Rear end oil

[69volunteer 84]

What weight gear oil on a 8" rear end? Service manual says 4 pints but gives a ford part number for lubricant.

[RPM 1,190]

I've always used 90w.

[MikeStang 247]

I use 80W90 with some of Fords limited slip additive....its a small little white 6 oz bottle...Its some times called friction modifier i think.

Just put that in there, and fill with oil till it just starts coming out of the hole your filling it in.

Bada Bing Bodda Bang

Mike

[StephenC 10]

I use 80W90 with some of Fords limited slip additive....its a small little white 6 oz bottle...Its some times called friction modifier i think.

Just put that in there, and fill with oil till it just starts coming out of the hole your filling it in.

Bada Bing Bodda Bang

Mike

 

This ^

 

I've always used 80W90 LS

[RPM 1,190]

My 69 owners manual shows Ford Hypoid gear lube, Ford part no. C6AZ-19580-B = 90W gear oil. I didn't see where he mentioned a limited slip.

[MikeStang 247]

I always put the additive in no matter what lol, just a habit I suppose or it could be that all the cars I have owned had posi in them...regardless it won't hurt.....80w90 with additive and u can't go wrong

[RPM 1,190]

Mike, where do you get the additive? Online or local?

[MikeStang 247]

Go to your local ford dealer.....they still keep the stuff believe it or not....same for Chevrolet limited slip.....or u can get some at auto zone most times.....or you can get it on line....any of the rear end shops online keep it too....i soak clutches in a mix of 80w90 and additive before rebuilding...then just pour it back in bottle and squirt in rear end lol....ford dealer is gonna be the easiest.....just tell em u need some limited slip additive for a rear end....if their worth their salt they will know what u need

[RPM 1,190]

Thanks Mike. Didn't even think of the dealer.