View Full Version : Do I need lockers???

05-04-2003, 04:12 PM
I am putting my plan together for Sherman and doing the necessary research.

I have found a lot of info concerning diffs & lockers in the archives and past threads. But applying them to my general situation is another matter. Which leads me to asking all you serious offroad types a question or two.

Sherman will be used as my hunting vehicle primarily. But recreational offroading is something I like to do. He will also be used as my back-up daily driver. (I commute 2.5 hours one-way every 2 weeks.)

LA is primarily mud, sand, and deep gullies was in the sand/clay. There is usually no bottom to the muck, I mean mud, and the mud ranges from soupy to gumbo to quicksand. I will be towing trailers & boats on paved and unpaved roads. My 2 primary duck boat ramps are pushing 45 degrees.

My plan now is 33x12.5s (probably Swampers), cut fenders, and 4" lift. Unless I find some pretty cheap D60s (close proximity to FT Polk), I will stay with the factory AMC20r & D44f.

I am not the type to see how inexpensive I can do something, nor will I put alot of $$$ into an upgrade that is bascially overkill.

I need an adequate back-up daily driver and an exceptional hunting vehicle.

So, offroad Gurus.......what should I do??? There are alot of options, it seems, what would be practical/best for me??? (welded, limited slip, air locker, electric locker, torque locker, etc, etc)


05-04-2003, 04:34 PM
full lock in the rear with limitted slip or cable/air locker up front would be ideal. In sloppy stuff, you want the lockers. If you're hunting the last thing you want is to get stuck in the middle of nowhere. On the flip side, you don't want to lock the front in goop if you're trying to steer (generally a bad idea to steer in goop either way, but sometimes you have to) and locked fronts are no fun on the street. So locked rear with a limitted slip or a locker that you can turn into a free diff is ideal up front. just my $0.02

05-04-2003, 05:43 PM
what are you looking to spent that is a big factor in what you are looking for, as the arb(or the ox-locker) is the best in my book but requires quite a substantial initial investment. are you gonna regear? a locked front is definately not a good idea unless your gonna be rock crawling. a tight trac loc or posi type unit will work for the front or as rob said a selectable locker. i have a full time locked rear (welded) and it is not so great on the road, works great off road though. so some things to think about.
just my opinion on things

05-04-2003, 05:43 PM
I don't know how far you venture into the bad stuff but if I was you I'd throw some sort of full locker in the back (detroit, ez-locker, lockright, etc) and leave the front open. Wheel it like that and see how you like it. If it goes everywhere you need to go, great, you're done. If not, reasses the situation and you can go with a limited in the front or something more but I think a limited would probably be what you need. Take it one step at a time so you can learn exactly what you want and not blow excess money that could be spent on beer ;) Forget welding, from what you described on how you use your truck you wouldn't like a welded diff.

05-05-2003, 01:40 AM
I agree with andrew. Just having a locker inback makes a huge diferance to the places you can go. Places that took 4wd before can probably be negotiated in 2wd now with the locker. I use my cherokee as a semi daily driver, annd its decent on the street with the detroit. It did take some getting used to though.

05-05-2003, 01:55 AM
Lockers are a great help off-road. Not so good on-road. I had a Lock-Right in the rear of my '99 TJ. It pushed in corners, had some torque steer too (pulled hard to one side when accelerating quickly), made it lurch a bit during low speed tight turns (like parking), made odd wear patterns on the tires. I removed the locker before I sold the TJ, I had about 10K on the locker. The teeth showed what I thought to be an inappropriate amount of wear.

So, my lesson from all this is, no more lockers for on road. I'm going to limit myself to the more expensive selectable lockers, either an ARB or an OX locker. That way I'll have good on road manners and still be able to lock it up if I need to.

05-05-2003, 02:57 AM
It should be mentioned that all the negative onroad effects of lockers are greatly exaggerated with a short wheelbase. What you experienced is not indicitive of lockers in a long wheelbase FSJ.

