4l60e problems

[heavy_chevy_07]

I have a 02 silverado 5.3 4l60e. I thought I had lost second gear in my tranny. It would go from first to third. So I had a old core out of another truck. So I took the old core to a guy to have my tranny rebuilt. He used that core and rebuilt it. So took it home and pulled the tranny that I thought had lost second. Install the newly rebuilt with a few upgraded corvette servo shift kit and z pack. Got everything all put back together and it's doing the exact same thing going from first to third.

My dad looked online and said he found some stuff about a electrical problem so I was thinking back and this is what I thought of. Dad said he was reading online and it could be a voltage issue maybe.

I was in Kermit about 400 miles from home and I was pulling a trailer with 3 quads and it made a super weird shift from 1st to second. But was fine driving home. I made it back to home and my fuel pump went out so my truck set for like a 4 days till I got my fuel pump in the mail. When I went to crank my truck it was dead. I got a new battery. Now that I think about it. That's about when it started slipping and doing this weird shit. I am gonna check all my fuses

Please help

[skeet]

any codes showing?

[heavy_chevy_07]

any codes showing?

It threw tranny temp circuit high voltage but it went away. We checked the on/off/start wire with a voltage test and it read .1 less than the battery did. I talked to a guy that owned a tranny shop and he could not thing what it could be. I am gonna drop it off at his shop tomorrow