There was an old thread like this, solution was never posted and my truck is not happy... so here's what she is doing, the transmission doesn't want to lock up into over drive unless you give it enough throttle. once it lockups up it functions properly but if your let off the pedal a little bit it comes out of od. When driving in any gear (not in od) if you let off the pedal a little or even hold it steady (no longer accelerating) it will actually down shift no matter what speed you're going, regardless of wheel speed (even going down a hill). kind of acting like an engine brake for a couple moments then it will eventually shift up again.

Also while up shifting during acceleration it almost never shifts below 2k anymore... and i can easily push it to 2.5-2.6k then it will finally shift.
Trans was rebuilt 2 yrs ago by a local shop and has a 2 disc TC. has been fine until now, i have 1 more year on my warranty, I will be going to a shop and running codes today maybe one will pop up... engine light is NOT on.


There is a #0 fuel plate in there from previous owner, deep tranny pan
AFE filter and intake manifold, 4"exhaust, a new "above stock turbo w/ 4" output",
It has had electrical issues in the past and i guess a replaced pcm/ecm? (before i bought it)... last night my high beams would start to flick on and off, but low beams were fine
a/c and heat work from all vents (was told to check this to possibly check vaccum?)
She just doesn't seem herself otherwise right now either, idling a little rougher, (could be me being paranoid too though...)
could this be a ground issue and if so where to look?

I can fix things on my truck, with direction, but by no means am I mechanical diagnostician... just don't want to take it in if i can find/fix it myself...

this issue is really getting to me....

 

Took it in got some codes ran:


P1682
Charging output low


P1594
Batt Voltage High


P0622
Generator field circuit


P0123
TPS sensor volts high


Got the charging system checked (obviously) and my batteries are brand new rated at 1010CCA they measured 1432 CCA and 12.81V @ 75*F


Cranking had 11.71V 0A time was 1.12s


Charging system was 14.74V w/ no load, 14.82V W/ load


everything came back normal.... sooo where to go from here??

 

Charging system sounds like its working good. The voltage drop while cranking seems high like a pretty large drop in voltage. I would check the grounds at the main points like battery ground cables and front clip chassis ground. Could be a starter that is worn or in poor shape.
As far as the trans acting up that may be connected to the TPS voltage high code, I would check that. Or re-calibrate it by doing the following here's a link:

https://www.dieselbombers.com/94-98-...djustment.html

Also check the TV cable adjustment:
http://www.dieselbookmarks.com/bombe...Adjustment.pdf

It may also be electrical (Trans OD switch/solenoid problems) but check the above stuff first.

 

we sell a tps delete. the old ones get wore out and its hard to keep them adjusted. they are on our site.

 

Thanks I will check all the grounds and TPS hopefully this weekend.


A friend of mine has a 24v and has all the factory service manuals with all the grounds and what they control... so that's will be step number 1... he has 465K on his '01... I still have 265K to go to catch him .




TPS delete, that's a new one for me... i'll definitely look into that, especially if it IS the TPS sensor that is failing.


Thank you, I'll keep updating progress .