same burn out technique with a valve body that is applying the L/R band in 1st. The low band apply valve body will decrease your chance of having a sprag failure and possible transmission explosion.

With the valve bodies that aren't applying the L/R band in 1st, the sprag is very venerable, presenting a greater chance of damaging the sprag because the low/reverse band and drum are not "cushioning" the sprag.

"We must protect our delicate sprag" :salut:

the pics are right dont do burn outs at drags in 1st gear. i have seen this first hand

I had a fErd a couple years ago, that was all Mopar running gear, including the front suspension (a '56 HT). The BB 383, had a 727 Auto, with "B&M" components, I was told.

The reverse valve body worked well. If I kept the trans. in 1st gear, accelerated a little, the trans. would "glide" when I took my foot off the accelerator (the only way I can describe it) as if I'd put the transmission in neutral, but, if I used the throttle a little, to bring it up to speed (what would be the equivalent to the road speed) the trans would engage normally. Was this the reverse valve body, or something else in the transmission.

The reason I'm asking, I'm building a 392 Hemi Dart, and have several options for transmissions. I really liked the feature in that combination described above, and if I could duplicate it with this car, I think the small block 727 would be my choice. I'm not a transmission guy at all, never had an automatic apart, but I guess there's a first time for everything.

Please enlighten me..! :argue:
Bob

Thats the lack of low band apply. Its like the tranny is in nuetral when you let off of the gas in 1st gear. A valve body that applies the band in low will decelerate when letting off of the gas and is much safer.

A reverse manual valve body will have the shift patern reversed. Instead of PRN321 it will be PRN123. This will keep you from hitting Par reverse or Nuetral while shifting threw the gears.

Chris:
I have a slightly heated up 360, probably 360 HP, in a 66 Dart, 3:23 gears, and for the past 15 years I've run a 727 in it. Prior to that I ran a 904, and this time I think I want to go back to the 904 again. This is a 99% street driven car, with maybe 1 or 2 trips per year to the strip. Is there any advantage in going to a manual or reverse manual valve body for this application, and if so, which one? Also, does the manual valve body negate the need for the kickdown linkage, which is always a PITA on these small A Bodies. If I understand correctly, some still need the linkage and some don't.
Thanks.

Sid

Low reverse band apply is nice. I have been running TA valve bodies since the 70's without the low reverse band apply and have always been careful enough to never have a problem. I also taught my son how to drive his street car with one on the street as I have driven a street car without the L/R band apply on the street since 1997. I build my own transmissions and have always been careful. And I like the quality of Turbo Action parts but I too will be getting a L/R apply next time I have to buy a valve body. Ron

I agree with ron. I also run a T/A valve body but would like to swwitch to a low band apply unit. Chris likes the A@A valve body best. I hear thw griners are also good but I think the line pressure is very high on them. You wont need the kick down linkage with a manual valve body. I think the old B@M kit says you can use it to soften the shifts though.

Thanks for the info guys. One more thing to put on the list of parts. :)

My Dart has a TA valve body, what benefits are there in using a VB without low band apply
Mike

I dont think there is any bennefits of not applying the band. I think it was done to make shifts faster origanally

It's a matter of shift timing. Without the L/R band apply the only thing needed to shift to second gear is to apply the front band. If you have the L/R band applied then you have to release that band and apply the front band to achieve the 1-2 shift.

This is why the T/Flites never shifted 2-3 very well because they have to release the front band and apply the front clutch to effect the shift.

Timing two events to happen at the same time is much harder than just making one event happen.

I saw a SS/BA Hemi Belvedere gernade a trans. at the Cajan Nationals back in 76. One big fire ball in the burnout box. Wow, that was not pretty. The driver got 3rd degree burns on his legs. If you ever see it happen you will never forget it.

Great info guys, I am staring to rebuild a 73 727 and am wondering if all stock valve bodies had l/r apply. If not is there any way to tell with the trans out? Also if it does have l/r apply, will installing a shift kit affect it? Thanks for any help...

