How to: 4R70W Rebuild Diary Discussion, Questions, ETC

[panamexplorer]

Tcc & Epc on 1998 4.0Lsohc

I have a question. I am suspecting I have a problem with either my TCC or EPC solenoids. Not wanting to seem like an idiot, but having no experience with transmissions...
Are they accessible from outside the housing or are these parts inside the transmission ?
How easy is it to get to them?

I have lots of suspension, brake, motor and electrical experience and thinking of branching out.

Thanks

 

[CDW6212R]

Those are all inside, the solenoids except the EPC are relatively easy to do. The EPC is in the case and the internal linkage has to be removed to swap it. Do them all if you go in there with those suspicions. They aren't expensive really, and the EPC does begin to wear the trans case after high mileage.

 

[ridemx]

I am currently leaking ATF from my extension housing and was wondering, does the extension housing normally hold ATF, if so if I remove the housing are there any seals that I will need to replace besides the gaskets between the housing and the trans case the the gasket between the housing and the transfer case?

Thank you!!

 

[CDW6212R]

I am currently leaking ATF from my extension housing and was wondering, does the extension housing normally hold ATF, if so if I remove the housing are there any seals that I will need to replace besides the gaskets between the housing and the trans case the the gasket between the housing and the transfer case?

Thank you!!

No, just that rear seal. FYI, buy the Ford seal that has the long rubber boot, not a short seal that may be 1/4" from the trans.

 

[ridemx]

Thanks for the reply but I am still a little confused. Was the "No" to the ATF in the extension housing or to me not having to replace anything else. If it's to the having ATF in the extension housing is there a specific seal that would cause that, or does it have to be diagnosed. And by "rear seal" is that a part in addition to the two gaskets?

 

[CDW6212R]

No there aren't any other seals or parts in there to replace. Very little fluid will get in there, and it's supposed to drain back forward into the pan. The rear seal is the farthest part in the back, on the end of the housing. That's the only thing that seals the fluid in. It seals on the rear driveshaft, and the longer seals keep more debris out away from the seal point.

 

[ridemx]

I guess I should have been more specific, I have the 4x4 so it goes into the transfer case, not the driveshaft. But that makes since, being that it will only leak about one quart of its full capacity then stop leaking until I fill it back up. Thank you very much!!!

 

[CDW6212R]

The 4WD trans will not have a rear seal, the transfer case has a front seal for that. The TC will have the normal kind of rear seal too.

 

[blackmountaineer]

Can you tell me where to buy the seal installer and sizer tool? Thanks.

 

[CDW6212R]

Can you tell me where to buy the seal installer and sizer tool? Thanks.

The front and rear seals are fairly easy to put in with a light tapping of a hammer with or without a socket or piece of wood. Just be gentle and slow at it. Many people have really cheap large socket sets like me, just for that kind of job. I gave under $40 for a 3/4" socket set long long ago. I never really use it except for installing seals etc. Check out a flea market for used tools. I hate Chinese(Asian) products, but those serve a good purpose.

 

[blackmountaineer]

Sorry. i ment the output shaft teflon seal installer and sizer tools. You used a gm solid teflon seal on the output shaft, and I will be building a 4r70w this summer. The idea of using a solid seal on the tailshaft is great, but id like to do as much of the work myself. Thanks again.

 

[CDW6212R]

Okay, find the companion thread to this one. It has all those great details about which internal seals to use, and the tools needed. I bought some of those tools, about $60-$75 each I believe. Concentrate on those internal parts, and that main 4R70W rebuild thread is full of pictures. Chris(Glacier) does a wonderful job of detailing the steps. Regards,

Here's the big thread from the beginning;

4R70W Transmission Rebuild Diary

 

[autotdriver]

are all vb in the 4r70w interchangeable, I swapped trans. and the the one i put in has 2 less pins on the connector than my old one, so i was wondering if I can swap vb and what i need to be careful of if i can change them ?

 

[Cobraguy]

Spend some time going through this site. There is a ton of good information. It's somewhat dated, but then again, so are our transmissions to some degree. Jerry goes into vb swaps.

http://www.tccoa.com/articles/tranny/index.html#

 

[foaktree]

Part # for one piece teflon output shaft seals

I am putting a different output shaft into an '03 4R70W so that it will have a speedo gear. I am trying to find some of the one piece (not scarf cut) seals for the small diameter below the direct drum. Checked with Chevy, GM dealers and they had no idea what seals I needed. Told them that I was looking for that go into a GM325-4L trans some where (per another forum post).

