hi! i just bought a 97 f150 4wd 4.6 auto. i have no clue what type of differential is in it. if im going around a corner and one wheels is on dry road and the other is on gravel, the one on gravel will spin. but if i punch it going around a corner, it;ll drift around the corner and leave 2 marks down the road. if im going through a muddy field in 2hi, one will spin, but if i let it stop then punch it, both will spin. also if i brake stand, both will spin and kick the rear of the truck sideways. so its like a semi-open semi-LS diff.....what is it?

 

could it just be a broken LSD?

 

it could be a miss adjusted ls. (im not for sure though). but look at the backside of the diff at the cover. one of the bolts will have a tag. look for a number that looks like 3L55 or 3 55 i believe 3l73 and 3 73 are also options. the L means you have a limited slip. the space means an open diff. remember it is possible to break both wheels loose on an open diff in the right situation. my guess is that you have a Ls and it is just out of adjustment.

 

3L55! sweet!

now, how do i adjust it? could it just be worn clutchpacks? it does have almost 260k...

 

ive never had to change the clutch packs or adjust one. hopefully someone else will chime in here (they usually do) but it sounds like you are on the right track. you may just need to chang the diff fluid and ad the friction adative to the new stuff. it may be as simple as that.