I just bought a 99 nbs and recently fixed some things but his trucks diff went out before I bought it so my father in law swapped one in from a junkyard and now the ABS and parking brake light stay on and it reads 10 mph when stopped. He mentioned he thought it was a rear end from a HD? can this be possible and if so how can I make sure and how to turn off the lights?

 

Is it still a 10 bolt?

A heavy duty unit from like a 2500 or 3500 is a 14 bolt and would have 8 lug axles stock.

 

It's still a 10 bolt 6 lug so guess it's not a HD rear. Is there anyway to see the ratio or code on the rear somewhere? He said the lights came on and speedo was off right after the swap. Not sure if it had anything to do with the swap or bad install or coincidence.

 

Most likely the rear end ratio does not match.

Look in your Glove box for a list of RPO codes

The G code's will tell you what it is supposed to have.

The only way to know what's in it is to open it up and look. It will be stamped in the Ring gear.

Only way to fix that would be to get a tune. They can adjust gear ratio in the software.

 

I get the speedo and sensor light being on for that then but why the parking brake?

 

I don't think they have it stamped anywhere on the rear end itself.

You can still figure out the ratio in that rear end without taking the cover off, just have to do some spinning of the tires and counting the driveshaft turns. Youtube is your friend there for visuals.

 

Parking brake or ABS?

Parking brake is the mechanical mechanism itself. It has a sensor/ switch on to know when it's applied. that would be a separate issue.

If ABS, That's affected by the gear ratio mismatch.

 

He said ABS light and parking brake light came on right after the swap. I just didn't think the parking brake would have anything to do with the gear ratio. Ok I'll try to check tomrrow what the ratio is.

 

It's been so long since I have seen one in person with a gear ratio mismatch.

I remember a check engine light and the ABS light coming on.

 

Amber abs abd red brake light at same time typically mean hard abs control code set in ebcm.... Could be wrong gears... But speedo off 10 mph or around 10 while stopped? That sounds like wiring issue or bad vss...