Drove a 94 Cummins auto that looks all stock. 200K miles. When cold, 30* all the way up to full operating temperature, it will not shift to a higher gear until about 2700 rpm or so. It seems to start defueling at that rpm too so it needs some tweaking.

Does this seem like a TPS or some other adjustment or deeper trouble?

I did not drive it to full operating temp., short on time. This may get swapped into an older truck, if you know what I mean?

I will start searching old posts too.

Thanks.

 

Did you check the fluid level and if so was it dark.
There is a temp sensor on the trans line by trans that can go bad but can be fooled for pennies. tps could be out of range which will give bad shifts. alternator noise interference affecting computer. bad grounds affecting computer.
I would at least do these before spending big money on a trans that might not really fix the problem.

Wayne

 

Thanks Wayne. The fliuid and filter had been changed recently so it looked clean. Was on a hill so I just pulled the stick when cold to smell it and look at it. The truck is not too expensive, leaving some room for repairs if needed. Hate to need to pull the tranny, it seems to shift pretty tight when it does shift.

 

the 47RH is hydraulically shifted ( 47rH ). the only thing electronic is O/D shift and convertor lock-up. tp and trans temp sensor only influence the O/D shift and T/C lock up. do all the gears shift at this rpm? maybe check t/v cable and linkage. maybe stuck valve in v/b. without knowing all conditions it would be hard to guess and it would help to know if warm temp is the same.
safe for anyone to assume trans is weak at 200k unless a rebuild was recent

 

I was wondering about the t/v stuff. I have never had one get better when warm, leading me to think stuck or sticking valve bodies. If it shifts correctly when hot, the adjustments should be okay.

It shifted at high RPMs in each gear change, 1-2 and 2-3 but I think o/d and lockup in o/d was at normal RPMs.

I think the tranny may be original, which would be nearing its lifespan's end....

If I get the truck purchased, a can of Trans-X or similar may be tried.

 

Have you every adjusted the bands when you do the fluid/filter change? That's helped my slow/sloppy shifts before..

 

I talked to the owner today and he says it has acted this way for 2 years. A Mopar Wrench (retired) today told me it may be the governor in the tranny acting up. The fix would be pulling the transfer case and the o/d off the tranny and fixing or replacing the governor.