Lock the front axle or the rear?

[djmac]

I have a d44 in the front and an AMC 20 in the rear both limited slip (but I believe the clutches are shot) on my J10. I can only afford to lock one axle. I have to drive the truck on the street to get to the dunes or trails and I occasionally drive it to work. So which axle would be the best of two to lockup and what would you guys suggest for a locker given the occasional street use?

[shepherdskeep]

Lock the rear first. If it were me, I'd use a lunchbox locker (Aussie, LockRight, EZ locker, etc) - but that will require using an open carrier, not limited slip. The small lockers like this aren't hard to install, inexpensive, and are stronger than you'd expect. It will wear your tire tread faster than the LS, but not as bad as my "lincoln-locker".

[shimniok]

Rear only because it will be easier to steer off-road and you can run 4wd in case it rains/snows without sacrificing steering. I ran with just rear for years in two FSJs and was well pleased. The front ARB doesn't do a whole lot in most cases to be honest. At least that's my assessment so far. I'm sure I will find situations where it makes a night and day difference.

[jeeping1974]

rear first. always rear first. it'll be better on and off road.

[ajbirken]

I am not sure how the rear is going to better on road unless we are talking about Qtrac or np219 or driving in 4wd on snow/ice/rain in which case open diffs seem to work best front and rear.

On the road if you have locking hubs then the only time you will notice the front locker is when you are on the trail climbing over stuff that you couldn't make before (and when you power steering pump is squealing cause it's harder to turn).

If it's mostly trail then I say rear. If it's mostly street then I say front. Just my opinion. There is no right answer. Just lock'em both and get it over with.

[shepherdskeep]

The philosophy behind "rear first" is two fold - first obviously is the steering issue. It WILL be harder to steer in 4WD, period. Turning radius is significantly reduced. If you find yourself off road in a bind on large slickrock, you'll really wish you had hydro-assist steering.

Second, in most wheeling situations traction is needed the worst when facing uphill. The upward angle shifts more weight to the rear of a rig, resulting in reduced weight on the front axle. The axle that carries the most weight load has the greatest opportunity to provide momentum IF traction is acheived. Locking the rear helps provide that traction, and in very uphill conditions the front axle has very little rig weight to draw traction from. Normally in downhill situations the traction is not needed because gravity helps carry the rig's weight forward.

[Hammer]

Also that you break front axles a LOT easier with a locker compared to a limited slip.

Honestly, for most wheelin, I prefer a GOOD limited slip in the front, and locker or spool in the rear.

The really great thing about a locker/spool in the front is the great amount of traction you get going up hills on loose soil. And NOT have to give it as much throttle. Limited slips mean you have to be slipping one to get power to the other tire.

[huebie1]

Gotta say, I love my Detroit in the rear and ARB in the front. Detroits are about as tough as you get and worry-free for the most part. It doesn't have too bad of manners on the road. I am running IROKS on my CJ and don't chirp tires at all (that may change with the 401 this winter!). My Waggy is getting a Detroit in the rear soon.

Don't do a locker in the front first. That's too much force going to the front when the rear is slipping on an uphill section. You're bound to break something, often, with those odds.

[panama red]

My daily driven yj on 38's and daily driven xj on 36's both had welded rear with lockright front. True it will wear the rear tires little faster (not near as fast as a bad alignment), but you will have locked the front and rear and only spent a little money on one locker. You you don't go do u-turns all day/everyday then your rear tires will last a long time.

I see you live in an area with ice & snow. Some of these folks are correct in their opinions, but do not face the same conditions you do. A spool/lincoln-locked rear end can suck on icy roads or even hard-packed snow covered roads. Been there, done that. It is not impossible or anything, it is just a pain and mud-tires and extra HP just make it worse.

If it has to be your DD, you might consider the front if you do a lot of icy road driving. If you can park it when the sleet hits, I'd do rear first.

[Stuka]

I drive in the snow 4-5 months out of the year. I have never had an issue with a locked rear axle. However, if you lock the front, you can forget about turning in the snow, or driving a straight line. The truck will crab walk wherver it goes.

The one time you want to lock the front first is if you have IFS, because you are always lifting a tire up.

