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Jordo 06-27-2013 12:42 PM

Open diff dificulties
I have a 91 yj with what I found out were open diffs after getting stuck in some pretty weak trails. As soon as there is a little mud under two tires and I have lost momentum I am screwed.

I have heard people talk about "lunch-box" lockers and wondered I they would work for me. My jeep is a 4.0L with a 5-speed standard. Slight lift and 33s. Would I need to buy a locker for each diff? Or will it only work in front rear etc. ?

Thanks in advance!

4Jeepn 06-27-2013 01:14 PM

A lunch box locker replaces your spider gears and locks both axle shaft together. A full case locker replaces the carrier(which the spider gears go into) Popular lunch box lockers are the aussie locker and lock right locker. If you still have stock axles I would look at just locking the front axle, which should be a dana 30. Your rear axle, dana 35 is too weak to put a locker in and can bust with one. The locker will run about 250 bucks.. If you can do the install yourself that will also save money. If you want to put one in the rear, I would consider swapping in a better rear axle, such as a dana 44 or ford 8.8.(though the 8.8 should have a full case locker such as a detroit locker, do to carrier strength issues)

wasomma 06-27-2013 02:31 PM

just remember once it's locked it's going to drive differently on the pavement especially when you turn. I like the the idea of putting a selectable locker in the front if you arent doing crazy trails and that way you don't have to replace the rear axle, this would be a good time to consider a gearing change if you want a little more power back to your wheels after going up to 33s

OverkillYJ 06-27-2013 02:40 PM

For the front I went with a Spartan, which is basically just the updated version of the Aussie. Works nice, only locks when in 4X4. On the road it clicks and that is it.

For the rear it is different though. The 8.8 is great, but I would not lock an 8.8 on a DD unless you go with the full carrier selectable locker so that you can disengage it. Not only do rear locker drive funny on pavement, but the beat the crap out of your tires. Get a Limited Slip 8.8 (AKA Posi) and be done with it until you decide if you need a full locker in the back or not. For me the LSD works perfectly fine. The axle I got cost me $325 already pulled. If I had hunted around I could have pulled one myself for $200-$225.

When I hit the gas all 4 tires turn and the Jeep usually goes no matter what. I say usually because all four tires turning can give you a false sense of security that lands you into some places you just shouldnt go where it doesnt matter that all four tires and spinning. That is what winches are for. :punk:

Jordo 06-27-2013 03:29 PM

Ok. Sounds good. Is it worth locking only the fronts? It seems kinda cheesy but I don't have the resources to do a swap. Plus it's my daily driver. So having it torn apart isn't really an option right now

Jordo 06-27-2013 03:39 PM

And overkillYJ - just to clarify. You say you do have a ford 8.8 LSD in your jeep? Cause I like the sounds of that haha. I want to have 4 tire turning going on. Sick of being stuck in glorified mud puddles

OverkillYJ 06-27-2013 04:13 PM

Yeah I have the 8.8 Rear and a locked front. If you lock the front by itself it will make a bigger difference then if you do the rear by itself. The reason why it the weight of the engine is over your front, and you also have the ability to turn the wheel back and forth to help you pull out of tough spots.

Also, if it is your DD you do not lock the rear. Posi or LSD is the way to go in the rear if you dont want to spend the cash for a selectable locker.

As far as the resources, the 8.8 swap is not too difficult. If you were to pick one up, I bet a local shop would swap it in at a reasonable price, or you could give a friend that has the tools a case of beer to help you out. It is a 1 day job once everything is prepped with the 8.8 and you plan it all out if you have never done it before.

Jordo 06-27-2013 04:39 PM

So how labour intensive would a spartan locker be? And as far as an 8.8 swap. Does it require a different drive shaft or anything?

OverkillYJ 06-27-2013 04:46 PM

2 Attachment(s)

Originally Posted by Jordo (Post 3905650)
So how labour intensive would a spartan locker be? And as far as an 8.8 swap. Does it require a different drive shaft or anything?

I am not sure if you can put in a 8.8 without a different shaft or not since I did mine at the same time I did SOA.

The locker is about 3-4 hours start to finish if you have never taken apart a differential before. You might be able to get it in without pulling you diff, but that was not the case for me. I had to pull the entire carrier out. T

This should help.

Jordo 06-27-2013 06:14 PM

And if I buy a ford 8.8 will I need to get a posi kit or whatever for it? Or is a 8.8 LSD stock?

OverkillYJ 06-27-2013 06:26 PM

It was an option. Some have it some dont.

wasomma 06-27-2013 06:26 PM

8.8 has disc brakes and LSD only in certain years, refer to this article:

Ford 8.8 Axle in YJ

OverkillYJ 06-27-2013 06:42 PM

Yeah as far as finding what you want you need to look up what years have the options required, gear ratio etc...

Mine is a 97 with disk brakes, LSD, and 4:10 gearing

Jordo 06-28-2013 09:45 AM

Ok. Thanks a lot for your help guys! Think I got a plan for what I wanna do. Probably just gunna do front locker for now then see what sort of difference that makes for me

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