hey everyone, me and my dad have an 08 roush mustang together and i am about to do a rear differential fluid swap. I was wondering if it’s just like a normal gt and it’s the the lsd with clutch packs where i have to add friction modifier or if they put a different diff that doesn’t require it. I can’t find a build sheet on it. What’s everyone’s opinions??

 

I can't answer if Roush used the standard traction-lok, or a Torsen type rear end. The only way to know is open 'er up, or contact Roush. I would guess it is a Traction-lok. Either way, the additive is cheap...I would pick some up in case you need it. The best stuff to use is right from the Ford dealer. A 4oz bottle was under $10 last time I got one. Many gear lubes will say "no additive needed" (especially synthetics)...that hasn't been my experience. Some are better than others, but all will growl or grumble on tight turns in my cars without an additive. Again, from experience, the official Ford additive is cheap and works great if you need it. Cheap insurance if you don't.