[Hammer]

I used to drive my CJ5 with 35" tires in the snow, ice, whatever.
Locked rear, open front.
As long as you know it's going to do it, you won't have a problem with it.
That being said, for actual driving in the snow/ice. Limited slips in front and rear are the best I have had.
For getting stuck in the snow/ice, Spools are the best, hands down. IMO.

Originally Posted by Stuka

I drive in the snow 4-5 months out of the year. I have never had an issue with a locked rear axle. However, if you lock the front, you can forget about turning in the snow, or driving a straight line. The truck will crab walk wherver it goes.

The one time you want to lock the front first is if you have IFS, because you are always lifting a tire up.

Deeper snow is no problem, and off-road is no problem. But a glaze of ice or ice-like packed snow over pavement is a bit different. And when you limit the contact points in these conditions by using an aggressive un-siped tread pattern ( a/t's need not apply), a spool/welded rear can get fun. In conditions that would close the roads or cause most people to stay home a spool/welded rear would be an aid. Using a spool in traffic on ice is not impossible, just a pain. It could be that the weather from the most heavily populated areas of California to the upper midwest is different enough to make everyone right here. My 3 yr old niece who lives near Bakersfield Ca came to visit this summer and freaked over a good ol' thunderstorm with lots of lightning and thunder as, according to my sis-in-law, those are pretty rare where they live. And you would really have to talk to our members who live in the Appalachians about a serious tree-breakin' ice storm problem. Those poor guys get socked regularly in the winter. Snow is baby stuff compared to that. Spools front and rear mean you spin all four tires while sitting still in those.

I guess i did read this and assume serious locking via a spool or welding. A selectable is obviously no problem, where a lunchbox or to some degree a detroit would probably only be a concern with a shorter wheel base and a stick. There again, a concern, not impossible.

[Hammer]

I would still rather have a spool on ice then a locker. That engagement is the killer.
Of course it's darn fun when you plan on it!
I agree with what you are saying. But how often is it? IF the person uses the old brain pan, things will be fine.
I wouldn't drive a locked vehicles nearly as fast as one with open or limited slips on ice. But that is a good thing. Momentum is the biggest factor when dealing with ICE.

[Stuka]

I was refering to driving on the roads. And I live in the moutains, no flat or straight roads here. I can change 4000ft in altitude oing from town to work in a 11 mile stretch. We get lots fo ice and a good amount of snow, and we do not use salt here. Been driving in the stuff for the past 7 years using 4wd's with locked rear axles (detroits). Never once have I had them wip out on me or get squirly. Now a spool is easier to drive in snow and ice, but so long as you know how to drive, a locker is a non-issue.

[FSJeeper]

Originally Posted by Stuka

I was refering to driving on the roads. And I live in the moutains, no flat or straight roads here. I can change 4000ft in altitude oing from town to work in a 11 mile stretch. We get lots fo ice and a good amount of snow, and we do not use salt here. Been driving in the stuff for the past 7 years using 4wd's with locked rear axles (detroits). Never once have I had them wip out on me or get squirly. Now a spool is easier to drive in snow and ice, but so long as you know how to drive, a locker is a non-issue.

Stuka, man, you live in paradise and you have more experience than most with lockers.

I have a lot of experience with lockers but only a little on snow and ice.

A rear Detroit is totally liveable on the street, esp. with our FSJ's. You just have to change your driving habits or it will get you. Decellerate in turns, slowly acclerate coming out of turns, otherwise it will engage on the turn and give you a surprise. You have to drive deliberatlly and always keeping mind it is back there or it will surprise you. Any quick lane changes under accleration will kick it in. Just be mindful of how it acts and you will be fine.

That said, the ultimate solution is selectable lockers because open diffs are superior on the road. After that, and for your application with limited road driving, I would go with a spool. Bulletproof and totally predictable. Yes on the street you'll squawl the tires in turns but it is not that bad. You'll also have more tread wear on the street.

I agree with Hammer on the front, a posi would work perfect. You only need a full locker if you spend a lot of time with one wheel in the air.

2 years ago I went to Nor Cal in my Dodge truck which has a tight posi in the rear with a trailer. I was caught in a bad snow storm coming back over Shasta mountain and took a "short cut" to utah on a very small road to get off the mountain. I did not enjoy the posi at all under these conditions. I am not experienced with lockers on ice and snow though so maybe I am a wussy. I was raised in areas it snows a lot and went to college in Colorado and owned a FSJ then but all of my prior snow and ice driving was with open diffs.

