My 99 has this issue going into limp mode when its cold out.. maybe below 50 degrees. I changed out the Governor pressure solonoid, and the transducer too.. Any suggestions? maybe a different brand fluid ? The heat exhanger has been bypassed if that makes a difference, but its not really cold out enough to say so if you ask me ? ? It is fine once the tranny warms up, but this is a plow truck and i need it reliable from the time i start it up and head out..

 

have you tried putting it in N to let fluid flow for a few seconds? if that's it you have a seal leak also how is the fluid level in N warm.?

 

The fluid level is fine, but ive not put the truck in N to circulate the oil..

 

is the tranny going into limp mode or is the truck just not responding to the throttle, also what codes does it have?

 

It only does it when the temps are like below 50 degrees.. once it warms up it is fine and has no issues at all !

 

so what codes do you have, and is it a tranny shifting issue (starting in 2nd gear) or a dead pedal issue????

 

no codes..... it just starts out in 3rd gear...

 

there are voltage regulators to correct this, if your gov pressure is too high, typically this happens if you have an aftermarket VB, or faulty gov sensor. I see you have replaced yours, so I'm at a loss unless your "new " one is defective or the wiring harness inside the tranny is wore thru or has a break somewhere.
Most tranny shops offer free scans and can diagnoise better than we can, they likely can confirm if the sensor is actually working or not.

frequent 3rd/2nd gear starts will tear up the tranny (this I'm sure you already know this)