jaredyocum

I have a LS swap truck I've driven 2300 mi so far and lately the trans is delaying all shifts. It seems like something is triggering it to use some preset logic because under normal circumstances it does 1-2 and 2-3 and 3-4 shifts at 14-1600 rpms and when the throttle is smashed it kicks down and provides passing gear, but when its in this mode then it moves the shifts up to 23-2600 and no kick down when WOT. I have cycled power on the ecm and it some times will come back to normal for a bit and then go back to this default like logic. The trans and engine are from a 99 2500 2wd truck with 130K .

TheNutDriver

iTrader: (1)

Sounds like the throttle position sensor is faulty. A bad reading from the TPS and you get delayed higher RPM shifts, and all other kinds of weird shifting including no kickdown and sometimes no lock up.

bbond105

The throttle position sensor was my first thought. Have you checked for any engine or trans trouble codes?

jaredyocum

Thanks for the reply ,
It shows no trans codes but I have seen a TPS code and I know that the aftermarket Throttle body I bought has a super cheaply made TPS . Ill change it and see if that helps . Thanks again .

jaredyocum

I changed TPS sensor and it didn't change anything immediately but after about 4 key cycles it did come back to normal shift strategy . After 75 mi it still is working fine .