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Newb dummy question: Is xj really a 4x4?

K

klonestar

NAXJA Forum User
Location
White Mtns. New Hampshire
When in 4x4 does all 4 tires work? I vaguely recall many 4x4's are actually 3x4's (three wheels drive)

Checked my rear D35 and back tires spin opposite so it is a limited slip? I did read all the posts on what percentage goes to front/rear in different 4wd set up. Does limited slip mean only 3 tires working at a time?

Its a stock 90' xj so far. 4.0 auto

Thanks,
Ken
 
Without a traction assisting device in the front and back in 4x4 most are actually 4x2 (4 driven by 2) with one wheel on each end driving the vehicle. Of course that's assuming a slippage somewhere.

Sarge
 
It works well as long as all four tires are on the ground!

If you have an automatic tranny version, you can apply light brake if one tire is off the ground and it will help the other tire that is on the ground to get traction (sometimes).

Still, a locker in both front and rear will provide the best amount of pull.
 
when the tires spin in opposite directions when freewheeling, it means you have an open diff, no LS or locker. with either of those both would spin in the same direction.
 
klonestar said:
So means what? My 4x4 is a 4x2 yes? Bummer! Gotta get that fixed!

Thanks,
Ken

startin to miss my old 74 chevy true 4x4! posi and locking front hubs.
Click to expand...
know anyone with a welder?:D j/k
 
jeeplvr88 said:
when the tires spin in opposite directions when freewheeling, it means you have an open diff, no LS or locker. with either of those both would spin in the same direction.
Click to expand...
Bare with me im on a major learning curve here....

So with an open differential power goes to tire w/least resistance?

Which is why above items say to brake to stop spinning tire so power will then go to the other side?

Same is true for front D30?

You talking 'tapping' the break pedal or actually quickly laying on it?

thanks again,
Ken
 
creeperjeep said:
Tip: When a vehicle with an open carrier flexes so much that one or more wheels comes off the ground, you can apply the brake and throttle to stop the wheel that's off the ground from spinning and allow the wheel with traction to continue to move.
Warning....Click here to see possible side effects.
Click to expand...
So possible side effect is from hitting the tire w/traction too fast or hard?

My luck I'll do that first time out!:shocked:

Following threads and using search it appears its not a good investment sinking $$$$ into D35 and D30 for lockers eh? (sigh!)

Ok so I got a 360 400hp and a dodge 8 3/4 rear end to start with if I junk my 66' Coronet! (slice n dice) lol kiddin!
 
Last edited:
Differential action is a whole course in mechanical engineering.
But the gist of it is, if all four tires are pointed straight ahead, on an even surface with equal traction it's a 4X. Whenever your turning a corner the outside tire turns more times than the inside (front and rear) and the bias for the differential is to the side with the most revolutions (or the tire that turns with the least resistance). Which is most times a good thing, except when you want maximum acceleration or traction.
Applying the brakes moderatly (and progressively) can help force a portion of the bias to the tire turning fewer revolutions (or with the most traction). Getting the a tire spinning or the entire drivetrain and suddenly catching traction (or braking hard) or decelrating it quickly and a whole bunch of kinetic enenrgy comes to a sudden stop (or slowdown). Something has got to give.
Turning the steering wheel right and left (moderatly) can also help with traction.
Got to remember differential action is dynamic and is changing all the time.
A limited slip will force a ratio of torque to the tire with the most traction (or the fwest revolutions).
Also got to remember, the engineers designed the whole thing for an open differntial and/or a limited slip. Excess torque (or a large portion of it) is gonna be dumped to the tire with the least traction. When it's suddenly dumped to the tire (or axle) with the most traction, things break. In the real world the axles/tires are rarely turning at the same rate and the differential action, acts like a fuse to dump excess torque.
Guys spend years, building a drivetrain without a weak link and rarley succeed.
Even a 2X four wheel drive is better than a 1X 2 wheel drive.
 
A locker in the 30 will be fine. I wouldn't put that money into a 35. JIM.
 
8Mud said:
Differential action is a whole course in mechanical engineering.
But the gist of it is, if all four tires are pointed straight ahead, on an even surface with equal traction it's a 4X. Whenever your turning a corner the outside tire turns more times than the inside (front and rear) and the bias for the differential is to the side with the most revolutions (or the tire that turns with the least resistance). Which is most times a good thing, except when you want maximum acceleration or traction.
Applying the brakes moderatly (and progressively) can help force a portion of the bias to the tire turning fewer revolutions (or with the most traction). Getting the a tire spinning or the entire drivetrain and suddenly catching traction (or braking hard) or decelrating it quickly and a whole bunch of kinetic enenrgy comes to a sudden stop (or slowdown). Something has got to give.
Turning the steering wheel right and left (moderatly) can also help with traction.
Got to remember differential action is dynamic and is changing all the time.
A limited slip will force a ratio of torque to the tire with the most traction (or the fwest revolutions).
Also got to remember, the engineers designed the whole thing for an open differntial and/or a limited slip. Excess torque (or a large portion of it) is gonna be dumped to the tire with the least traction. When it's suddenly dumped to the tire (or axle) with the most traction, things break. In the real world the axles/tires are rarely turning at the same rate and the differential action, acts like a fuse to dump excess torque.
Guys spend years, building a drivetrain without a weak link and rarley succeed.
Even a 2X four wheel drive is better than a 1X 2 wheel drive.
Click to expand...
Gotcha! Makes much more sense now! Many thanks.
Ken
 
