Exploding Torqueflites

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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
 
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?
 
briankaplan said:
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
Click to expand...

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.
 
agrevbuzz said:
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??
Click to expand...


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??
 
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.
 
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 $$$$.
 
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