68RFE Question

[tommyturbo]

I recently decided to have my 68rfe transmission serviced as a normal maintenance. It has been driven
with respect for 140,000 miles and is running good. The reason for the service is because the shifts
are not as crisp while towing. 1st through 3rd seem normal but 4th on up are not as quick under a
load. I still practice manually downshifting from 6th to 5th before the kick down by watching the boost
gage. In 6th, the trans will downshift to 5th at around 17 boost psi so if boost gets to around 15psi then I
disengage the cruise and feather the accelerator to keep boost under 16 psi until the hill is passed, then engage cruise when back to 66mph. That reduces the load on the torque convertor clutch.
The fluid was changed at the first 3,000 miles with new filters and Mag-Hytech pan.
I called several trans shops and even a dealer and they all said that it's too late for service and to
just leave it alone. Service is supposed to be every 30,000 mi. They said new fluid would ruin
the wear materials and fall apart. I was actually thinking of a valve body rebuild or upgrade to
help the shifts but was told that the fluid would again have to be changed causing trouble.
I still tow heavy in 6th and there is no slipping going on. Should I take the advice and keep driving
and rebuild when the time comes or should I take a chance of screwing up the trans in the name of
maintenance. It's like the saying "If it ain't broke, don't fix it" approach.
Tommyturbo

 

[xcc_rider]

My BS-o-meter is spiking again.
I cant off the top of my head remember the service interval for the 68rfe but I know it's not 30k miles.
Maybe under sever conditions it is but that means heavy daily towing and such.

If your fluid is still red, clear and doesnt smell burnt then I'd say go ahead and do the fluid and filters.

 

[xcc_rider]

Ok, just looked it up and for normal driving it's every 120k miles. Severe driving is 60k miles so I'll stick to my previous post and say go for it.

The Aisin is every 30k.

 

[tommyturbo]

Thanks, xcc-rider. You are correct as in the maintenance schedule. First change 60,000 mi for severe duty and
first change 120,000mi for normal. What is with these people. I am willing to do fluid and filter service with
the additional valve body rebuild or mod because of what I have been hearing about the wear in the non anodized
bores and ball checks. Possibly even a shift kit. Whatever is better for towing. I believe the OD clutches are still
good so I don't think internal teardown is needed. Even towing with a flat front Cherokee TT down to Rapid City
from the Bighorn Mountains at 70 mph in 6th, the boost was a steady 22 psi into the wind and did not kickdown
to 5th or slip at all. I think the line pressure was higher at 70 mph vs 66 mph.
Several years ago, I approached Mike Lovrich at Inglewood Transmission Service, a well respected GM Allison specialist
if he would service mine. He didn't speak highly of the 68RFE and said he won't do any performance mods as with the
Allison but he did quote me a valve body mod with his very own design fix for the bores and other check ball stuff, a better
torque convertor and a shift kit. He said that is all he would do. I don't hot rod it. Just towing heavy a few times a year.
That was at around 90,000 mi. He said the valve body starts to show problems at around 100,000 mi.
The verbal quote for all that was around $2800.00. Anyway, at 140,000mi, I came back to go ahead and have
this stuff done and he changed his mind about the service and would not touch it. He said that the 68RFE is a problem
child. I must agree just by hearing about the history of the 68RFE. He did refer me to another shop in La Habra and
talking to them, I was told that changing or partially changing the fluid would ruin the wear material and come apart inside.
They said the old oil is keeping the wear material together and to leave it alone. A dealer said the same thing.
Until I find a shop to do the maintenance, I will keep towing fine as always and be easy on the shifting. The fluid
is red and clear and not burnt so my 68rfe still looks like a candidate for maintenance service.
Tommyturbo

 

[xcc_rider]

There's lots of guys changing the trans fluid in your mileage range and a few that haven't by then.
Theres also a thread about installing a built valve body and solenoid pack in transmission's well over 100k. I wish I could find it but I cant.
The general consensus is to do it and reuse it for the trans rebuild when the time comes.

I changed mine around 80k and will again at 40k intervals.

I wish TransEngineer was in town and checking the threads. He would be the final word on the subject.

 

[tommyturbo]

There's lots of guys changing the trans fluid in your mileage range and a few that haven't by then.
Theres also a thread about installing a built valve body and solenoid pack in transmission's well over 100k. I wish I could find it but I cant.
The general consensus is to do it and reuse it for the trans rebuild when the time comes.

I changed mine around 80k and will again at 40k intervals.

I wish TransEngineer was in town and checking the threads. He would be the final word on the subject.

Thanks. I am going to search all info I can from the TDR which has a wealth of info as usual.