New to forum and need help

[IKeelULotz]

Hello all! I just officially joined the site. been on a few pages before but i finally got around to making an account and such. My baby is a 07 silverado 1500 classic W/T package single cab short bed. has the baby 4.3 (for now) with the NV3500. rear end has been swapped to a z71 rear end (RPO codes gt4 G80 limited slip, 3.73 gears). i added a center console and made a remote shifter for it to work. have SS wheels (GM not ebay knock off or replicas). rear end is lowered 2 inches (more to come for the front and rear). 

 

Anyway with all that said, ive been having an issue with it since ive swapped the rear end. the factory one started humming, and the truck had drum brakes from the factory (ew). with the 4.3 it hated hills and acceleration. so i knew i wanted at least 3.73 gears, and with plans of an LS swap i knew i wanted a LSD (limited slip diff....). so i found a good z71 rear end and pulled everything to do the swap. while i was there i got escalade rear calipers (dual piston and larger rotors). got everything swapped and fresh fluid in the diff (even the expensive Acdelco limited slip additive) and went for the first drive and the BRAKE and ABS lights come on. so i went back to the house and flushed the system with DOT 4. went for a drive and the same lights come on after about 2 miles or so. I.m OCD about my truck and want everything to be clean and working properly. so my question to you folks who hopefully have knowledge on this subject is, is there something that needs to be reflashed or something im overlooking that i could check? Also, the truck i pulled the diff from was a extended cab, and the parking brake/e-brake cables dont fit. so any help there would be awesome too!

 

I'm hoping this post got in the right place, i know there are some amazing and knowledgeable people on here.  

 

[txab]

You need to look at any stored brake (ABS) codes

[IKeelULotz]

If i remember right the tech 2 said i had low pressure, or insufficient pressure. something like that. havent had it scan while i was driving with the lights on though