6.0 shifting problems

GMCRush · February 28, 2004

My buddy has a 2002 2500HD that in the last month won't shift from 3rd to 4th once engine has warmed up. While driving it will stay in 3rd until you come to a complete stop. Dealer has hooked up to computer and found no problems.Has anybody else had this problem?

apache sierra · February 28, 2004

My buddy has a 2002 2500HD that in the last month won't shift from 3rd to 4th once engine has warmed up. While driving it will stay in 3rd until you come to a complete stop. Dealer has hooked up to computer and found no problems.Has anybody else had this problem?

hey; mine wouldn't shift into overdrive or 4th either so i asked the guys at the dealership and they said when its cold the converter stays unlocked until the temp gets up to about 180-190 degrees. It sounds like the converter ain't locking up but if the temps are up there hum unless the fluids have been changed lately i don't know

Shaners · February 29, 2004

Dealer has hooked up to computer and found no problems.Has anybody else had this problem?

I disagree with the dealer!!! The truck should shift into OD when warm. When the outside temps are cold and the engine/tranny are cold then the truck will not shift into OD until those components start to warm up.

I wonder if there is a faulty sensor somewhere...

GMCRush · February 29, 2004

He said the dealer had changed shift sensors but the next morning it still happenend. Once the engine temp hits about 180-190 it won't shift until you stop. They will take it back in but have no clue why this is happening.

apache sierra · February 29, 2004

He said the dealer had changed shift sensors but the next morning it still happenend. Once the engine temp hits about 180-190 it won't shift until you stop. They will take it back in but have no clue why this is happening.

have them check the temp sensors as i wonder if the pcm is not receiving the correct info to lock up the converter. You might have him try running about 55 or 60 in overdrive(4th) and watch the rpms then shift the lever down to 3rd and see if the rpms change he might not be in 3rd but not locking up in fourth. Mine did that iwould normally be around 2600rpm at 70mph but when it didn't lock up it would be around 3000 but dropping down to 3rd would raise it up to 3300