differential with disposition

[electrician]

It seems as though in the world of diesel with each purchase you certainly enhance any emerging problems. Recently after a wicked wheel, ts chip, 5' exhaust, an edge monitor with juice and a AFE stage II. I found that the Ford "positrac", Limited slip rear end is making a cool and difinative chatter when accelerating and turning, I added some Limited slip Lube additive to it and it maybe lessened yet, didn't go away. Aside of pulling off the diff. cover I have no solutions...
Can anyone offer any advice?

[mschn99]

Originally Posted by electrician

It seems as though in the world of diesel with each purchase you certainly enhance any emerging problems. Recently after a wicked wheel, ts chip, 5' exhaust, an edge monitor with juice and a AFE stage II. I found that the Ford "positrac", Limited slip rear end is making a cool and difinative chatter when accelerating and turning, I added some Limited slip Lube additive to it and it maybe lessened yet, didn't go away. Aside of pulling off the diff. cover I have no solutions...
Can anyone offer any advice?

that is clutch pack chatter, and has nothing to do with any of your mods. it is a quite common thing in a posi, in fact ford is having a terrible problem with the 8.8 and 9.75's in the explorer, expedition, f-150. you could try to add a bottle of friction modifier, go to ford and get the XL-3 friction modifer. go to a parking lot and do a bunch of figure eights with your truck to work it into the clutch packs. if this does not work, they may have already chattered too long and have created hot spots on the disks, and they may need replaced. if i remember right, there was a tsb for some years of superduties for chatter on them.....and if your truck is still under warranty, this will be covered.....Marc