The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Torsen Diff without using friction modifier questions

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

My local Ford dealer recently replaced the pinion seal and both rear axle seals under warranty. At that time, they neglected to add the friction modifier to the diff fluid. My questions are these:
1) What should the diff operation typically feel like without the friction modifier?
2) How long can the car be driven on the street without the modifier before damage is done to the differential?
 
Yup, friction modifier is only required for clutch type LSDs. If you have the torsen/recaro package, you don't need it

Although, some people add it in, saying it reduces gear noise. I've never felt a difference. Then again, my gears have always whined.
 
The Boss 302 Supplement to the owner's manual that came with my car lists the friction modifier as one of the part numbers for the fluid in the diff. What's up with that?
 
I noticed the same thing in the GT350 Owner's Supplement, that it calls for the friction modifier. The Torsen differential is standard equipment on the GT350. That said I know it was said many times the Torsen doesn't require the friction modifier, even on their website. I believe it's added for noise reduction to alleviate customer concerns.
 

TMO Supporting Vendors

Top