4LE80 Shifting woes

[tennessebiod]

Greetings,
I am posting here because my 91 Sub(though it is a 6.2) has a 4L80-E .
Anyway the problem had been difficult upshifts-it would require revving well past the normal shift points before it would finally make a hard upshift. As this is a relatively new vehicle to me(8 mo's ) and has 227,000 miles on it I assumed it was time for a tranny rebuild. The fluid was bright red and had no bad smells ( though I have never serviced the tranny in my 6k miles of service).
The transmission shop who is working on it report that the 2 diagnostic codes it produced were 1-a bad solenoid(they reported replacing 2 of them with no change) and 2- a bad TPS which they replaced and say that it now shifts normally but will no longer go into overdrive.
They have not torn open the case as they felt that might not be necessary. They have had my truck for 3 1/2 weeks and I am about nuts. They have a good reputation and have rebuilt other trannies for friends and family so i feel they are honest but maybe suffer as many from lack of experience and knowledge of diesels.
Any suggestions would be appreciated
Thanks,
Chris

[Dimsdale]

Does the tranny still give a code with the new TPS and solenoid?

I had a problem with a crushed wiring harness somewhere near the bellhousing. Try moving some of the tranny harnesses and checking all the plugs for looseness and dirt/water (I pack all of mine with dielectric grease). Check grounds too, wherever you can find them.

Hope this helps!

[markrinker]

Not sure how things work in Tennesee, but in Minnesota, if someone had your truck for 3 1/2 weeks and hadn't pulled a high mile transmission and opened it up to troubleshoot/rule out a mechanical problem - they're either:

1) Waiting for you to approve the labor and quit hoping that it is something external and inexpensive, or

2) Incompetant. Ttake your truck somewhere else.

I can have a 4L80E transmission rebuilt or replaced - both options with similar warranties -in about 48 hours here in Elk River, MN.

Plan on spending around $2500.

[tennessebiod]

Thanks Dimsdale and Mark,

The shop called Mon. morning with news it was fixed. They apparently had difficulty adjusting the TPS and eventually were able to once they stopped following the shop manual recommendations. Apparently this model was the first to use the electronic version of the 4L80 but because of its good old mechanical IP it lacks an engine computer which would have simplified the TPS adjustment. The bill $486 for a new TPS and new solenoid A&B , fluid and filter change. It shifts better than before though I can't tell if the overdrive and lockup torque coverter are working as before. It shifts from 1-2 about 15 mph then 2-3 about 25 and then into OD about 35-45 but when cruising above 55mph I tried several times tapping on the brakes to detect a slight increase in engine rpm ( it did this before my shifting troubles) but couldn't seem to notice any change in rpm.I read about this somewhere on the Diesel page but have forgotten where .Anyone out there know?
Thanks
Chris