Engine/Transmission (1994 - 1998) Shifting Strangely

[shendren]

just bought a 96 with a 4. 10 rear end. 160kmi. picked it up in indiana...



had the pin tabbed, timing set to 15. 5, valves adjusted, new tires, brakes, new overflow valve, and all fluids and filters changed.



nice little work truck.



drove it to florida (home) yesterday. 1000mi. 19mpg.



got off the exit ramp last night at midnight after running all day with no problems, and when i accelerated and truned to go down a state rd, it wouldn't shift into 2-3rd? i let off the pedal and eased into the pedal againg and it shifted normally.



got up this am and it did the same thing. get on it hard"ish" and it won't shift up. let off and it does.



what in the wide world of sports is the problem?



btw, jessup (ex-cummins guru) did the work on it and said it (the engine) was in great shape.



thanks. scott.

 

[Shrimpy]

Sounds like a good purchase Scott . Here is what I think could be the problem. If it had been sitting or was driven mostly local by the previous owner, maybe the highway cruise loosened up some crud. It could possibly need another fluid and filter change. Just one thing to check... .



Jim

 

[bmoeller]

Throttle valve or TPS adjustment possibly. Check the return spring for the throttle valve lever on transmission end. Had to replace mine, almost ready to break off the end.



19mpg with 4. 10s? That would be nice. I've never had over 16. 5mpg.

 

[JoshPeters]

I'd hook up a scan tool. Mine is shifting funny because the Gov pressure sensor intermittantly reads incorrectly. I just haven't gotten around to replacing it.



Josh

 

[BigPapa]

I've had the same problem for quite a while now. I've been told it is a leaking front lip seal. It doesn't leak externally but leaks pressure internally. It's alot worse when it's cold. I've found idling in neutral or reverse for a minute or two at start up helps alot. Sometimes when it's really cold, I can hardly get it to shift from 2nd to 3rd at all. It started winter before last. Wasn't too bad that winter and hardly noticable last summer. This past winter was pretty bad and it's still almost as bad now as early last winter. I figure I'll HAVE to do something about it this winter or drive all winter in 2nd!



By the way, my truck truck just turned over 170K. The first 75K spent probably 90% of that pulling a 32' 5th wheel. Last 95K mostly running empty.