[B]Chris.........
Nice article.

Great info guys, I am staring to rebuild a 73 727 and am wondering if all stock valve bodies had l/r apply. If not is there any way to tell with the trans out? Also if it does have l/r apply, will installing a shift kit affect it? Thanks for any help...

Sorry for the delayed response, I just noticed these newer posts.

Your stock valve body applies the L/R band in Manual Low. It does not apply the low/reverse band in Drive Low. Meaning, if you're in Drive, and the transmission is shifting by itself, when you accelerate from a standing stop with the shifter in the D posistion, the L/R is not applied allowing the possibilty of a sprag failure. When you are in manual low, with the shifter in the 1 posistion, the L/R band IS applied.

Installing a shift kit will not affect this...

HTH's....

[B]Chris.........
Nice article.

:salut:

Crap!!! I just bougt a Turbo Action Cheetah reverse manual valvebody... I should have read this thread first :sad1:

hey chris,
just a question or 2 on the sprag you mentioned. i just had a trans done with a 4 bolt. this has me concerned, whether i should have it all torn apart again and go to a (6). would you say a 4 bolt is not good enough, or is there a way to get along with it? i`m not a serious weekend racer. only once in a while, i like to go out and i don`t use slicks, just real wide tires. i don`t know, should tell you more about the car? maybe 600 hp,3800 stall and also, i have a csr shield. i hope i gave you enough on it to get an idea and thanks so much for your time. thanks again, gene in jersey

Hi OiiiiiiO,

You must be a jeeper with that username? :)

The 4 or 6 bolt is not going to make any significant difference. It's more of the upgrade in rollers from 12 to 16 when going from a conventional sprag to the "Ultimate" sprag. I wouldn't worry too much if I were you. If the transmission was assembled correctly, with good parts, you'll be fine.
:thumbup:

Just a quick question, How do you start your burnout in second gear without a manual valve body? Or once you put it 2 it doesn't start off on first?

There is another area of concern in the TF series of transmissions. The original (old) cast iron drum is prone to blowing up. If the board administrator gives me permission, I'll post the website of the company I work for and give further information on this problem. We have on our website, the results of testing we had done on an original cast iron drum and the ones we manufacture.
transman

Welcome aboard. Feel free to post your info.

So if when I broke my front U joint. My rev limiter helped to
prevent this in my trans. I had a 7000rpm limiter in my MSD box.
I took the trans out. But have not gone through it yet.
Anybodys input? Thanks Brian aka GreenDuster

Thank you for your permission to post this site where I work.

The company I work for has a website www.tcsproducts.com

We manufacture a wide variety of products for automatic transmissions. Our present test mule is a 2007 Jerry Haas GTO, running Steve Schmidt power (around 1300HP), and are using a 727 transmission with custom built 904compnents. The car is a legit BA/A car that runs in the low 7's and around the 190+ mark. It recently reset the index for BA/A.

On the site, look for transmissions, and then look for the Torqflite button. There you will find the information as to when the front drum of a 727 comes apart. This was done by an independent company, not ourselves.

transman

Excuse my ignorance for a moment, is this a manual or automatic transmission this is happening to. I ask, because I had a differential go out on me with my dart while I was driving. Do I need to worry about my automatic tranny too??

The Question.... I still have (while following this long term thread) and not really being a tranny guy. IS..... What, if any, are the differences between the 727 and 904 Sprag(s) ? I have never seen a HD 904 sprag.. Why?

727 outer hubs are pressed into the case. 904s are either bolted or riveted.

So if when I broke my front U joint. My rev limiter helped to
prevent this in my trans. I had a 7000rpm limiter in my MSD box.
I took the trans out. But have not gone through it yet.
Anybodys input? Thanks Brian aka GreenDuster

The rev limiter helped to not overspeed the engine, however if your car was in first gear the trans already was. Take it apart and carefully inspect the over running clutch for signs of cracks, and flat spots on the rollers and race, springs that are deformed and spring tabs that are bent.

