Hi all:

My '02 Expy needed a transmission rebuild right after I bought it in '05, with 65k miles on it. The warranty covered having it rebuilt by a local "guru" known for doing good work. He talked me into upgrading it with "diesel parts" and a supposedly mild shift kit. I was busy and the warranty paid, so I didn't get too involved that time around. The shift kit was a little more firm than I'd like, but the transmission has held up well to the weight of the Expy plus towing.

Now, with about 90k miles since that rebuild, the pump is making noise, and the shifting is getting erratic. This time, I'm considering rebuilding it myself, as I have more time than money, and have 8 years more experience working on vehicles. I've done a manual tranny. But this would be my first auto. I don't know what parts to get for the rebuild, given the first one's upgrades. (The guru retired several years ago with health problems. There are no detailed records of what was done.) Also, if adding the shift kit only added 50% to the life of the transmission, I think I'd rather have smoother shifts. I know my family would.

My questions:
1: What are the internal differences, between the gas and diesel versions (planetaries, clutches, etc.)? I already know my case and torque converter are gas versions.
2: Are there just two possibilities for what's in there; either it's all gas or all diesel? Or is the only way to know to do the teardown?
3: Does the same rebuild kit do either one? That would be nice.
4: Does the same ATSG manual cover all versions?
5: How can I reverse the changes made by the shift kit? Or, are there better kits available now than in '05?

I'd like to have eveything I need before taking the Expy down for the rebuild, to minimize the down time, borrowed car, etc. If there's no way to know what I need beforehand, I guess it'll just take longer.

Thanks in advance,
John.

 

Nothing? I guess I came to the wrong place.

 

That varied year to year. I can't remember everything that changed. Many of the changes for the diesel were for strength that would not affect the shifts, just the ability to hold more torque. Some of them WILL change how harsh the shifts are.
The only way to know is to open it and look.
Yes.
Yes.
Find out what shift kit was installed, look up what it changed, and replace those parts. I can't tell you what it changed. Some change valves, some change springs, some drill out orifices, some do part of those, some do all of those.

That's a good plan. The only way I know to do that is going to cost a lot of money to replace all the separator plates and valve bodies to be sure that everything is back to stock.

The other way that he could have made the shifts harsher is by installing more than the stock number of clutch plates. I think (but I'm not sure) that the ATSG manual will tell you how many plates each clutch has for each application. I know the diesel has more plates in several clutches than the 5.4L would have with the V10 somewhere in the middle. If he did install extra plates that usually isn't called a shift kit.

 

After doing a bunch of research, and realizing I have no way to know what was done in enough detail to prepare, I've decided to have it rebuilt by someone, rather than doing it myself. Thanks for the help.

 

Well it sounds like you got another 5+ months out of it!