727 Disassembly and Advice

[Austin Spencer]

Took apart my first 727 today, it's a 1978 year out of a truck it says. The guy I got it from said that he worked with TransGo at some point and did some prototyping/early modifications with them, so I was expecting it to be a bit different here or there but there are a few things I was wondering if anyone on here knew about. There's also some general questions about the wear of certain parts, and some rust I found inside.

First for the parts I am concerned about, I've got rust on the Reverse Drum, both inside and outside. Outside has a section that is outside of where the reverse band contacts, and is very rusty, very rough.

There is also some rust on what I believe is the direct drum, but it is fully smooth and just on the surface. It also has 5 clutch rings, which from the video I was watching is 1 more than standard.

Lastly there is rust on the outside of what I believe is the Forward Clutch.

Now for the parts I am confused about. These parts differed from the video I was watching, and seem to be missing parts. First I have the accumulator piston, which was missing the spring on the outside, and had this gear on the inside.

I can't imagine this gear does anything, it just stops the accumulator piston from bottoming in the bore. I've read about people messing with the accumulator piston when the work on the valve body.

Then, my Front Servo was a different style than the one in the video I watched

The one in the video I watched had a much larger diameter spring, and the rod/valve had a whole assembly at the bottom that it was clipped into. Mine had this skinnier spring, and the part I'm holding is all that came out.

The Reverse Band was pretty worn so I'll get both new bands, I have yet to look at the clutch material in the packs. I'll be looking to get a rebuild kit where I can modify what parts I do and don't get for my setup, I believe from a shop in Oregon. Any advice I can get would be great, I am not sure what is and isn't acceptable to work with.

I also have another 727 that I may take apart in order to get some of the parts I am missing here if I need them, but it's hard to know without knowing the exact reasons why each part was modified. The other 727 is a 64 Push Button, but should have the same parts I'm looking for, and hopefully some less rusty parts that I could swap in.

 

[CFD244]

@Duster346

Chris is a great builder and helped me out a bunch. Hopefully he'll chime in. Andrews Racing Transmissions.

 

[Austin Spencer]

One other change I saw was that the inside of my Forward Drum has some cutout for a 3 lobed washer that was on the end of the Forward Planet assembly. I didn't see it in the video I was watching, so I was wondering what sort of difference this was.

 

[CFD244]

Get this book...everyone who has it will agree that it is a must have resource. The author is one of our members @VOETOM

 

[Austin Spencer]

@Duster346

Chris is a great builder and helped me out a bunch. Hopefully he'll chime in. Andrews Racing Transmissions.

Thanks, hopefully He'll be in touch here soon.

Get this book...everyone who has it will agree that it is a must have resource. The author is one of our members @VOETOM

View attachment 1716368009

I've got the book coming right now, just wanted to get the disassembly out of the way first. Looking forward to thumbing through it.

 

[oldkimmer]

Leave your 64 trans under the bench. The rear drum should be replaced but u could have someone with a lathe skim the rust off. I’ve never seen a spacer like that under the acc. I usually use a blocker rod. The front servo is the older style from about 66 to 70. Newer tranny’s use the tri star washer on the output shaft. Likely u have a lock up tranny. Does the input shaft have splines all the way to the end or is the last 3/4 inch necked down and smooth. The front drum with 5 clutches and steels may be the thinner ones. Usually the drum has 4 clutches and steels. Does the rear servo have a spacer in it and a heavier thicker spring? U may be able to sand/soda blast the rust off the other parts or soak them in evaporust. Kim

 

[Duster346]

I've seen some people do some odd things to transmissions over the last three decades or so. I cannot say I've ever seen what looks to be a GM speedometer drive gear put on the accumulator like that. At any rate, you can just discard that and leave the accumulator with no springs or find a spring that goes on top of the accumulator towards the valve body. The spring will slightly cushion the shift, no spring will firm up the shift.

As for the rust I wouldn't be worried about any of that at all. It will blast off in a blast cabinet with glass bead media. Or, as was mentioned you can spin them in a lathe with a scrotchbrite pad.

As for the early '70-back 2nd gear servo, well someone just installed it in favor of the late 5/8" rod single spring servo--for whatever reason, perhaps the original one was worn or damaged. Some folks think the early small rod, two spring servo works better. If you keep the early servo, find an outer spring for it. The old school thinking of removing springs from apply servos is wrong. The whole idea is to get the band off quicker to avoid 2-3 bind or overlap.

I'd not mess with the push button transmission as not much will interchange. That could be a valuable core to someone, and is even more valuable left assembled.

 

[RustyRatRod]

The gear on the servo is a VERY old school trick to use as a blocker for the servo. It firms up shifts some. That is a speedometer drive gear from a transmission output shaft.

