Transmission Slipping

[hherifor]

Hello

Just got my truck (2001 F250 7.3l) back from the shop - $2,700 later (blown HPOL and leaking value cover gaskets).

Shop is tell me the transmission is slipping - tranmission fluid is burnt and 2 service codes present for shift 1-2 and shift 2-3. I noticed what I thought was an issue with the trailer brakes where the truck would just slow down - like the brakes were applied when they were not - so this could have been the transmission. I need to get the trailer off and check again

That was the extend of what I got for an explaination.

Can anyone help? What do I need to do? Change the fluid - anything else?

[hherifor]

Looks like I will need transmission. Got quotes from $2000 to $4000.

Anything I should ask for during the rebuild? Beefer anything?

Thanks!