I have a new fully built 4l60e black panther tranny. Ever since I put it in I really haven't had a full fourth gear. I have played with the PNP switch and I either have no fourth or just a half. I have it in drive and am doing 100 KPH with 36" tires and I am in th eneighborhood of 2800 rpms. I used to be about 2200 rpms. If I switch from drive down to third theres about a 500 rpm difference. Any clue?

 

maybe your converter isn't locking up?

 

no it works fine cause I hear it change when I am on the gas and the brakes at the same time while crusing. Also I had the tranny shop test it with a snapon scanner before the tranny swap and they said the converter was fine it was the tranny slipping.

 

How do you have 1/2 of 4th? Hmm... I would say take to a dealer to have them test with a TechII. That will tell you what the trans is doing at all times (while driving). Or if you had access to someone with HPT, EFILive, etc, you could use that.

You could call the shop you bought it from, and run the symptoms down to them. What you're describing seems like it would be lockup issues. That doesn't always throw a code (at least mine didn't... ), but i dunno for certain.