Do you have a part number and a source that can provide these seals?

 

[dancssei]

Reverse/Low servo

Glacier,

Thank you for all the useful information in your transmission diary. I have a 4R70W transmission that works great until it heats up. Once it is hot I have no reverse. This is the first automatic transmission problem that I have had to deal with and I would like to fix it myself.
From what I can gather I think the problem lies within the valve body or the solenoids (I believe it is a pressure issue caused by a bad seal??). Am I on the right track? What would you suggest replacing on this transmission. I plan on selling the truck in the near future and would like to keep the cost to a minimum. FYI it is tough finding parking spots when you have no reverse!

Thanks,
David

Ok I have procrastinated long enough and today I decided enough was enough. I took out the valve body for another inspection and to replace some parts. I have done some more research and looked over the diary again. Before I consider taking the transmission out I want to replace the parts I can access in the pan.

I popped the metal O-ring out for the reverse servo and ATF went everywhere (so did the piston/servo and spring)! Is this normal or have I located the problem, the seal is leaking on the piston/servo. It seems to make some sense considering the seal clearance and force required to push the piston (temperature change and worn seals could make a huge difference). Anyways I was planning to replace the piston/servo and seal today, but my lack of planning and not making sure the transmission shop was open has cost me a couple days. So meanwhile I am looking it over and have come up with a list of possible problems and parts to replace. Here is what I have done.

Checked the shift cable and tried replacing the TR sensor for the shifter, no change.

Replaced the valve body gaskets, no change (torqued bolts to specs). Separator Plate looked ok. Replaced Boost valve, no change.

I think I will change the manual valve on the VB. It moves slides back and forth just by rotating the VB. I have considered replacing the entire VB, but only as a last resort before I disassemble the entire transmission.

If all these fail to fix the problem, it must either be the pump assembly bolts, the reverse band, center support seal, or the mechanical diode. Any of these mean rebuild time for me, lets hope it doesn't come down to that, but crap I'll fix anything thats fixable.
Shopping List:
Reverse Servo/Piston w/ Cover Seal +(Spring and O-ring)-its a 3 grove piston.
Manual valve

Any other ideas? Thoughts? Suggestions?
Thanks,
David

 

[dancssei]

Reverse Fixed!!!

I finally got reverse working! Since my last post I have bathed in ATF 3 times and replaced all sorts of parts with no fix. I replaced the low/reverse servo and cover, the 1-2 accumulator and cover, manual valve. None of these replacement parts fixed the issue.
Today I decided to try a Jmodd (for quick reverse shifting) just for the heck of it and also install a drain plug. I drilled a larger hole in the seperator plate on the valve body for the reverse fluid flow and inspected all the valves. Slapped it back together, torqued the bolts, tossed some new fluid in, took a quick shower, and drove to work. Got to work and I tried reverse, Success, it worked!
I really don't think I fixed the problem, which is likely a seal on the pump, but at least it works and I don't have to park a mile from stores. I think by enlarging the hole I took some of the pressure off the pump seals and directed it to the piston.

Tonight I might just drive all the way home in reverse since I can!
Still more work to do when I get home because the plastic tote I was using to catch the fluid cracked and now there is ATF all over my garage floor.

Thanks for all the great information in the diary Glacier991 !!!!!!!

 

[greythorn3]

anyone have a exploded view of this trans? 2wd version would be best but i will take anything i can get.

wanna see how far into i gotta get to replace forward frictions

 

[CDW6212R]

The 2nd gear frictions(intermediate) are first, at the front. The reverse drum is there which those ride on. Behind that is the forward drum, then the OD drum is at the back. Changing the frictions/steels is very easy, but the seals for the drum pistons takes a special set of tools. If you go into the trans, be sure you don't need to replace the seals, due to age or mileage or a failure. Any debris inside anywhere will likely create new problems.

 

[greythorn3]

The 2nd gear frictions(intermediate) are first, at the front. The reverse drum is there which those ride on. Behind that is the forward drum, then the OD drum is at the back. Changing the frictions/steels is very easy, but the seals for the drum pistons takes a special set of tools. If you go into the trans, be sure you don't need to replace the seals, due to age or mileage or a failure. Any debris inside anywhere will likely create new problems.

well i wonder how much more it costs for the seals. probably not much right? anyidea on the tool cost? if its not to expensive i might try to do it all.