So i’ve been having this issue for a couple weeks now, My truck will throw out codes for p1755 and lately p1503. And when the truck is throwing these codes out my transmission will shift very late in 1-2 and then perfectly fine the red of the gears it’s an 07 5.9 with an auto and it’s 4x4 DRW. However there’s times i’ll start my truck and the codes will vanish and my truck will shift completely fine i’ve already disconnected both grounds for an amount of time and it will clear those codes but after a while it comes on again like the next day or so. All help is appreciated thank you.

 

It sounds like you’re dealing with some transmission control issues. The codes you mentioned, P1755 and P1503, relate to transmission problems and electrical issues.

Here are a few things to try:

Check the wiring: Inspect the wiring harness for any damaged, loose, or corroded connections. Pay close attention to the transmission control module (TCM) and any sensors connected to the transmission.

Battery and charging system: The P1503 code is related to low voltage. Check your battery and alternator to make sure they’re working properly. Low voltage can cause shifting problems.

Transmission solenoid: The P1755 code might point to a problem with the governor pressure solenoid. This could explain the delayed shifting between 1st and 2nd gears. If you haven’t replaced it, it might be worth checking or replacing.

Transmission fluid: Make sure your transmission fluid level is good and that the fluid is in good condition (not burnt or dirty).

If the problem keeps coming back, you might need a mechanic to run diagnostics to pinpoint the exact cause.