 

[volaredon]

What is it that you are calling a "clutch ring"?
I've been inside a few of those tranny's (admittedly not as many as some people have) but enough to know I've never heard of a "clutch ring"

 

[413]

Get the rust and grit out of the trans, use a wore wheel on a bench grinder. do not be haphacpzzard about cleanliness.

Forget the 64 trans, too much different and will just confuse you.

 

[Austin Spencer]

Leave your 64 trans under the bench. The rear drum should be replaced but u could have someone with a lathe skim the rust off. I’ve never seen a spacer like that under the acc. I usually use a blocker rod. The front servo is the older style from about 66 to 70. Newer tranny’s use the tri star washer on the output shaft. Likely u have a lock up tranny. Does the input shaft have splines all the way to the end or is the last 3/4 inch necked down and smooth. The front drum with 5 clutches and steels may be the thinner ones. Usually the drum has 4 clutches and steels. Does the rear servo have a spacer in it and a heavier thicker spring? U may be able to sand/soda blast the rust off the other parts or soak them in evaporust. Kim

I do not have a lockup transmission, it has splines all the way to the end of the shaft. Good to know about the washer though. I'll have to measure the clutches and steels to see what the size is before I order new ones, if I even have to. I'll be taking those apart today to check the life on them. Here is a picture below of my Rear Servo.

I've seen some people do some odd things to transmissions over the last three decades or so. I cannot say I've ever seen what looks to be a GM speedometer drive gear put on the accumulator like that. At any rate, you can just discard that and leave the accumulator with no springs or find a spring that goes on top of the accumulator towards the valve body. The spring will slightly cushion the shift, no spring will firm up the shift.

As for the rust I wouldn't be worried about any of that at all. It will blast off in a blast cabinet with glass bead media. Or, as was mentioned you can spin them in a lathe with a scrotchbrite pad.

As for the early '70-back 2nd gear servo, well someone just installed it in favor of the late 5/8" rod single spring servo--for whatever reason, perhaps the original one was worn or damaged. Some folks think the early small rod, two spring servo works better. If you keep the early servo, find an outer spring for it. The old school thinking of removing springs from apply servos is wrong. The whole idea is to get the band off quicker to avoid 2-3 bind or overlap.

I'd not mess with the push button transmission as not much will interchange. That could be a valuable core to someone, and is even more valuable left assembled.

My application is just going to be a cruiser, nothing crazy, so would you recommend I get a spring for the accumulator or leave it without the spring? I do not have access to a blast cabinet, my work does have a lathe but it hasn't been used in forever, and another member here mentioned just wire wheel, and I do have access to bench grinders with finer wire wheels and scotchbrite wheels. Would those work, or should I stick to a blast cabinet or lathe?

I intend to keep the early servo since I have it right here, no reason to get a whole new part. I'll look online for a spring and see what I can find.

I'll also avoid getting into my 64 push button then. I still have to take it out of my 65 Dart which it was put into at some point, but I'll probably leave it as is.

The gear on the servo is a VERY old school trick to use as a blocker for the servo. It firms up shifts some. That is a speedometer drive gear from a transmission output shaft.

Interesting bit of information there, this trans was supposedly left sitting for 30 years so it could be that someone did that much longer ago and just left it.

What is it that you are calling a "clutch ring"?
I've been inside a few of those tranny's (admittedly not as many as some people have) but enough to know I've never heard of a "clutch ring"

I believe that's a mistake on my end, this is my first transmission teardown so I'm not great with all the names, I just meant the clutch plates.

Get the rust and grit out of the trans, use a wore wheel on a bench grinder. do not be haphacpzzard about cleanliness.

Forget the 64 trans, too much different and will just confuse you.

I'll look into that as an option. I may have the option to use a lathe, but if not I do have access to bench grinders with wire wheel and scotchbrite wheels so I'll look into it.

 

[VOETOM]

If you are in no hurry and have it lying around, soak the rusty parts in Evaporust. It'll remove the rust from your drums enabling you to simply Scotch Brite the surface. A soft wire wheel will work quick and easy if you have one.

 

[67Dart273]

There are basically 3 books to have. 1 was already mentioned, the other is this, not the link to buy but the book title/ author..., Munroe

Torqueflite A-727 Transmission Handbook HP1399 by Carl Munroe: 9781557883995 | PenguinRandomHouse.com: Books

This book provides step-by-step instructions for how to modify Chrysler's 904 Torqueflite automatic transmission for drag racing, road racing, and circle racing. Topics include theory of operation, transbrakes/valve...

www.penguinrandomhouse.com

and then an OEM service manual for the transmission you are using. That part is easy, go to MyMopar and download the appropriate service manual, free:

You may need to get Dodge vs Plymouth, depending on year

Service Manuals – MyMopar

mymopar.com

 

[Austin Spencer]

If you are in no hurry and have it lying around, soak the rusty parts in Evaporust. It'll remove the rust from your drums enabling you to simply Scotch Brite the surface. A soft wire wheel will work quick and easy if you have one.

