rear dif oil for your rearend

[vector1]

hello richard

we're talking mechanical stuff here.

i put about a quart of some diff fluid in the rear of this car after i got it since it was low and after reading another post about not using synthetic thought i had better check since i had some laying around that i used.

what type of oil is recommended, does it matter synthetic or mineral?

it has the 3.73 rear with al pumpkin and i think dave said it is a jbl rear. guess if i knew what type limited slip was used i could figure it out if there is more than one.

thanks

[Bob In Ct]

The whole problem with transmissions and differentials is that almost all of them have some type of clutch (synchronizer) or another. Thus the need for a fluid that is not too slippery yet provides the necessary lubrication. Whether it is synthetic or not is probably not the issue.

If possible, find out what the manufacturer recommends and go with it.

Bob

[vector1]

thanks bob, i don't know what kind of ls is in there, that is why i'm asking jbl since they put it together.

[427 S/O]

Ford sells 'friction modifier' for the LS rear ends, I put a bottle in my jag., works!.

[Richard Hudgins]

Vector 1,

I am pretty sure that your car has the Ford Traction lock unit. You can use Red Line synthetic shock proof gear oil 75w90 (has friction modifier), or AMSOIL Series 2000 75w90. If you use a standard rear gear lube you will have to put in the Ford friction modifer additive.

I would call Red LIne or Amsoil for their recommendation just to make sure you have the right product for the unit.

[vector1]

thanks richard

[bret a ewing]

I have used Royal Purple Syn with good results. I may have to add a little Friction Mod. - it cogs slightly when making turns. (Shelby/Dana 44 Ltd slip)

[bret a ewing]

BTW - You may not have to add the entire bottle depending on the fluid.