River Beast
05-05-2003, 03:24 AM
I ran detroits front and rear... I love them off road except when you have to turn tightly in some hairy stuff... it bites hard and makes steering a bit hard but worth it in my book...

My front D60 is open right now.... I dunno what I'm gonna do with hit yet....OX or E-locker.... not sure... $$$ is always an issue.... :D

05-05-2003, 05:08 AM
I get mega torque steer in my cherokee if I am accelerating hard. When I shift from 2nd to 3rd, or 3rd to 4th while on the gas hard the front end will jump over. Going around in parking lots and such is fine for me, unless I am going up hill which causes the detroit to lock, then it will chirp some. I havent noticed any steering problems or anything otherwise. My turning radius hasent changed any. I have gotten very used to the way my cherokee acts with the locker though. And being up here in the mountains, it has helped me on the street MANY times. And reguardless of what some others say, my locker has helped me in ice situations a LOT. Going up steep hills, before one tire may break loose and cause me to stop moving forward (even with studded tires, very steep hills, like 20% grade) With the locker, one tire slips, I here the locker clunk, and the other tire pulls me up.

05-05-2003, 06:16 AM
OK, lets's see if I got this correct.

For only offroad...welded F/R, locked F/R, or selectable lockers F/R.

For a mix of on & offroad......max performance on & off: selectable F/R; average performance: locking rear & open front.

Is that about right????

I am not too worried about the money end of it. I am limited in time more often than money.

How reliable are the non-selectable lockers??? Are there times that they get "confused", if so, then I can see why they could be a PITA on the front??

And are there three types of selectable lockers??? Meaning...air, electric, and a manual cable-style.......and who makes each of these??

Andrew I intend to do this once. I very much understand the one-step-at-a-time approach. But as I said, time is my big limiting factor. So it behooves me to ask these type of questions to folks like you, so hopefully, I only have to tear into my diffs once. I believe that, with the wealth of experience on this forum, all I have to do is ask the right questions prior and do it right the first time.....

Midnightwagon yep gotta re-gear. But have not gotten that far yet in my research.

Still understanding all this and trying to come up with a well-informed plan.......

05-05-2003, 07:31 AM
Make sure you choose a locker to go with your gear ratio. As the carriers vary just like a regular carrier will.

Cable actuated = OX Locker

Air = ARB Locker

Electric: Detroit and eaton

A non selectable locker is always locked for the most part, with a few exceptions. Like the detroit locker I have, if I am just rolling and not on the gas then its generally unlocked and will allow me to turn easily (mind you have have a stick, it reacts very different between an auto and a stick). But if I get on the gas, then it locks and provides positive traction. A detroit can get confused sorta, once in a great while it will bang (very audible, sounds like a sledge hammer on the axle housing). But for the most part the newer style "soft locker" detroits are quiet. The old ones were very noisy. Around corners and such they would click and bang.

For reliability, I would rate a detroit as being the strongest non selectable locker ever made. Rare to see one break. The cheaper "baby" lockers are much more prone to breaking. The OX is supposed to be very strong, as well as the ARB.

05-05-2003, 07:41 AM
If you're going to tow DO NOT USE AN AUTOMATIC LOCKER. I cannot stress this enough. When coasting, the additional momentum pushing against the truck will cause enough compression braking to prevent the locker from unlocking. This can have all sorts of negative results, not the least of which is complete loss of control with associated jacknifing or worse. This is a bad thing. Don't even think about towing anything with a welded or spooled rear end.

You're left with two alternatives: Limited slip or selectable locker. Either option will work while towing and still function as a traction aiding device.

Auburn gear makes a nice limited slip.

ARB makes air lockers. They're nice but they have a tendency to lose air pressure from busted seals if not maintained. You also need to buy an air compressor to run them. (However, this is offset by the other needs an air compressor can fill.)

Ox makes a cable selectable locker. So far they are decent but they relocated their factory recently and are back-ordered. Also, I'm not sure they make one for the AMC20 yet.

