The 31-35" is tire size, than he is talking about gear size. Since you are running stock the gears in the rear you have now are fine. Some of us guys pushing big tires we have no low end. In order to get that low end back we need to gear/change out our ring and pinion. This is one of the things you should have a shop do unless you do it all the time. I don't think you want a total blow up rear end?

 

If'n it were me and I was going to the expense of a new ring and pinion, I'd go the extra and have a good aftermarket LSD in there at the same time.
My trusty old '98 1500 5.9 4x4 came with an open diff (WTF?) and I had an Auburn Gear LSD put in. GREAT UNIT. I know they say the Detroit TruTrac won't wear out over time, but I had 68,000 miles on my Auburn when I traded the truck in, and it worked same as on day one.
Was gonna try the TruTrac on my 3rd Gen when I lifted it, put on 35s and went to 4.56 gears, but Detroit was in the middle of being bought by Richmond, and the TruTrac was back-ordered nationally for about 6-8 weeks on the Chrysler 9.25" model. So, not wanting to wait to do the gears, I went back to the Auburn unit. I kinda would have liked to see the difference 'tween the two, but I don't regret having the Auburn for one minute.
You can't go wrong with either one.

As far as a locker goes, I'm not really a fan of a non-selectable one in a daily driver truck, and the ARBs are just so much money, especially when you have to do the compressor, etc...

 

Then you have about a 30.5" tire. The 2xx by xx by 16 is a metric hybrid of sorts. the last number is always your rim diameter in inches, the rest is metric.

The truetrac replaces your entire carrier, which is the big bell shaped piece with the smaller spider gears in it.

The power trac is a decent unit, but I've heard multiple stories about them grenading so I decided to spend more and be safe. To be fair, most of the stories I've read about them failing are from guys that are using them for more than they were intended. If you aren't going to go 4 wheeling or running massive tires, you should be OK. Kind of depends on how heavy the stuff you're towing is too, should the rear end ever slip and put a load on the power trac.

Auburn makes an LSD that is kind of in the middle, price point wise and it's a really solid unit too.

Don't forget that the Auburn (and I believe the power trac, not sure) require a friction modifier in the gear oil for the clutch pack. That might be the reason your buddy's Cherokee stopped chattering, because the Royal Purple has a modifier already included.

Hammer, you type faster than me, LOL!!!!

 

Thanks for the input. I saw the Auburn LSD on Summits website ( I think ). I will add that to the list of possibilities. The Detroit Truelock looks impressive and sturdy with all of that gearing.

 

FYI...A powertrax is a LOCKER. It mechanicly locks both axles under acceleration, but differentiates when cornering.

The difference between the Powertrax and the True trac (or any limited slip) is what constitutes "limit".
A limited slip differential actually has two limits. The first limit is how much one tire spins before the clutches* (or helical gears in the true trac) engage and lock in the opposite axle. This is usually measured in ft/lbs.
But the second limit is as important. That is the "over torque" limit, where in the clutches will slip and leave you with one wheel spinning, just like an open rear end. As the clutches in most LSD's like the factory one wear out, both "limits" are increased and decreased respectively.
The True trac uses a helical gear mechanism that is claimed to never need rebuilding, which is good. But because it is a limited slip design, it still has an over torque limit, maybe higher than many, but again NOT like a locker.
The disadvantage, if any of a locker, is that as long as an engineered amount of torque is applied the locker remains mechanicaly bonded. Only releasing torque, by say letting off the gas, allows it to differentiate, Since is is a metal to metal lock, it can be noisy or possibly "violent" when it releases. Most of todays lockers are nowhere near as bad as thier early realitives.
The Powertrax design has been around since the early 50's. Trivia...The company's founder designed and built the orginal powertrax to go in his early DODGE powerwagon. Sweeeet!

I hope that helped...

* I left out the early 70's metal cone design, but it works the same way as a clutch pak, and same wear issues. The Auburn is also a metal cone design.

 

I had the tru track for over 2 years i love it compare to the open i blew to peaces. I run the crap out my truck tow a 8000 pd trailer weekly and never have a promblem with it. It can be a hand full in the rain sometimes with street tires on. Also a lot of fun

 

im trying to decide on a LSD myself theres alot to be learned still...i'm also looking into stepping up to either 3.73s, or 4.10s as i can get 4.1os for the rear around 140 buck i think it was. and i got a few buddies that can help me out with the install.

 

Can't get 3.73 gears for a corporate 9.25 axle. you can get 3.21, 3.55(stock), 3.92, 4.10, 4.56, or 4.88.

 

Sorry to threadjack, but aim4squirrels, where did you find 4.88s for the 9.25"? I looked on summitracing and they don't have any! If I can find some thats what I'm going to run after the SAS with 35s.

 

hmm... well in that case its now 3.92s or 4.10s i dont need 4.56s as the biggest i plan on running currently is a 285/75...though once this thing is paid off im gonna get a 5 inch lift and run 37x13.50x16.5 militarys. and then is when ill go to the 4.56s. but for now a 3.93s or 4.10s with an LSD will do... i just need to determine what LSD i want to get.