I have a 1991 Cummings 4 x 4 with 176,000 miles. I purchased it new. It has limited slip differentials front and rear. The limited slip differentials have taken me through some bad snow and mud. Yesterday I got stuck in some snow that I’ve driven through for several weeks. The snow wasn’t any deeper or harder. I was following the same track I did several other times. I got stuck because only one front wheel and one back wheel turned when I applied power.

Is there an adjustment or part to replace to get back my limited slip?

What do I do?

I'm a fair mechanic and have a large shop.

Roger Kaseman

 

I would say to first pull the rear cover and drop the fluid. Look for any broken clutch discs or anything in the bottom. If not resal the cover, put in new fluid and be sure to put in the limited slip additive. The go to a dry parking lot somewheree and drive figure eights for a little while. I have seen the clutches "stick " together and not work. This should help free them up. If not - be ready to shell out 4-6 hundres cuz Dodge doesn't sell any service parts, only the whole center section. Cheaper to buy an aftermarket locker. As for the front, I have never seen a limited slip in the early D-series in the front......not saying it isnt. Just haven't seen it - it would be a bear to drive when trying to turn! Hope this helps!

Andy

 

Once you are stuck the limited slip will no longer function. That has been my experience at least. It is designed to add power to both wheels until you are stuck.

 

The clutches do wear out.

The LSD in my F150 gave it up at about 80k, but still had enough traction to get up the boat ramp, so I mever worried about it.

You can try the figure-8's, and changing the fluid. But, I'll bet you need new clutches. Probably about $300-500 P&L.

HTH

TOny

 

Clutches for the 70's are the same as Dana 60 clutches. They are relatively cheap (about $75) and easy to find. Any of the off-road/4x4 places should have them, or a kit from Mopar Performance can be purchased from a discount speed outfit ( Summat Racing, Jeg's). They can be installed without reshimming your differential as long as you don't swap bearings or haven't spit out any shims.

 

Ebay is also a good source:http://cgi.ebay.com/ebaymotors/ws/eB...MEWA:IT&ih=015

 

I did it in the driveway in less than 3 hours, you should have no trouble. Just pop out the axles, pull the diff cover, remove the bearing caps, wrestle the diff out, take it apart and swap clutches. Reassembly is the reverse of disassembly.

Before you buy parts, it would be a good idea to pull the diff cover and look at the spider and side gear teeth. The clutch pack thickness controls the depth of the gear mesh, so if you've been running for a while with toasted clutches the gears may be trashed. Not a big deal, it doesn't take any longer to change the spider and side gears too.

 

Did you consider putting a detroit in to replace the lsd?
-P

 

Why? Lockers have lousy street manners.

 

They are nice in mud and snow, this is what Roger seems to like driving in. I also read here that many ppl run them on the street without any problems.
-P

 

Did you add a LTD slip to the front diff. They are not LTD slip on the fronts.
And it sounds like the LTD slip clutch pack is gone in the rear diff.
The old style LTD slips work good in snow, and work better than the new style too. But the draw back is, the clutch pack is vulnerable and the chatter on corners.

 

The chatter on corners can be all but eliminated by adding the additive from your local dealer. Not too expensive either- like 10 or 12 bucks as I recall.

 

One of the things you can do when you are stuck with a limited slip that is not engageing the other wheel is to apply the brake lightly. With one wheel spinning, the clutches do not "feel" any resistence and will not engage. Put on the brake, you will fool them and they will engage.