48RE 3rd Gear Shift

[Tobin]

Working on a friends truck with a 48RE that likes to shift into 3rd at about 18 mph. It has a good transmission in it and a tune. I pulled the tune out and it does the same thing, then lowered the governor pressure curve and that delayed the 2-3 upshift but seems like it flares a little. I also swapped out the pressure transducer and put in the GM solenoid conversion. I hate pulling governor pressure out, I am wondering if I should send the valve body off to have it re-calibrated.

Thoughts?

It's a 07 mega 4x4 dually with 3.37s and 35s that he tows with. It needs to hold 2nd to around 25mph or so.

 

[Red Sleeper]

My 05 does this.

John at CRT told me it’s with the TV motor. To play with the timing of that motor or shaft like timing a distributor. Advance and retard the motor to see which way makes a difference. He apparently did this on a 06 truck and the customer was thrilled with the outcome.

 

[Tobin]

Yeah, that affects line pressure. I played with it in the tune and it made a big difference but I wasn't sure if it would be good to drop pressure vs changing a spring in the valve body.

I just got a new tune and will see how it does. I bet it's way better tuning the TVVA.