Excuse my ignorance for a moment, is this a manual or automatic transmission this is happening to. I ask, because I had a differential go out on me with my dart while I was driving. Do I need to worry about my automatic tranny too??


Yes TorqueFlites are automatic transmissions. If your car was in first gear I'd suggest you take it apart and inspect the over running clutch as per the previous post.

Alright sooo...if you can damage the sprag by doing a burnout in 1st....then couldnt you damage it leaving the lights in 1st gear also??

anybody anybody??

no its different with a load instead of freespooling in the water box

FROM a guy who has done his fair-share of TFs in the past(albeit IN the distant past - I know nothing about the 518 etc) .....

ISN'T the problem the "fragile" front drum. Someone mentioned that this stock drum was cast iron. Unless they have changed this ...I thought that it was a "splintered iron". Which is a porous "cast iron" type material. Correct me if I am UNcorrect.

Now to the "problem" at hand. WOULDN'T just running a simple alum front drum totally eliminate any "exploding TF's" ? From what I remember - the alum drum is tested to well-over 16,000 rpms.

Yes, the sintered iron front drum is a problem, but only when the sprag has been damaged. A damaged sprag is the root of the problem. Once damaged, the sprag can allow the transmission to overspeed. The overspeed condition can cause the OEM drum to fail, hence your explosion. And yes, an aluminum drum will remedy the problem, but it is prone to premature wear in street driven applications. The aluminum drum is ideal for race applications, but in street use, the constant action of front band apply/release will wear the friction surface much faster than a steel drum.

When having your trans rebuilt or freshened, ask your rebuilder about this. If he doesn't understand this basic theory, you should probably start looking for another guy.

DOESN'T the vehicle weight have lots to do with the band wear rates ? .. and isn't the quality of the 1-2 shift improved with the alum drum ? .. due to the lighter weight?

And aren't there more wear-issues and concerns with the sealing rings on the reaction shaft than on the band surface?

Sealing ring wear is indeed a concern, but it is band wear that is more detrimental to an aluminum drum. The effects of shift timing and line pressure have more influence on band wear than does vehicle weight. Drum weight, along with shift timing and line pressure, all effect the quality of the 1-2 upshift.

Are you running an alum drum in your Duster ?

The Duster is an 11.50 street/strip car. 1.58 sixty foot times. 727 Torqueflite with an OEM front drum and a six bolt sprag that gets replaced during every freshening of the trans. And I do use a non-freewheeling, band apply reverse manual valve body, along with a Kevlar band.

A 6 bolt sprag ..... why ? ... have you ever seen the outer part of the sprag spin in-the-case ?? How many TFs have you "done" ?

A friend of mine that used to work for Mopar & still does alot of trannys in his own shop said a steel drum would be best in theory but costly. At his suggestion I began looking for on. As I recall Coan has one but it's big $$$$.

The place in Canada(TCS?) offers one ... and I think that it is about the same $$$ as the alum one.

sooooo....
i have a 400 with a .509 cam, edelbrock torker intake, will have 3.91s and a 3000-ish stall converter soon.....i don't know what EXACTLY the tranny is...whether old stocker, rebuilt, or what.....

guess that's bad?????

also, how good are the TCI or Mancini trannies???

i was kinda looking at the tci competition ($850) and puting a manual/auto valve body in it.... dunno bout Mancinis but TCIs reputation for 727s is junk

Maybe I missed something... If you have a stock valve body, when the shifter is in manual low the L/R band is applied. When the shifter is in automatic low the L/R band is not applied. Right? Then why wouldn't you always want to start in manual low regardless of whether it was a burnout or a launch? If you start a burnout in manual 2nd... the trans is starting in 1st gear non L/R applied. Like I said, maybe I missed something, please help me out here and explain further.

When you start out in manual 2nd, the trans is starting out in 2nd gear. The problem occurs when you come out of the throttle and the tires hook hard. Like driving out of the water, and lifting just as the tires bite. This places severe loading on the rollers, and the entire sprag, as well as the case. This is when breakage usually occurs.