I'll probably be doing that, I've got the time so I'll look into that today.

Here's some more pictures of the light rust on some of the parts I've got.

That last picture just had some loose rust gunk, wipe off but it looks like this must have sat for a while so the bottom of each drum got something in it. I'll see if I can put every part into the Evaporust and leave it for a day, see how it goes.

I checked out the clutch plates in the direct and forward drums, and they seem like they are pretty unused, the few grooves they have are pretty pronounced. One of them had some wear inside of the groove, but other than that anomaly they were all the same.

One thing I did notice as well was that my direct drum has a lot of space between the pressure plate and the snap ring that holds it all there. From the video I was watching they said about .015" per clutch plate, so with my 5 plates it should be .075". I didn't bust out the feeler gauges but this looked much too large.

 

[j par]

Lately I've been using a little brass wire wheel on a dremmel for little cleanup jobs that I don't want to get to much material off...
It looks like condensation moisture likely got into it...
On my last transmission, where I got one from a guy... blah blah blah and I went to rebuild it. It had some rust issues like that inside from being in an outdoor shed... Just getting through the heat and cold cycles and moisture...
Anyways, definitely, without question. Pull the pump apart on the front of the transmission that you pulled out first...
There is extremely tight tolerances in there, and if those gears get moisture and rust on them and go uncleaned unlubricated and unfreed. It's likely you'll snap the snout off your torque converter at the first turn of the key... if it moves at all... l o l..
I was glad I opened mine.. as soon as I did I said to myself that's not good.... watch the videos, on scribing them and things like that to get them back where they were..

 

[j par]

Definitely. If you just put new clutches, new steels and your lip seals and stuff like that and clean everything out, put everything back exactly the way you had it. You're probably gonna have quite a healthy transmission for a long time. These are known to be the easiest transmissions. And have great longevity with just a simple rebuild... as far as bushings go, i've gotten away with just putting a front and rear ones in that you don't need super special tools for.. They're the outside ones that generally carry a lot of the loads and are more susceptible to contamination, because they're closest to the outside...
I've just never seen any bad scoring or wear on the inside bushings.... in the four or five that i've done...
Oh, yeah. I commend you for doing this as well. It's really amazes me that there are so many people that have this hobby and are scared of things like this. And really, when they've got and gone through, you can find out how pretty simple it is, it's very very very old technology..

 

[Austin Spencer]

Lately I've been using a little brass wire wheel on a dremmel for little cleanup jobs that I don't want to get to much material off...
It looks like condensation moisture likely got into it...
On my last transmission, where I got one from a guy... blah blah blah and I went to rebuild it. It had some rust issues like that inside from being in an outdoor shed... Just getting through the heat and cold cycles and moisture...
Anyways, definitely, without question. Pull the pump apart on the front of the transmission that you pulled out first...
There is extremely tight tolerances in there, and if those gears get moisture and rust on them and go uncleaned unlubricated and unfreed. It's likely you'll snap the snout off your torque converter at the first turn of the key... if it moves at all... l o l..
I was glad I opened mine.. as soon as I did I said to myself that's not good.... watch the videos, on scribing them and things like that to get them back where they were..

Took a look inside, luckily nothing like the outside rust I've got on the drums. There was some of that loose gunk here or there but it all moved pretty freely. and looked clean thankfully.

Definitely. If you just put new clutches, new steels and your lip seals and stuff like that and clean everything out, put everything back exactly the way you had it. You're probably gonna have quite a healthy transmission for a long time. These are known to be the easiest transmissions. And have great longevity with just a simple rebuild... as far as bushings go, i've gotten away with just putting a front and rear ones in that you don't need super special tools for.. They're the outside ones that generally carry a lot of the loads and are more susceptible to contamination, because they're closest to the outside...
I've just never seen any bad scoring or wear on the inside bushings.... in the four or five that i've done...
Oh, yeah. I commend you for doing this as well. It's really amazes me that there are so many people that have this hobby and are scared of things like this. And really, when they've got and gone through, you can find out how pretty simple it is, it's very very very old technology..

I'll be looking at new clutches, just not sure which ones to get. I've read that you can mix and match to get the right clearance, so if I get some thicker ones I can throw those in, perhaps it'll work with 4 thicker ones rather than 5 slimmer, but we'll have to see. All of the steels were clean, they had no discoloration, but they did all have a very loose circular sanding pattern, like a jitterbug barely went over them. I've seen people take scotchbrite to take the shine off of them for better grip, so I'll likely do that. The inner bushings looked solid, couldn't see or feel any grooves, so those should be fine.

