GM GT4 rear axles

[Falcon_LS]

All I know is I have a 3.73 rear end on my '05 Envoy, but I'm not sure if it's a locker or conventional rear end. Going to be servicing the differential, and I need to know whether or not I need LSD additive.

Anyone know if the GT4 is locker or conventional? Thanks!

 

[wirelessF]

The GT4 RPO code should have the rear end type RPO code following it, if it's like my 02 Silverado.

G80 = automatic rear locking differential. No need for LSD additive.

What does yours say.

 

[MrHorspwer]

Even if it has a G80 locking differential (an Eaton GovLock), it doesn't require any additive.

The only GMT360 vehicles that required an additive were the Trailblazer SS and Saab 9-7X Aero, both of which had a clutch-type limited slip differential.