Rear fluid/oil

[safaridude]

Okay so now the noise in my van is in the rear. What type of rear fluid do you use? One dealer told my mechanic to use synthetic, the other said no synthetic, only axle lubricant sae 80W 90. I have the G80. Does this make a difference in what type to use?

Dave

[crash]

I have been running Royal Purple in the rear diff of my 99 for close to 2 years now without any problems.

Other than saying: 'no synthetic', did he give you any reasoning for not running it??

[Rileysowner]

Also with the G80, you will need a different type of rear lubricant with specific additives for the locker.

[LiftedAWDAstro]

I run synthetic in everything! For only a few more $$ it is great piece of mind knowing you get better lubricity and a much higher temperature breakdown point. The G80 does not require the additive according to GM.