L480E No Third or Fourth When Warm

[Seamarc]

My 97 works fine cold but stopped shifting into the higher gears when warm. A local shop decided it needed to be rebuilt and did that work. Now, it works fine cold but stopped shifting into the higher gears when warm :mad: . Tranny shop is befuddled. Any ideas or tricks? :confused:

[Seamarc]

Just to update, the throttle position sensor is showing a fault, I have my fingers crossed that this will do it.

[Alvy1976]

Seamarc, are you sure that you're getting no third and fourth or could it be no 4th and TCC lock up? I've had extensive testing with my 94 with no fourth when cold. Good place for info is www.thedieselplace.com under the
4L80e section, many good techs there for trans issues related to that trans. I'm slowly becoming well versed with it myself. Using a good scan tool vieiwing electrical ins and outs is the ticket with that model. Good luck, Mike