Unpopular rear differential question

xXZ-71Xx · January 10, 2016

Ok, I have a few questions about the available rear differentials in my 99 Sierra 2500 NON-HD NBS (14 bolt SF)that I hope someone can answer as I have had no luck searching online.

1. Was the G-80 option available on this model?

2. Does anyone know where a new Mlocker/G80/Gov lock would be sold for this rear?

3. If all else fails I read that all the HD FF rear axles use the gov lock,Is this true?

I already know that it is a very very unpopular diff but I like them and they are the only diff that I know of that fits my needs. Thanks

Formulabruce · January 10, 2016

Answer is YES. Its a Eaton locker with a gear on the side ( the kind that do not work in reverse, Gov lock) Think its a 10.5 ring gear. I have installed a few in the past. Finding a stock one is very rare though.

The FF axle ( Bigger 14 bolt) has gov lock. Have to make sure you have the right drive shaft , and no disc brakes, "I believe",in a '99 2500.

The FF rear is easy to find in G80 vs the semi

xXZ-71Xx · January 12, 2016

Thank you for the reply, I may just have to look into doing a FF swap in the near future then.

Edit - What year range would be best for a FF rear axle swap? Calling scrap yard later.

Formulabruce · January 13, 2016

Im not sure when they changed from the gov lock style to the cone style, but you would want the Drum brake set up for yours I believe.

These guys are Very helpful and ship all over the place... http://justchevytrucks.com/

xXZ-71Xx · January 14, 2016

Im not sure when they changed from the gov lock style to the cone style, but you would want the Drum brake set up for yours I believe.

These guys are Very helpful and ship all over the place... http://justchevytrucks.com/

Ok, I will look into that place for sure. Didn't notice the part in your post earlier but my truck does in fact have rear disc.