Hi guys, I just put a torsen LSD into my FC, and I was wondering what type of fluid to fill the rear diff up with. Will any 90W GL-5 fluid be ok, or is there a specific brand/weight that you guys prefer? Thanks.

 

i have no clue on a fc but on my fd i use royal purple 75w90. i imagine its gotta be the same stuff though.

 

Thanks, the reason I asked here is because FCs never came with a torsen LSD, we either got a clutch type, a viscous, or none at all. So I thought Id ask here since all FDs have a torsen.

 

Anyone else have any more input on this??

 

The main brands that most people use are:
Amsoil
Mobil 1
Redline
Royal Purple

This list is alphabetical and not in any order of preference. I believe they all come in 75/90. Some have a seperate MTL used for the 5-speed transmissions. Also they are all synthetics that should be from Group VI base stock. (this is a good thing)

I believe there is one other brand of gear lube that is recomended by racers but I can't seem to remember it.

I'm running Amsoil 75/90 in both my gear boxes. Next time I'm going to try Redline MT-90 in the tranny, and ROyal Purple 75/90 in the diff. Just for grins. I believe that all are great products....

 

Any decent gear lube should do it, synthetic is best. To really go overkill you could squirt in a bottle of friction modifier (like EquaTorque), that helps smooth things out, you can even use it in your MT with no ill effects.

 

Yeah I'm using that exact combo right now in California for a few months now. It's a great deal of difference since I had no idea what the previous owner used or how frequently he changed it. RP is good ****.....

-Dan