94 F150, 8.8 w/ limited slip. 3.55 gearing

I did a partial rebuild of my rear axle a few months ago. I replaced the outer bearings, replaced spyder gears(old ones broke), and put in a new clutch pack for the limited slip. After driving around for about a month, it felt a little soft so I put thicker shim plates in. Then It was just how I wanted it. It sliped while turning if I didn't touch the gas but locked and stayed locked if I hit over 1/4 throttle. It has been fine untill just recently it started slipping a bit when I turn right. Now it won't lock at all when I turn right but will still lock when I turn left.

I installed them exactly to instructions. I squirted traction modifier on them and let them soak. The gear oil had about 4-5 oz. of traction modifier mixed in.

What am I looking at here? Broken clutch disc maybe? Still needs more shimming? It currently has .045 shims(thickest in the kit). What causes it to only lock one direction and slip the other?

Its the first time I've rebuilt an axle. I had help from my dad who rebuilt a few. All help is appreciated.

 

The Ford Traction-Lok is notorious for being weak. What you had when you first put it together, that's probably completely normal.

After shimming it up, and driving it, you've probably worn out the clutches because they just can't take being shimmed that far.

The break-away torque on an 8.8" Traction-Lok is only 25 ft/lbs. Lift both rear wheels, and put a torque wrench on one of the lug nuts, if you get anywhere near 25 ft/lbs without the tire spinning, that's all you get with the Ford unit.

I hate to put it this way, but you are much better off getting an Auburn HD LS. Breakaway on the one I put in my '96 t-bird was way over 150 ft/lbs, I could take the wheels off and put them back on with both rear tires in the air. And they last forever, you just gotta change the oil more often.

As for locking on left turns and not right turns, that's completely normal. What happens is on right turns, the driveshaft is lifting the right tire, so there's almost no torque being applied to that tire which in turns keeps the LS from locking up. On left turns, you have more weight on the right tire, and the left tire is being pushed down by the driveshaft, so the LS locks up because there is enough torque pushing the spider gears apart and getting the clutches to grab.

art k.

 

Thanks for clearing that up. I was afraid I put in too much shimming. I guess I asked too much of the stock Ford LS. I bought a Ford Racing rebuild kit and it said it was supposed to grab better and last longer than the stock unit. But, I do drive my truck hard. So for a little over $50 and some time, I got 3 months of a good performing rear end.

I'll open it up this next weekend and see if its all ate up. Funny thing is it didn't take a ton of force to put it in. The instructions said it might.

Now I'm considering a spool. Its an extended cab, long bed. I don't think the push in turns would be that bad. I'm not worried about the extra tire wear as I'm sure it won't add up to the wear I cause. Plus I have a bunch of tires availible. Maybe a locker would suit me better.

 

You might be better off with an air-locker - no problems turning in parking lots, and full lockup when you want it.

Whatever I said is not conclusive, but I bet the thing wore enough to not lockup as much as you want it to...

 

Oh and one more thing I thought of. Compared to the stock Traction-Lok, your shimmed clutch packs are probably locking up much more than the stocker ever did. Now, after 3 months, you STILL may have more lockup than the stocker did ... know what I mean?

 

Sounds like he is being hard on rear axle and maybe has big tires too. Money would be better spent on upgrading to a completely different and stronger axle instead of rubber banding the old one together. You should consider a 9 inch or bigger rear axle.

 

Yeah, you have a VERY good point - he might be pushing too much power through too small an LS.

 

Yes he would be money ahead in the long run.

 

No, just a modded 302 and stock size tires. I like to play on the street alot. Brake torques, burn outs, power slides...

The tires I put on the back go bald quick. This truck has horrible axle wrap, too. I'm designing a ladder bar for it. I just like tinkering with it and making it perform better. Its a blast to drive for being such a long truck. I'll be putting wider tires on(about same diameter as stock), changing the gearing to 3.73, put on a high stall torque converter, F250 front sway bar. Before that, I'm putting in a shift kit so my tranny doesn't burn up. So, this rear end needs to be made to handle my driving.
BTW, what rear ends specifically would you suggest?

 

If you want to go bullet-proof with a 302, go with a Dana 60.

But an 8.8 can handle a lot too... but for the money, a bigger unit is easier to deal with... as long as you can handle the brakes, etc.

How many lugs you got?

 

A nine inch is pretty tuff for its size and he has obviouslt exceeded the capacity of his 8,8 since he broke the spider gears once already. When they start breaking, it is time to change driving habits or install a bigger axle.

 

5 lug. 5x5.5 bolt pattern. I plan on putting disc brakes on the back. I'm thinking of just putting a better diff in. I know its a strong axle. I've put it through hell already. Plus, its cheap to re-gear. (Gotta love eBay at times).

 

The 9 inch is even nicer to regear as you can remove pig and set it up on your bench and has a stronger posi unit too. Many years ago I knew street racers that had two pigs that they would swap out. One for the street and one for weekend drags. The 8.8 is not that strong and that fact that you have broken it already tells me that you are flirting with a bigger and more expensive failure. I would not spend any more money on it and would upgrade it before you go further because it will save you time and money down the road. If you want to get really serious, find a D60 to put in but a 9inch is pretty stout and a lot stronger than the 8.8

 

The 9" rear doesn't have VSS, and that can be a problem with a '94 truck.