TRH

Hello, I have a 98-1/2 2500 auto. trans. For the last couple of weeks the truck has been jumping in and out of overdrive at approx. 40 - 45 mph, no rough or hard shift have ever been noticed. I once read in one of the forums that the APPS could cause this, the thread also told how to regulate or reset the APPS. I replaced the APPS about 6 months ago. Can someone tell me if this is what's going on or do I need to look deeper????????

TallTom

If you do a search you will find lots of posts on this topic.

I have been through this and first of all check and clean all of your battery connections. This can be caused by electrical noise. You will see post that have you wrap your wire that runs from the alternator to the battery on the passengers side with aluminum foil. I tried this and didn't have any luck.

To make a long story shorter I ended up having my alternator rebuilt. I had almost the same mileage as yours and the alternator was creating enough electrical noise to create shifting problems on my 98.5.

Good luck with this


TallTom

Strong05

I've been having the same problem with mine at 113k. I cleaned every ground wire I could find on the truck, and even added a new one from the ECU to the negative battery terminal and it would still throw fits of locking and unlocking the torque converter. I finally looked up the APPS reset procedures a couple of weeks ago, its a really easy thing to do and so far has solved my problem. Good luck with the repair!

dozer12216

A touchy brake switch can also cause. On mine, a extra pint of ATF took care of after Output speed sensor, solonoids, cable adjsutment, brake switch, and valve body. Won't hurt to try.