Detroit makes an electric locker. It acts as a limited slip when open and a full locker when engaged so it's the best of both worlds. They don't make one for the AMC20 yet.

Front lockers are helpfull but there are some drawbacks. Most common is turning radius while in 4wd. The torque load of driving around the corner will cause an automatic locker to stay engaged. This kills your turning radius. Shifting out of 4WD is usually enough to let it disengage.

If I were you, I would seriously consider front and rear ARB air lockers. One compressor can feed both so that cost is spread out over the two lockers. Additionally, you'll have on-board air to inflate tires or even run air tools (if you get a big enough tank). You also won't have any problems locking up while towing as well as no issues turning on the trail or the street when you need to cut a tight turn.

05-05-2003, 08:01 AM
good point derf. That brings me up to another thing I have experianced. I had about 1500 pounds of green oak in the back of my cherokee a while back, and turning on the pavement was hell. I am actually surprised I didnt break an axle shaft. As I loaded up on a slik dirt hill that I backed up, and there was a ditch that was about 1.5ft deep that I had to go through. So I went through just fine in 2wd (wouldent have with an open dif), but the little bit of slippage caused the detroit to lock. And of course I had to turn sharp just as the rear tires got onto the pavement. Needless to say my cherokee did NOT wont to turn.

I havent had any bad times towing, but the most I have towed is about 1500 pounds with the detroit installed. Most I have towed ever was closer to 4000 with the open dif.

05-05-2003, 08:08 AM
Thanx derf & Stuka.

Limited Slip & selectable are what I am thinking so far.

Next question.....the Auburn Gear appears to be pretty affordable. How much differnce will an offroader like myself (non rock crawler & occasional mud slinger) see/feel between LS & locking????? Should LS be plenty for me, if I have it front and rear??? Honestly, I like the idea of knowing that they are locked, and locked when I want/need them.

Next question......I like the manual (Ox) the best. Just the way I am, manual seems more reliable, less maintenance, etc. I am not going to need these for several months, so them moving is not a big deal, but I didn't see a price for them on the website. How much does an Ox set-up run per diff????????

River Beast
05-05-2003, 08:19 AM
OX's can do for like $650.... higher for the D60 and 14FF that doesnt include the $85 cable for it....

If money were NOT and option for me... I would do OX front and rear, but I already have a Detroit in my 14FF

05-05-2003, 08:23 AM
Looking at prices they range from 650-799 depending on the axle. I too wish I had an OX front and rear, but the detroit was a major bargan, so I couldent pass it up.

05-05-2003, 08:26 AM
Man....$650....that is alot more than I expected!!! OUCH!!!!!

05-05-2003, 08:27 AM
That would almost make me go Auburn Gear LS just to see if I needed more, and if I did, the Auburns could go into Harley....MAN!!!

05-05-2003, 08:29 AM
A detroit goes for 450-550. Basically you get what you pay for. Stronger = more. Selectable = more. The detroit elec-trac and ARB both cost more then an OX does.

05-05-2003, 08:30 AM
I've been wheeling on just a rear limited slip for almost 3 years now. I get a lot farther than the people with open diffs (even if they have bigger tires and more lift).

I still run into trouble going over the really fun stuff.

With the AMC20, you're limited on your locker choices. Though I see from their web page (http://www.oxtrax.com), they do have an AMC20 ox locker (PN OXA20C308H).

I believe Ox lockers front and rear will run you about the same as an ARB front and rear with compressor. The ox lockers are a little more expensive but they don't need the compressor.

Besides that, the cool diff cover you have to use will stand out.

The only limitation with a front D44 OX is that they only make one for 3.92 and up gear ratios. If you're still using stock gears (i.e. 3.31's or 2.73's) you're outta luck. However, swapping in 4.10's or 4.56's would be a snap since all the labor is already happening. If you put some 33's or 35's on Sherman, 4.10's would work perfectly.

Having a rear Ox and front limited slip would be adequate too. And it would allow you to run gears closer to stock.