I don't know much about auto trannies, so I can only speak generally.
The guy who built the 727's for our Stock Eliminator car (and many previous for my partner), would "pin the sprag" if I remember the terminology correctly. There was never a problem. (Even after breaking a ring & pinion.) I hope this was a good fix and we weren't just lucky. But, there were hundred's of runs on many different trannies.

I was pretty rough with a built slant 6 and modified 904 with the 999,998 gears and B & M shift kit. When all was done I had nothing but reverse, neutral and some scary look metal splinters from the f drum.
I have not used B&M shift kits since, though I don't blame them, I have not had this problem ever since.

Gee, nobody mentioned the NO NEUTRAL DROPS as another way of avoiding the dreaded Exploding Torqueflite experience. Maybe everybody has gotten the message.

Actually thats how I broke the first one, never again.
But hey If you don't break something once in a while your not learning.

Good information here. Not to Hyjack the tread but, I have an Art Carr reverse Manual valve body, it has been in three transmissions so far and in every one of the trannys it locks up between 1st and 2nd gear. I have had several people look at it, but so far no one has been able to fix it. the dang thing will darn near throw you thru the windshield. Any ideas would be greatly appreciated.

I Have A 72 Dart That Run 6.90s In 1/8 Mi. 1.46 60 Ft. Times, About 6 Weeks Ago I Broke A Rear U Jt. On Staring Line. When I Bought Car I Didn't Ck U Jts, They Were Jts, With Greece Zerks, They Are Hollow, And Weeker Than Sold Jts, I Put A New Joint In Rear And Didn't Ck Trans For Damage Went Back To Track Made 6 More Runs Noticed A Trans Leak, Thank God I Then Checked Trans It Was Cracked All The Way Around The Frt Of Pump . Only 2 Inces Remained In Tack. Could Of Realey Done Some Serious Damage To Car And Myself. Replaced Case. And Went To Aluim Drive Shaft With Solid Brut Jts. I Had The Local Performance Trans Man Change Case And Check All Parts . So Check Ck Trans Often. My Trans Is A 904 They Are About 80 Lbs Lighter Than 727. If Built Right They Can Handle 5 To 600 Hp. If You Use A 998 Or 999 Case They Are Stroger Yet, And Have A Extra Clutch Plt And Wider Band. Good Luck Gary!

i did not think a 904 or a 727 did not bloe up couse of runin it hard i thought they could bloe up only if u NEUTRAL DROPed it i just put a tci 904 in my duster with a 3500 stall behind a built 360 if any one knows if tci trans uses the 6 bolt 16 roller sprag id like to know its not a manule vavle body but will handle 450 hp thanks tom

Not all "race versions" are alike. Read Chris's article. Depends on the builder. If yours does not have the L/R band apply you are susceptible. 727's can explode. I've seen it.

while the Race version does not.

Back in the days a buddy of mine had a volare wagon that needed a brake job BADDDDD....the pads eventually ground into the cooling fins of the rotors (this sounded BRUTAL) So a few days later he stops over picks me up and we're heading to McDonalds or somewhere pullin up to the first stop,doin about 30 mph,I ask didja ever fix dem brakes ,He says yeah... throws it in reverse and punches it!!!He drove around for about two weeks using "the reverse drop technique with no trans failures before he finally did a brake job!!!Love them 727's...

Ok My First Concern Here Is Safety I Have A A 727 That I Build Blue Plate Clutches Full Manual Valve Body Everything Else Is Basicaly Stock...and Everything Has Been Working Fine But Now I Am Concernced.... I Figure I Will Run It Till It Blows Witch Is Probably Stupid But What Measures Can I Take Whats Better Blanket Or Shield.. And It Seems That It Is Theis Sprag That Is The Problem Mainly Worth It To Pull It All Apart And Replace It??

Put a better front drum in it. The front drum on the 727's is what blows to pieces. It can spin at up to 2.5X cranks shaft RPM.

