diff. rebuild/ bias adj.?

[juggernaught]

Anyone had any experience with rebuilding limited slip diffs? Don't have all of my info with me, but understand that you can increase the bias (read pressure) ratio in a Powr Lok unit by rebuilding it with a readilly available kit that will almost give it "locker" like traction. A Powr Lok is what I already have up front in my d/30. Just thought it might be a cheaper/temporary way to go.

[tufcj]

The problem you have when increasing the bias is that the axles and hubs just aren't up to the stresses you'll add. The power lock in my Dana 30 used to pop an axle nearly every trip out with 35" tires. I got so good I could replace an axle in under 30 minutes on the trail.

Rebuild it with stock pieces, but I wouldn't put in more clutches.

Bob
tufcj

[juggernaught]

I have 33" tires with occasional use off road...... I think a Powr Lok is a reasoable rebuild for a d/30 front axle. Maybe not for H/D rock crawling but for a daily dtiver with off-road apps........need more input. The fact that you were replacing axles show that the Powr Lok was working well....

[tufcj]

It did work well. I could get it to pull even with one wheel in the air just by tapping the brakes a bit. It's still being used to this day in a buddy's CJ. He's running 32s or 33s and has a much softer touch on the skinny pedal.

I built a Dana 44 front to 56" WMS-WMS. It's got 4.27 gears and a full Detroit right now. I'm headed back to Chicago over Memorial day to get it out of my brothers garage. I have 4.88s sitting in a box waiting to go in. They'll work a little better with the 37" tires I run now.

Bob
tufcj

[juggernaught]

Thanks tufcj. How difficult is it to actually rebuild one of these Powr Lok units? Are there any "adjustments" necessary during the rebuild, or is it just a matter of reassembling all of the new clutch pack?
I have seen the exploded view showing the two sets of clutches and the split case design. Seems like it could be relativaly easy to r&r. Any Idea what the bias ratio is stock or after a HD rebuild? Have a way cool 4x4 book at home that explains alot about diff bias, just not at my finger tips now. Looking for some practical application experiences from the members.

[tufcj]

We put new clutches in the one my buddy has. Relatively easy, just a matter of getting them in with the taper facing the right direction. The bolts that hold the case together are left-hand thread, which screws a lot of people up.

My 69 AMX has a power-lock in the rear (AMC 20). As far as I know, it's never been apart, and has over 150K on it. The 69 TSM said it should take in excess of 250 FT/LBS to turn one side while the other is held stationary. I put a torque wrench set to 250 on the nut on one side while the other tire was on the pavement and I couldn't budge it. I swapped gears but didn't touch the unit. Spins both rears evenly EVERY time.

Bob
tufcj

[juggernaught]

Just got off the phone with some very knowledgable people at Partsmike in california. They have the rebuild kit for the dana 30 and we talked about adjusting the bias. He recomended Not stacking shims to increase the bias. There is no H/D kit available, only stock replacements.
I think my d30 is probably "maxed-out" with a posi up front and when I decide to go to a locker I will probably swap it out with a d44. I don't really want to start breaking things if I can avoid doing so. I will how ever rebuild the Powr Lok when convienient to get the optimum performance on the trail.