I have an 02 Tahoe Z71, tranny went out so I had it rebuilt. Got everything installed and now its doing some weird stuff.
Everything works fine for a few minutes then it will throw an ABS light, parking brake light comes on, and the speedo quits working and it wont shift.
Any ideas?
I've tried swapping out the speed sensor but it didn't help.

 

When the speedo quits working the PCM thinks the speed is 0 mph and the trans will not shift regardless of anything else.
We had a similar thread last year where the OP finally determined that his speed sensor connector terminals were badly corroded. Check that carefully as you have already replaced the VSS, which was the correct thing to check/replace first.

 

Would that cause the ABS light to come on though?

 

I believe it would since all the system is "integrated" electronically.

 

Still trying to figure this thing out, any help would be appreciated.
I bought an ABS reader and it indicated the ABS control was bad. Replaced it but its still doing the same thing. The guy that rebuilt it (took mine in and gave me a rebuilt one) said it was from an 04 and mine is an 02 could that be an issue??
Only other thing I can come up with is that he screwed up something internally in the transmission/transfercase/wiring somewhere because it was not doing this before the rebuild. It wouldn't shift gear when I pulled it but it could be manually shifted but never threw lights or went into limp mode.

 

I've checked the connectors for corrosion (had the same issue on my 06 silverado Computer terminals), checked the ABS sensors with a reader, checked fuses and relays and everything looks good that I can find.

 

Nothing internal to the trans will cause any of these problems.
This is an electrical gremlin. I would suspect an intermittent break in the VSS cable if the connectors are good.