2004 3500 48RE transmission shifting issues

[John Jar]

Drive it out of the driveway one day and it will NOT shift from 1st to 2nd gear, do transmission oil change and filter inspection, install GM governor pressure solenoid, found low voltage out of alternate replaced that,
Now it shifts 1-2 very difficult but continues to shift to 3-4 just fine, this is when cold, Now it heats up and the 1-2 gears shift just perfect the way there are suppose to,But 3-4 Never found, she is stuck in 2 and will go back to 1 etc. THIS IS WHAT IS GOING ON NOW. I have also change Throttle P sensor and the transmission speed sensor. Someone here knows exactly what I am talking about, BY THE WAY WE NEVER GET ANY CODES!!
Mileage is 140K and she is a gem of a truck, never seen winter

 

[cerberusiam]

Did you also replace the transducer on the gov solenoid block? Did you check the VB harness plug for fluid contamination?

When it is warm it will not shift to OD, is that what you are saying? You to a) see if the ECM is edmanding OD and b) what the pressure in the OD circuit is when demanded.

 

[John Jar]

Did you also replace the transducer on the gov solenoid block? Did you check the VB harness plug for fluid contamination?

When it is warm it will not shift to OD, is that what you are saying? You to a) see if the ECM is edmanding OD and b) what the pressure in the OD circuit is when demanded.

yes on the transducer, yes when its warm it will not go 3rd or 4th, but will cold, not sure about the VB harness will check that and the ECM

 

[cerberusiam]

If you are not getting 3rd gear when warm could be that clutch pack is bad. The seal goes bad or tears and it will apply cold but once the fluid warms it will not generate enough pressure to apply the clutch pack. Means the tans has to come out and apart.

 

[John Jar]

If you are not getting 3rd gear when warm could be that clutch pack is bad. The seal goes bad or tears and it will apply cold but once the fluid warms it will not generate enough pressure to apply the clutch pack. Means the tans has to come out and apart.

Thank you