For me and my new crewcab FSJ project, the front axle will be selectable and if I can get a selctable locker for the Dana 70 rear it will be also.

Also agree, do the rear first, it does most of the work.

[Stuka]

I will have to disagree on the LSD up front for use in the snow. You rarely have enough traction for the LSD to differenciate between the two axles. This can lead to crab walking and sliding sideways in snow and ice. I have never put an LSD in the front of any of my axles because of this reason. Its very undrivable.

As for towing with a locker, I advise against it. Braking can become very dangerous on corners. The trailer will want to push the *** end out sideways, and it becomes very easy to jack knife.

And LSD in the snow will act the same way, not enough traction to differenciate so it acts like a locker. I am going to assume that you took either HWY 97 or HWY 89 to get off i5. Thats a really bad area to be towing a trailer in the snow. i5 gets a ton of traffic on it from skiiers which results in wrecks all the time on that stretch of road. And the roads going off it to the east are not that great either. I can see why you did not enjoy that drive.

EDIT: Oh yeah, a detroit or similar style automatic locker in a FSJ is not nearly as quirky as it is in a shorter wheel base vehicle. Lockers can be death traps in CJ's and the like, especially when shifting a manual trans. The longer and wider stance of an FSJ makes them much more managiable. I know the detroit in my J10 is practically invisable to m when driving on dry pavement, I rarely notice its there. In the cherokee it was more noticable, but it was an NT with a 10" shorter wheel base. But like mentioned above, you need to know its there, and respect it. If you do this, you should not have any issues. I should note that I add a few hundred pounds of weight to the back of the J10 in the winter, because with nothing back there it is very light. This was not needed in the Cherokee, as it weighs 800lbs more than the J10 does, most of which is in back (roof, glass, tailgate).

[TINMAN93]

I think that the diff selection must reflect the user more than the function. Posi's have their benefits and backdraws on the snow, and especially ice. Open diffs are more forgiving when steering, but have their weakness for traction. The old trick I learned in the snows of new england was to gently apply the park brake to equalize the torque in the rear axle to make a poor man's posi, to say. The front is best open in the slipery stuff. I agree that any kind of locker in the front is great for wheeling, but can be a real handfull on snowy streets. As far as wheeling, I use a Quicklock in front with lock-out hubs which gives me great offroad traction and saves parts by unloading in bad spots. True, I never lock the hubs on the street, regardless of the conditions because I have an OX out back that gives me all the traction I need in two wheel drive on the streets. Now, when I've had to rescue the snow bound car, I can still lock all four to pull them to safety. On the trail I believe a selectable locker is best, be it an OX or an ARB. I find that tight turns are much easier with the rear open, and front locked. I rarely have to three point like my friends ZJ. I do have plans for cutting brakes, budget cable type, which should make the short Jeeps wonder how I make those turns. And just for support, never tow anything with a locker engaged. Expensive!
Tinman

[TINMAN93]

I agree that street driving in snow with lockers can be a handful. I believe that the choice of diff should reflect the driver more than the function. I run a Quicklok in front and an OX out back. With lock-out hubs I only engage the front when on the street to rescue those silly cars from the snow banks. With an OX out back, I really don't need 4wheel on the streets often.The selectable locker gives me the stablility of an open diff on the streets and the ultimate traction offroad. It's always easier to steer with only one tire per axle spinning. I also find offroad that I can turn a lot sharper with the rear open and front locked. Even tighter that my freinds ZJ. There are a lot of choices so be honest with yourself on how you are really going to use your Jeep, and then buy the best parts you can afford. It gets really expensive doing it the second time. This is also the time to choose your gears because carriers are differrent below and above 3.73's, usually. Again be honest and slow about making your choice. The right set up can make driving your SJ on and off road a blast, or *!#<! headache.
Tinman

[rockkrusher79]

Originally Posted by shimniok

Rear only because it will be easier to steer off-road and you can run 4wd in case it rains/snows without sacrificing steering. I ran with just rear for years in two FSJs and was well pleased. The front ARB doesn't do a whole lot in most cases to be honest. At least that's my assessment so far. I'm sure I will find situations where it makes a night and day difference.

Can you say Mt.Blanca? You will definatly like that ARB up there.