It is definitely interesting getting into this, I didn't expect to be tearing into a transmission and swapping them around on this project but seeing that a core was $400, and a rebuilt was $1800, I figured I'd take my chances and learn a thing or two.

So far it's looking like I'm going to be getting the front servo larger spring, a full seal and gasket kit, some new clutch plates and steels, some Evaporust, and possibly a spring on the accumulator. I've not dug into the valve body just yet so we'll see if that brings any other surprises. I've read that there are slightly different plates that separate the valve body top and bottom, and they are stamped with 3 numbers. Is there a reference anywhere to see what these differences are? Or are the differences so minute it's not really worth looking at?

 

[RustyRatRod]

I'll add one more to the list of publications to get. The ATSG Service Group book for the Torqueflite.

 

[Austin Spencer]

I'll add one more to the list of publications to get. The ATSG Service Group book for the Torqueflite.

I'll look into it. Glad to see that there's so much documentation on these.

 

[RustyRatRod]

I'll look into it. Glad to see that there's so much documentation on these.

A bunch. The books by Tom Hand are also excellent. I have all three.

 

[j par]

We are lucky to have a couple.Good transmission parts places here in portland... i've got stuff at the transmission warehouse, which is well-known here and has a great car show in the spring, but actually the transmission exchange about a 1/2 a mile away, this is where I'd go. I found myself going to get most of my stuff.. they put together a custom kit for exactly what you want... You can tell them you just want clutches and steals, or you just want seals. What you need to do is look at the number on the side of your transmission, the serial number and give them that, and they will have the correct parts for sure... take care of voice command a lot of this stuff so if it comes out can jombled, so be it.... if that was rebuilt with a transgo shift kit, I would definitely look at possibly summit is real good for having instructions available, like, look at their trans. Go to shift kit and follow the instructions for adjustments. When you go to adjust your bans and make adjustments And leave that piece of plastic underneath that chervo, no problem, you'll want it there. It's all part of the programming of the total package of the shift kit... obviously, that wasn't a part of the shift kit itself, but like I use, hey ground down piece of half inch socket in the last transmission... i haven't rebuilt one of these without putting a transport 2 shift kit in it...
These people, also at the transmission exchange in Portland find Martin Luther King. Have been there a long time and rebuilt all kinds of transmissions and things, and I got to talk to one of their texts 1 time, and I was all worried about clearances and all that stuff and the guy just said. Chrysler transmissions like to be a little loose. Anyway, and not to worry about it... that's gotta have a bunch of clearance under that ring. Because his clutch packs have to be separated. When they're not engaged, you don't, I understand having too much clearance and them not engaging correctly, but it's unlikely that that would happen.That piston moves more than that clearance... my advice is a big jar of Vaseline, a plastic toothpick for the lip seals and put everything together. Soak the clutches in a little transmission fluid, smear transmission fluid on everything. Use a lot of Vaseline.
And just take everything apart and put it back together exactly the way you took it apart. And don't worry about stuff, and don't let the gurus on this forum. Spend your money on stuff. You don't need just a basic rebuild. That's going to last year. Quite a number of years, no matter what your horsepower is...
There's a member who his past now, who drag raced several abodies. Well, into the 10 seconds, just doing basic rebuilds for the most part on 904 transmissions. So your seven twenty seven's gonna do plenty for you without doing anything more.It's been a common rebuild...

 

[j par]

Oh boy, that voice command was pretty bad...yikes...

 

[volaredon]

Look into the superior( brand) super servos.
Both are available.

 

[Austin Spencer]

Well I've run into another issue here.

The forward Planet gear assembly housing is cracked pretty bad, as well as one gear having some bad wear on it. Looks like I'll be getting a new one.

There's currently 2 on ebay, a 3 pinion for $65, and a 4 pinion for $125. If I go to 4 pinion, it doesn't matter that the rear planet set is still 3 pinion right? I know the 4 is stronger than 3 so I don't mind going for it as long as I only need to get the one. Also, are there any differences in the years for the planet gears? Do I need to get a specific year range?

Also another thing I saw on the Rear Planet, one of the pins that holds the gear in place was loose, easily slid out of its bore. Are these just put in and then the end hammered to shrink the bore a bit on the end?

 

[VOETOM]

Austin, it may not be an issue but you might try to determine why your front clutch retainer is pre-1971 yet I suspect, based on the three tab thrust washer, the input shaft and the matching reaction shaft support are mid 70s and later. Some will interchange. I think it should have the wide bearing surface on the reaction shaft support to enable you to use the 1971 and later wide bushing retainer. Maybe though, someone just installed the narrow bushing for some reason? It had to have been working but it appears to have lots of different parts in it. Therefore, it would be good to figure out what year the output shaft is as the splines will be different on the front planet carrier that slides on it.