See if your MVB is a low band apply.

I was reading threw all this and theres alot of good info.
I use the new cheetah valve body that has the forward pattern with low band apply.
Also i am installing the newest one (17676 part #)in my cuda.
Cheetah valve bodys are great.
But i have to tell you, i have been doing my burnouts ,starting in 1st gear and then going into second gear and letting off for years and have never had a problem.
This dosen't mean that there might not be a better way of doing your burnout and it makes me wonder??
I would think, it would be harder on the clutch pack?
ANYWAYS\\\\\\\\

Two guy's asked if they have a stock valve body ,how could they start there burnout in second gear and the answer is, YOU CANNOT START IN SECOND GEAR WITH A STOCK VALVE BODY\\IT WILL STILL START IN 1ST GEAR.
You may put the selector in the second gear position but the transmission will still start in 1st gear and then go to second.
YOU NEED A MANUAL VALVE BODY TO DO THIS. :hello2:

727 needs a billet front drum....

so far i have not seen 904 drum come apart....probably cause there mass is alot smaller.

I had a fErd a couple years ago, that was all Mopar running gear, including the front suspension (a '56 HT). The BB 383, had a 727 Auto, with "B&M" components, I was told.

The reverse valve body worked well. If I kept the trans. in 1st gear, accelerated a little, the trans. would "glide" when I took my foot off the accelerator (the only way I can describe it) as if I'd put the transmission in neutral, but, if I used the throttle a little, to bring it up to speed (what would be the equivalent to the road speed) the trans would engage normally. Was this the reverse valve body, or something else in the transmission.

The reason I'm asking, I'm building a 392 Hemi Dart, and have several options for transmissions. I really liked the feature in that combination described above, and if I could duplicate it with this car, I think the small block 727 would be my choice. I'm not a transmission guy at all, never had an automatic apart, but I guess there's a first time for everything.

Please enlighten me..! :argue:
Bob

I had a 1970 GTX with a 440 b&m trans and 9" 4200 stall converter do that, I could criuse in first gear to about 30mph, then let off gas pedal and rev it some while still rolling, kinda fun.:read2:, boy the old street racing days, the 80's were fun:cheers:

I just had a 904 built for racing with parts advise from Chris Andrews.Changed front drum,red racing belts,lower 1st gear etc...also ordered a 4500 stall from Coan.Yet to be tested.

Thanks for advise Chris!:toothy10:

P.S Blanket or shield?????Which one is better?Thanks.

I just ordered a B&M TransPak kit for my 727. I then started to wonder if this could interfere with the L/R band and cause it stop working. It is the stock forward valve body, should I have any problems with it? Thanks for any replies 8)

I just had a 904 built for racing with parts advise from Chris Andrews.Changed front drum,red racing belts,lower 1st gear etc...also ordered a 4500 stall from Coan.Yet to be tested.

Thanks for advise Chris!:toothy10:

P.S Blanket or shield?????Which one is better?Thanks.
No problem, Scott!

Most prefer the shield versus the blanket as the blanket typically does not fit well with headers, etc. It can also hold heat in.


I just ordered a B&M TransPak kit for my 727. I then started to wonder if this could interfere with the L/R band and cause it stop working. It is the stock forward valve body, should I have any problems with it? Thanks for any replies :cool:
You shouldn't have any problems with that shift kit as long as it's installed correctly. Even though your shift kit automatic valve body applies the L/R band in first, caution should STILL be used while you are in first gear because there is a chance you can damage the sprag.

Hey Chris,good to see you stop in.I have yet to try my car/tranny at the track.Just waiting on some Weld wheels for the front(small rims to clear my fenderwell hedders)Next will be the sheild,which shouldn,t be that hard to install seeing I have the fenderwell hedders.I hope?LOL

I am not sure what this guy did ....
but he knows not to do it again............