05-05-2003, 08:30 AM
OH...and onboard air is in the plan. Just not sure where yet. I had just seen it as on down the line somewhere, but if ARBs are thrown in there....then OBA may move up on the schedule.

05-05-2003, 08:32 AM
Originally posted by timmirvin:
OH...and onboard air is in the plan. Just not sure where yet. I had just seen it as on down the line somewhere, but if ARBs are thrown in there....then OBA may move up on the schedule.Expect about $600 for each ARB locker and another hundred or two for a good OBA setup.

05-05-2003, 09:43 AM
derf, at present OBA plan is using exixting york with one or both bumper as tank(s). Will be running 33s, and 4.10 was what I was thinking as well. Will probably swap in D44r from parts GW so that Harley & Sherman have interchangeable parts.

OOPS, there is a poss. plan-changer. If I went LS first then I couldn't swap into Harley because of the gear difference. Running 3.31s in Harley.

Wonder how the max low ratio would do in Sherman???? What is it, like 3.92 or something?? If I went with that ratio, then the diff parts would be interchangeable.......

05-05-2003, 10:25 AM
nope. gear switch point is 2.73-3.73, and 3.92 and up. One thing you could do, if you go to a D44 in the rear. If you think you need a locker, you could put the LSD up front, and the locker in the rear.

05-05-2003, 11:07 AM
So 3.73 is the biggest, HMMMMMMM, wonder how that would do with 33s??????

And Stuka that is just what I was thinking. If 3.73s & 33s would be ecceptable, then if, sometime in the future, I found that I needed the rear locked, then I could switch out the rear LS with a Ox/ARB & put the LS in Harley.

OK, so it doesn't make sense (for the expense) to go double locker right out of the shoot. So let's say I go double LS. Then have to lock the rear sometime in the future.......Would 3.73 gears and 33" tires be worth a :o:o:o:o:o???

I really like the idead of interchangeability of parts. But it might not be worth it if the gear ratio is too low, not to mention the fact that I could easily sell the LS to somebody on here in about ten seconds!!!!!

05-05-2003, 11:29 AM
3.73's and 33's would be equal to 3.31's and 235/75R15 tires. So you would basically be back to your stock gear ratio.

05-05-2003, 11:52 AM
I've got 2.73s with 31x1.50s on Harley and I have been seriously considering going higher.

So it sounds like I wouldn't be happy with 3.73s and 33s. Since this will be only my back-up travelling mobile, running a little higher rpm than I am used to on the highway is kinda expected.

I have been thinkin along the lines of 2500 rpm at 50-55mph on the road, not towing. So I would probably be within 3000 rpm at 65mph. Does that sound about right??? And does that sound like a pretty solid set-up for what I am wanting??? I guess the next question would be......what ratio would give me that?????

05-05-2003, 01:34 PM
With 3.73's and 33's you would be running 2600 at 65mph.

At 3000rpm's with 33's at 65mph you would need 4.28 gears. Which would give you a lot more power, but it sure wouldent be a HWY mobile. You would get ran over here hehe

05-05-2003, 01:46 PM
Check out my signature for a gear ratio calculator. You can try all sorts of combinations to your heart's content. Even side-by-side comparsions.

For what it's worth, I have 3.73's with 31's right now and the gears really are a little tall for daily driving. I'd rather step up to 33's and may do just that sometime in the future.

05-05-2003, 02:04 PM
Thanx a bunch Stuka & derf, you have helped me thru a couple of Sherman issues. Or at least given me the info to now make an intelligent decision.

Shermie will only be a back-up commutor mobile. So if the gears are a little low, that is OK. But if I go to gears like I really want to, then the carriers will not interchange with Harley, should I have that option/need in the future. And it sounds like 3.73s would be on the bottom side of sufficient, however, if I decided 33s were not big enough, then I would definitely be outta luck.

So I obviously have some thinkin' to do.....but it is lookin' like 4.10s, 33s, and dual LS to start with for Sherman......although 4.28s would be some nice power........