ok so i have a 02 gt 5spd..... it has 70k on it now, and i notice that every once in a while when i take a ride turn hard.... only that wheel spins........ so i guess the friction modifier for the limited split discs is worn out.... what fluid do i need to put in it so they will grab again.... i was thinking the royal purple, but does that have the necessary friction modifier additive that i need?

 

I used to do RP and the friction modifier. Back when I used to use it, now im too lazy and just do the RP, seems like everything back there is fine. got 67K miles

 

thanks.... if i add the extra friction modifier will that help me out on my one wheel peel situation

 

No!

Friction modifier makes the oil more slippery so that the clutch plates do not bind--adding more will make it slip more...

"Back in the day" a cheap trick for the strip was to use less friction modifier (or even none on a trailered racer) to get more lock-up. With none, on the street, the clutch packs will pop and creak and make a general racket.

 

Royal purple has its own additives for the Posi, and so does the Redline I use; But everyone i spoke to told me to add the Ford friction modifier..seems to be doing well

 

You don't need FM with any synthetic gear oil--not really because it already "has it", but because the synthetic oil in inherently "slipperier" then dino oil.

Adding FM to synthetic gear oil will further lessen the clutch packs' ability to lock up.

 

Agreed, and well stated CliffyK .

 

So it appears there is an issue with the clutch packs, not necessarily with the friction modifier.

 

I agree...

Most likely, fluid isnt the issue. These 8.8s take a lot of abuse, and people seem to forget about the clutch packs back there. I know my car needs a rebuild... I bet thats what your rear could use. I've even heard of people adding extra discs in there to make it lock up better, but driveability may be hindered..

 

Unless some misguided soul loaded the rear-end with synthetic oil and FM, and then more FM 'cause they had an ***-end to understanding of which way friction modifier modifies friction...

If so and I knew the LSD had not been abused, or had a ton of miles, then I'd drain whatever is in there out, fill the pumpkin with straight 75W-140 dino juice (no FM), and drive it for a bit.

This is a bit of a kludgy/sleazy "fix", however the friction plates may be so loaded with FM and synthetic oil that they will "dry out" and start to do what they are supposed to do--and if they start to bind (you will know it if they do) you could throw in a couple ounces of FM...