WoW,that looks like the size of a foot!I wonder how it looks inside the car?

some more pictures

that is messed up. looks like that car is real old school pinto front end w/4 bolt hubs up front .

yup ... I understand it originally had a vega body and was changed to a cuda ... very old school... but it looks neet

How did the driver fair, that looks pretty devastating.

WOW!!!!! :tongue9:

I didn't now the driver untill after this incedent....
he was looking for a lenco when he meet me....
but he said he had a sore foot for a while....


and note the drum (as I was told ) whent threw the shield and the door .... and over the stands at the track

I like my lenco with the " trany blankets "

Yeah, I see where it even hit the door x brace and put a nice dent in the tubing too. Just a sore foot, man that's one lucky dude.

I own page 5.

I am not sure what this guy did ....
but he knows not to do it again............
Really .. you don't???

He damaged the sprag while in first gear causing the transmission geartrain to over-rev exploding the stock high gear drum.

It's very simple, install a billet aluminum or steel direct drum, and a valve body that applies the low/reverse band in first, and you won't have an issue.

Also, don't act like an idiot while in first gear with a 904/727 or any other automatic transmission that uses an over-running clutch. IF YOU GET OUT OF THE GAS WHILE IN FIRST GEAR, AND GET BACK IN THE GAS YOU WILL MORE THAN LIKELY ROLL THE SPRAG AND EXPLODE YOUR STOCK 727 DIRECT DRUM.

If you still feel that you may damage the sprag, keep your transmission out of first gear until you pull it into the stage beams.

I've been building these for ten years with low band apply valve bodies and billet drums. NO EXPLOSIONS TO THIS DAY...

Thank you so much for reading,

Chris Andrews

I dont think there is any bennefits of not applying the band. I think it was done to make shifts faster origanally Hi, The advantage of not applying the band is because you can have an overlap issue from 1st to 2nd. The 1st gear band has to release & 2nd gear band has to apply at exactly the right time to avoid what is called overlap. I used a stock valve body & rebuilt it with a TransGo TF3 kit. The band is on in 1st. I also installed a bolt in SPRAG among other goodies. Works perfect. Steve

I went with a MVB with low band apply and had a full case mod by John Cope, their is s super 8 bolt ultimate sprag I installed, but any of the bolt ins are a must do.

I also run a blanket too, you can still explode, but the band apply os in most cases the best fix.

thanks great write up:)

http://smrtrans.tripod.com/smrtransmissionsintro/index.html

I dont worry about the tranny anymore .

I have his Mega Torqu 727 and his 5000 stall Converter. It has a brake , steel drum , Etc, made by a guy who races mopars. I do my burnouts in second and I lift before I get out of the box.
This tranny shifts great & runs cool. Its in my 499 cu in ,10 second 72 Swinger street/ bracket car.
I got tired of worrying so I bought a good tranny.
I do have a blanket.
I dont like fixing things, especially at the track.

Call Pat @ SMR you will sleep better.

I dont worry about exploding TF727 either...i use 904s....

Not Yet you mean. They are great for Small blocks strokers. Pain for BB install. I would run one for the hp gain but its a hassel for me. I have owned four BB Darts . Three were factorty GTS 383 Cars. I have alot of BB parts or I would go SB stroker. I have been kicking the 408 idea around for my sons duster.

Not Yet you mean.

Never seen a 904 explode..

their drums are very small compared to the 727 ..therefore do not have the mast...

I was rolling through a water puddle at work one day and thought I'd do a "Smoky". Broke the sprag in a heartbeat! Stock 340, Early Turbo Action manual valve body.

I was rolling through a water puddle at work one day and thought I'd do a "Smoky". Broke the sprag in a heartbeat! Stock 340, Early Turbo Action manual valve body.

never do a water burnout in 1st gear........or a least come out of the water in 1st gear....

i think the TA instructions tell ya that...LOL

70, no way a 904 is any safer. You dont see many because not too many mild 904s are being raced in comparison. If a racer has a 904, it's already been beefed up, and most know about the 2nd gear burnout. The geartrain and hydraulic systems are identical in 904s, and the material is the same for the clutch retainer. If the sprage gets rolled, the same issues arise.

