So I ordered a level 5 4l65e from a vendor. I made a common mistake when I went to install the transmission I didn't get the torque converter seated right and i sheered the ears off the pump. New pump was installed everything fine drove off for a little while car shifted nice firm everything was good and then the next day I got up and I didn't have 4th gear no slipping just won't go into 4th. Hook the computer up commanded 4th gear it still wouldn't shift into fourth this is a brand new transmission everything I've read is pointing to the servo. spoken with the vendor he's a great guy no issues so is Frank who I've called 3 or 4 times in middle of the night of performabuilt. I guess I should mention it's Corvette servo and let me also say this vendor is top-notch

 

also computer shows zero codes only prob is 4th gear not engaging ughhh

 

Maybe the band was knocked off the anchor when the pump was out.

 

Check that the hole in case to pan rail at servo has not become blocked this will cause no 4th, The band would have to be on the pin else you would have no second,. Possibly some debris from pump being damaged could have found its way to the 3-4 shift valve something to be considered ,

 

well i might be getting in over my head ive decided to send the trans back and have the builder re go through it he stands behind it and chuck has a good rep and nobody likes fixing a mess someone else has started messing with im sure its somthing simple just sucks pulling trans back out shipping it but u play with these toys and its the life