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Topic Review (Newest First)
03-22-2012 03:24 PM
Beachcruiser Advantage: about 1-2 MPG (theoretically) when CAFE fuel economy standards were seriously threatening truck/jeep production. Manufacturers had to meet a fleetwide average for the total of their vehicles. 1-2 MPG was a BIG deal.

Advantage to us: you can have a locker up front, drive safely in rain snow & then engage on the trail from inside the cab w/out getting your fancy shoes dirty.
03-22-2012 03:22 PM
DARKSLAYER56 Alright, I think I'm starting to understand. Correct me if I am wrong. Each axle must only spin one tire at a time in order to go well on pavement. If the rear axle was full positive traction it would want to walk around on pavement. This is actually a very good system for on road 4wd although somewhat lacking for off road 4wd use. Does this sound about right?
03-22-2012 02:58 PM
Originally Posted by DARKSLAYER56 View Post
Holy crap! I had no idea. When my old 79 CJ was in 4wd it was "in" auto locking hubs and all. Does anyone understand why I'm perceiving this to be a regression in 4wd functionality? What was the advantage for AMC/Chrysler or the owner to doing it this way?
The vacuum actuator that engages 4wd eventually fails. I just put one in my 89. Some decide to do the aftermarket manual system which yours has. I'm sure it works great. I probably should have just done it that way, but the vacuum system on my YJ works. My 4wd is back. In order to easily know if it's working, shift into 4H and start out slow and then start to turn while giving it gas. You'll feel it grab in your steering wheel. Switch back to 2WD and it will feel normal. You only need about 2-3 mph to tell. This type of 4wd is actually pretty capable without the expense of lockers. You probably don't need them.
03-22-2012 02:40 PM
DARKSLAYER56 Holy crap! I had no idea. When my old 79 CJ was in 4wd it was "in" auto locking hubs and all. Does anyone understand why I'm perceiving this to be a regression in 4wd functionality? What was the advantage for AMC/Chrysler or the owner to doing it this way?
03-22-2012 12:22 PM
Beachcruiser Depends on what your planned use is. Some full lockers can be a bit much to live w/ for daily driving (for some people)...others are a bit less harsh.

Many install quite easily in stock open differentials, other designs require certain gear ratios/carriers. Price can be as low as a couple hundred. Fancy 'selectable' (read: on demand) lockers can be very pricey.

A popular option on our models (for a daily driver) is to put a good limited slip in the rear and a full locker up front (that can be bypassed for street use by disconnecting the stock CAD feature). You'd probably be looking at 500~600 total (ballpark;shopping around) & it's something the reasonably-competent shadetree mechanic with all the tools could do in a long Saturday....depending heavily upon which locker you choose. The ones that replace the stock spider gears are pretty simple.

Be aware that most folks consider locking your stock rear end to be akin to a ticking time bomb. Many swap in an 8.8 ford that comes factory equipped w/ a limited slip differential & 4:10 gears.
03-22-2012 12:20 PM
Peepers Alot. If you have to ask, you probably can't do it your self. Lockers start at $250 and can run up over $1000 per axel. Then you have to add in shop labor, and seeing as they all ready are in there, this is also the best time to regear.

To do it right with a selectable locker, figure at least $2000...
03-22-2012 12:09 PM
DARKSLAYER56 How much work / money is involved in adding lockers?
03-22-2012 11:41 AM
Nubby55 One per axle is the way it came, that's why so many add lockers, that way you can have a true 3x4 or a 4x4, and not a stock 4x4 that's really only a 2x4. LOL
03-22-2012 10:29 AM
Beachcruiser You will only consistently spin one wheel per axle if you have 'open', stock gearing in your axle differentials (provided your 4X4 is engaged). Most YJs did not come w/ any type of limited slip/locker option.

If you can spin one tire per axle, your 4X4 is engaging as designed.
03-22-2012 09:33 AM
Is my 4wd engaging?

My YJ has the manual pull 4wd actuator modded by the PO. I'm having a hard time telling if the 4wd is engaging properly or not. So here is my question. When in 4wd should all 4 tires spin evenly or does my jeep have some sort of limited slip axles? It appears to me that my passenger side is spinning but I can't tell if power is being put down on the left side. Should I just try again in different situations? Is it probable that my manual pull actuator just needs adjusted? Any info will be greatly appreciated.

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