I've also heard of them blowing by putting into n at the end of the track(non rev.) I see that Griner makes a clean N after 3 is this a good thing you have to hold the trans brake button to use reverse.

I was at a race track and a 68-69 Cuda with a hemi in it exploded his 727 off the starting line also..

70, no way a 904 is any safer. You dont see many because not too many mild 904s are being raced in comparison. If a racer has a 904, it's already been beefed up, and most know about the 2nd gear burnout. The geartrain and hydraulic systems are identical in 904s, and the material is the same for the clutch retainer. If the sprage gets rolled, the same issues arise.

maybe true...but i have not seen one explode like a 727...same material yes...but the mass of the drum is extremely less...

but then again...what do I know...just a bracket racer...

okay guys where can I get a 6 bolt sprag for a 904 ? and now for the real noob question can I get a valve body that is manual in 1st and 2nd but auto in drive/3rd , would like to be able to burnout in 2nd but still be an auto for daily driving , already ordered the steel drum and 24 spring return module kit and the deluxe racing rebuild kit from TCS here in Canada just need to find the rest before the new motor gets here thanks -Chris

Try Pat Storey @ http://smrtrans.tripod.com/smrtransmissionsintro/index.html (http://smrtrans.tripod.com/smrtransmissionsintro/index.html)

Try Pat Storey @ http://smrtrans.tripod.com/smrtransmissionsintro/index.html (http://smrtrans.tripod.com/smrtransmissionsintro/index.html)
thanks will call him tomorrow

i had a tranny explode like that last year,had parts and oil that came up from floor board,didnt get hurt thatnk god,replaced the tranny,no i have no 1st gera,but i have reverse,2nd,3rd.any ideals,going to check adjustment and drop the pan today

Where can I buy the 16 roller bolt in sprag?
Thank you
joemac1j

Where can I buy the 16 roller bolt in sprag?
Thank you
joemac1j


CRT racing transmissions ... John Cope sells the A+A ... , A+A Transmissions , Coan .

ive heard you can put 904 parts in a 727 is this true

Yes true. We used to do it in Stock and Super Stock. It takes some special parts to do it. You can not just put the 904 internals into a 727 case. Pro Trans in Riverside, California has all the information on this. They also have a straight cut low gear package for the 727. I use it to get my Cordoba 360 of the line.
The reason to use the 904 internals in the 727 was to get that last possible tenth or hundredth when racing in NHRA. This is called "CHEATING". Won some races. Not worth the expense, unless you are racing Stock or Super Stock. However, I'm sure that NHRA is wise to the practice, as they were closing in on it around the early 70's. That is my 2cents. Good luck on your in devours.
joemac1j

heres what happen to me 2 years ago at the line at gateway

That's what took off part of Big Daddy's foot too, right? Or was that a motor explosion?

I saw one of those blow up first hand, once. That's why I've got a big ol' blanket on my tranny.

And yeah, I know, I've got the wrong valve body. But I'm sticking with it for now.

Pretty sure that was a manual tranny flywheel. Which is why there are SFI approved flywheels and explosion-proof bellhousings. I could be wrong, through.

dang this is scary stuff. raced mopars in super-stock for years even built a few racing trans for modified and rails and never had this problem. none of my tranmissions had the low-reverse ban apply. guess it is better to be lucky than good

Use the 3 foot rule...... When you put it in gear.... Roll it 3 feet before you stab it....

yea it comes down to ill only use 1st gear to launch and thats it

BOOM.




Suicide start maybe?

BOOM.
Suicide start maybe?

Now that is a frickinn explosion, converter and all...... Damn

does anyone sell the instructions on how to build the reverse pattern valve body for the o.d. chry. transmission. used to build the 3 speeds when i worked at the dealer in the 60s-70s. one could buy the instructions from chry then. dont know how many i did but it was a bunch. it really isnt hard to do on the 3 speed.