Sofa King
Sofa King Reader
3/11/11 11:20 a.m.

I just picked up a Ford 8.8 Differential for the Challenge car that I am working on. I bought it from a fellow GRMer (Thanks Ray!) but he didn't know much about the unit. He had planned to rebuild it, so it didn't really matter to him. I, on the other hand would rather not touch it, and use it as is. What I am trying to determine is whether it is a limited slip or not. The ID tag is missing, so the easy way is gone. By turning the pinion and counting the axle turns, I am pretty sure that it is a 3.55. I know that it is out of a 2002 and up Explorer. When you turn the pinion, both of the axles turn in the same direction. I assume that this is a good sign, but since there is no load on them I am not sure that this is a positive identification. I have also found a photo on line that indicates that a "visible bar" inside the unit also indicates that it is a limited slip. My unit has this, but I can't find any other mention of the bar being a definite indication of limited slip. Does any one out there in GRM land know for sure?

bravenrace
bravenrace SuperDork
3/11/11 11:23 a.m.

In reply to Sofa King:

Generally, if the axles spin the same direction it is a limited slip. Have someone hold one side while you turn the other. If you can't turn it easy and when you do it still goes the same direction, then it's a limited slip. Or you could try to turn it in opposite directions and if you can't, it' a limited slip. All of this is assuming the diff is in good shape.

Sofa King
Sofa King Reader
3/11/11 11:26 a.m.

That's what I thought, but I thought that some of the different ways to skin the cat can fool you! ie; Torsen vs. viscous.

aussiesmg
aussiesmg SuperDork
3/11/11 5:34 p.m.

If the Explorer was a V8 it is definitely a LSD. Sounds like it is anyway from your description, btw how much power are you making, because I blew one apart at the challenge in $2010 for all and sundry to witness

Javelin
Javelin GRM+ Memberand SuperDork
3/11/11 6:27 p.m.

All Ford 8.8" diffs with an LSD are "Trac-Loc" units, IE - clutch-type LSD. Look at the gears and if there's clutch packs it's an LSD, otherwise it is not. Just pop off the rear cover and have a look.

Sofa King
Sofa King Reader
3/14/11 8:59 a.m.

In reply to aussiesmg:

Yeah, but you were probably using one of those inferior Australian units, This one is 'merican!

According to the manufacturer, my motor should make between 310 and 345 HP depending on what car it was in! It will be in a sub 2400 pound car, so I am hoping that it will be a little easier on the related components than a heavier vehicle.

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