Will 85-140 diff fluid work in a 2.42 7.5 open rear?

[joesregalproject]

This is what they told me to use at the auto parts store, but I'm still skeptical. I took a sander and wire wheel to my extremely crusty, rusty 2.42 poopy open rear, and cleaned it up a little better. It still looks crappy, but better than it did, and I then primed and painted it with duplicolor high heat in semi gloss black. Now I'm gonna change the grease and gasket. So I bought a gasket and a bottle of 85-140, but I want to make sure it will work ok before I dump it in my rear axle.

 

[79loserbluebu]

That seems a little thick for a rear end I use 75-90W and haven't seen anything that takes a different viscosity

 

[Evan11]

It won't hurt it, but that weight of fluid is more for a worn out rear end that whines or in a rear end of a drag car, etc. 80w90 or 75w90 is the norm. It's not gonna hurt it though.

 

[pontiacgp]

I would use 80w90 synthetic, frees up some hp and it's give you better gas milage.

 

[joesregalproject]

Well as long as its not gonna hurt anything. My car is getting close to 100k, so a little thicker oil probably wouldn't hurt. While I'm at it, does anyone know the torque spec for the diff cover and the fill bolt?

 

[Blew86442]

About 20lbs in a cross pattern and you should be good to go.