Depends what your doing. Wheel it open, break it, throw in a rear D44, lock front/rear. If you want true 4x4, it will take some amount of wallet opening. Or better yet, get a unimog, lift your leg and piss on any trail.
 
ILLXJ said:
A locker in the 30 will be fine. I wouldn't put that money into a 35. JIM.
Click to expand...
Ok and now????:)

So a D44 in the rear before adding mods to the rear? Now if a D30 is smaller than a D35 why is it ok to keep and upgrade it? Guess im asking why not a 44 on the front to? or? I like what your saying because it means less money for me! Just trying to understand why a 30 is ok in the front.

I cant do any major mods for a while but hope to understand and make the right decisions for me when the time comes.

Although I will eventually have a good rock climber first I want to make use of what offroading is readily available to me in my area as this is what I hope to be doing most weekends. More muddy washed out dirt roads and mtn. climbing around here w/tons of streams to cross.

And, any issues locking the front with an open D35 in the rear? I want traction for the type of 4x4 ing I will mostly be doing where I live. I also need to keep it a DD for now.

Many thanks again,
Ken
 
Locking the front and your steering disappears. Even with a limited slip it's slightly noticeable (more so in loose stuff), the more aggressive the device in the front the less steering you have. I had a Unimog with a mechanical/lever lock (solid) in the front and no power steering. It was almost like the steering wheel was in the locked posisiton, my skinny butt just wasn't up to turning it much. And when I did get the wheel turned, it wanted to go straight ahead anyway. Not for the streets.
Even an aggresive limited slip or ratchet locker in the rear can mess you up in the snow or rain. Gas it at the wrong time and you swap ends pretty quick. Most of my wheeling is done on snow or in the mud. A limited slip rear and an open front are my preferance. The traction gains with a more aggresive setup are negated by the lack of control. I use momentum, the right tires and the gas pedal to get me through. I also don't often break drivetrain parts.
 
8Mud said:
Locking the front and your steering disappears. Even with a limited slip it's slightly noticeable (more so in loose stuff), the more aggressive the device in the front the less steering you have. I had a Unimog with a mechanical/lever lock (solid) in the front and no power steering. It was almost like the steering wheel was in the locked posisiton, my skinny butt just wasn't up to turning it much. And when I did get the wheel turned, it wanted to go straight ahead anyway. Not for the streets.
Even an aggresive limited slip or ratchet locker in the rear can mess you up in the snow or rain. Gas it at the wrong time and you swap ends pretty quick. Most of my wheeling is done on snow or in the mud. A limited slip rear and an open front are my preferance. The traction gains with a more aggresive setup are negated by the lack of control. I use momentum, the right tires and the gas pedal to get me through. I also don't often break drivetrain parts.
Click to expand...

So as I do need to keep this as a DD in major snow country Id be better off leaving the front alone and working on a limited slip for the rear? Best bet would be to get a 44 and limited slip for the rear?

Is the known axle breakage (35/30) mostly done in rock climbing?

I mean I can get a one front wheel drive mini van into places in snow and ice that most find unbelievable just by using the methods you mentioned. I do understand the driver part. My dad taught me old school when you didnt have all this modern stuff. He said you want to get over there this is how you do it and we never had a 4wd vehicle! I drove my 66' Dodge year around w/limited slip and it handled great on snow and ice!

Thanks,
Ken
 
I have a 8.25 in the wifes 96 and a 35 in mine, I've never managed to break either one yet. I don't go over a 30 inch tire. The gains from a taller tire are marginal for me, as most of the clearance I need is at the axle (rutted roads). And the taller the tire, the worse the handling, it's a tradeoff.
Though I've had a bit of wear on the 35. New carrier bearings, new spider gears, soon new pinion bearings. The 8.25 seems to be heavier duty and seems to last better (though I did lunch one in a Dodge PU once). If my 35 ever does explode, I'll be looking for an 8.25 or a 44. Or even maybe a dually rear out of a Mercedes 2 ton truck. I spotted one at a junk yard with the right width and a mechanical/ lever locker:loveu:
 
Last edited:
klonestar said:
So means what? My 4x4 is a 4x2 yes? Bummer! Gotta get that fixed!

Thanks,
Ken

startin to miss my old 74 chevy true 4x4! posi and locking front hubs.
Click to expand...
Your Chevy is/was no different(4x2) without lockers.
 
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