Ford Sterling 10.5 rear diff?

JeffH454 · Dec 18, 2013

My 00 PSD F350 SD daily driver/ trailer dragger that has the factory LS in the rear 10.5 has started sucking more than usual. When new it was only OK and required to spin the hell out of one tire to get the limited slip to start working. I'm considering rebuilding the LS and have heard that there are a couple tricks to improve the performance a bunch. Things like adding extra fictions and floaters ?

I'd like to add a Detroit or ARB but that's not in the Christmas budget..

Thanks, Jeff

STROKERYOTA · Dec 18, 2013

i have a factory LS unit with only 900 miles on it i'll sell ya $200 if you want it. came outta a '09 we did 2.5 tons under 2 weeks after the owner bought it, i have the 4.10 ft & rr also if your interested

JeffH454 · Dec 19, 2013

Thanks but I don't need another one I need to see if there's any way to make one work halfway decent ... The diff in my truck has worked like **** since new..and from what I've heard every other SD owner say this is the norm. Just wanting see if it can be tightened up a bit.

STROKERYOTA · Dec 19, 2013

broncoparts · Dec 19, 2013

There was a TSB on those trucks for a chatter in the rear diff when turning under acceleration. If you go to the Ford dealer and buy an updated clutch kit it will come with directions about tightening up the clutch pack. Also will need two bottles of friction modifier.

3pgnebs · Dec 19, 2013

Leave the friction modifer out and it will grip better at the expense of clutch life. My dad shims the clutch packs in all the Ford LS diffs he builds to make them tighter/slip less. Unfortunately, it is probably the least biased LS out there. Not enough spring pressure between the clutch packs to really clamp the clutches. If you need both rear wheels pulling more than 15% of the time, I would suggest upgrading the center to a tru-trac or something similar.