Correct diff oil

[tech10002]

I'm trying to figure out what kind of oil to buy for my 3.73 limited slip so I can top it off in an attempt to shut up this low speed whine I'm hearing. The owner's manual shows 3 different diffs with 3 different oils, but it lists them by brand and type. I have no clue how to find out what I have. Does anybody know?

[bmiller2000]

pretty sure you need the sythetic. Mobil 1 is about $14 a bottle. Dana 60?

[Dirk]

syn oil 75-90w front and 75-140 rear. Add the friction modifier to both.

[tech10002]

Thanks. It says on the bottle that it's for limited slips. Do I still need the friction modifier? I'm just topping it off right now. If it still makes noise, then I will drop the cover and put new fluid.

[ford4442003]

Take it in for checking out the whine should be under warrantee the noise will probley not go away because of being a little low but you do need friction modifier with a limited slip but that is to cure around corner clutch grabbing. Greg

[lightninmike]

Yes ^ he said the correct fluid but you can also check the tag on the rear. This has been on every car i have had. Good luck but i dont think fluid is gona fix that problem

[npccpartsman]

If you're just topping off I don't think you want to add friction modifier. If it's whining then you need to take it in if it's still under warranty they don't get better.

Dirko got the oil exactly right. Syn all the way in the pumpkins, but two different weights.

[tech10002]

I picked up some synthetic for the rear diff. It was almost a pint low. It seems to have shut up the noise. I can still hear something, but I think it's just resonance in the exhaust from the turbo spooling down. There are no drips or obvious signs of oil, but there is a buildup of crud around the nose that looks like it could have had oil around there before. I think I'm going to get a gasket and drop the cover just to be safe.

[Dirk]

Never used/seen a gasket. Just use a bit of black sealer.

[bfloyd4445]

Originally Posted by tech10002

Thanks. It says on the bottle that it's for limited slips. Do I still need the friction modifier? I'm just topping it off right now. If it still makes noise, then I will drop the cover and put new fluid.

If I remember correctly you don't need the modifier with mobil 1. Ask mobil1?