I have just accquired 2000 F150 4x4 and the rear end shudders around corners. Pretty sure the clutch packs are shot the diff oil is GREY. I am mechaniclly inclined but never rebuilt a rear end before. How do I find out what I have for a rear end, the parts, and info pertaining to rebuilding the rear end. Also the trans really slams when down shifting from O.D. to passing gear. Any info or expertise is very much appreciated

 

I dont know on the newer trucks but on my 91 it had a tag on one of the bolts for the rear diff. that said what gears it had, hope that might hlep you.

 

found the tag but how do i read It

 

Get the axle code off your drivers door sticker and match it up below
Partial list:
non-limited slip
27 – 3:31
19 – 3:55
26 – 3:73
25 – 4:10
limited slip
H9 – 3:55
B6 – 3:73
B5 – 4:10

If you got the ls rear I would try and change the fluid first and add the friction modifier to it. It may fix your problem and is worth a try.

EDIT: to the site

 

O.k drained and cleaned the diff to the best of my abilities added friction modifyer to the oil all bought at ford. Drove around and it helped some but it's still there. I think I am going to have a new diff installed in the housing any suggestions or personal experiance on what to look for not to get?? I use this truck as a daily driver some towing, and mild to moderate off road use. Nothing radical though I have still to get good tires and rims. Oh yeah I wrote the numbers down off the diff and Ford helped me read it. 9.75 ring gear with 3.55 posi thanx for everyones help.