heredia_mike

a friend of mine request your help. his truck seems to be drop/slip into lower gears while at speed. he described it as "no torque loss just a slip into a lower gear then back". happens when he is just cruzing around running down the road. i did a search and found a few things, there is a possible ground issue with the PCM and a U joint vibration that causes the trans sensor to drop trans into lower gears. any other inputs are greatly appreciated.
thanks

Mike

Silverfox99

is he sure its shifting down a gear?? or is it a slight increase in rpms that bounces back and forth here and there?

heredia_mike

he discribed it as both actually. maybe 100 rpm and its done it at different speeds (35/60/45). thanks

Wolfeman

Sounds like the torque converter locking and unlocking.Caused by electrical noise. Clean the battery terminals and ground connections under the passenger battery. do a search, many posts on this.
P.S, Bad batteries can also cause this.

heredia_mike

thanks wolfeman. ill passed the info on. hope its a simple fix.

pdieselpu

Could be the fuel filter as diesels are sooo dependant on fuel supply
Also air filter and tranny has to be solid

pdieselpu

Could be the fuel filter as diesels are sooo dependant on fuel supply
Also air filter and tranny has to be solid