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Dursky 04-29-2011 05:10 PM

4wd, Front Axle
Ok, so my 4lo/hi engage, but only on the rear axle. Front and rear drive shafts turn but no 4 anything on the front axle. No wheel hop when turning on pavement, no grabbing when going up hills, etc...

So after seeing (eyes on it while my wife drove) the front drive shaft is rotating (because it doesn't when in 2 wd, and is when in 4 wd) I assume it must be something in the front axle. I have checked the pneumatic lines running from the pump to the axle and all is good there. What else could it be, the pump itself, the engaging mechanism in the front axle?

Need to fix it soon, will be wheeling down at the beach (supposed to be) in one week. Thanks in advance for any input. It's an 87 YJ 4.2, stock drivetrain and axles. Yes I checked the linkeage and all is good there.

Irongrave 04-29-2011 05:18 PM

CAD system sucks, get a cable system like a posi lock or something like that or get a block off plate a new inner axle seal and a set of shafts from a late model XJ, or TJ as those have the bigger u-joints

Dursky 04-29-2011 05:20 PM

One more thing...
Oh yeah my 4wd light doesn't come on in the dash either. I'm on a super limited budget, but yes I would like to go to a cable system eventually.

Matcheen 04-29-2011 05:28 PM

Probably the vac motor on the front axel. You can: 1, replace it and hope for the best. 2, buy a posi-lock and get rid of the vac. 3, perma lock the coupling with a spring or a perma-lock set up. Or 4, replace the shaft with a TJ axel shaft.

Personnally I went for the spring engage set up. Cheap, easy, efficient, just do a search on the forum, there' lots of info.

Dursky 04-29-2011 05:36 PM

how cheap
How cheap are you talking, ballpark estimate?

Eventually I'd like to pull a set of rubicon axles from a junk yard and sap in but that's for later on down the road.

NAVYCHIEF 04-29-2011 11:33 PM

spring setup around $1.20.

Dursky 04-30-2011 07:37 PM
"Squid", huhum, I mean NAVYCHIEF, I found the thread about the spring install, sounds great, but how bad of a hit will my mpg take on average by doing th espring conversion? I'm getting 17.1-19.2 (depends on the driving that week) right now. It's a DD and Overlander.

Matcheen 04-30-2011 09:57 PM


Originally Posted by NAVYCHIEF (Post 1210814)
spring setup around $1.20.

$1.20 and about an hour or two of your time.

It shouldn't affect your MPG same set up as the TJ, and....How the heck are you getting that kind of MPG!?!?:eek:

NAVYCHIEF 04-30-2011 11:19 PM

WHATTYA MEAN SQUID? LOL i did mine two years ago. no notice of any mpg change.

jakec 05-01-2011 09:51 AM

i engaged mine with a couple tywraps and its been doin fine going on a year or so. i had a posi lock and it sucked too dont waste your money. i just pulled the shift fork out, slid the coupler over to engage it, and put two tywraps on each side to hold it there.

Dursky 05-02-2011 11:05 AM


Originally Posted by Matcheen (Post 1212173)
$1.20 and about an hour or two of your time.

It shouldn't affect your MPG same set up as the TJ, and....How the heck are you getting that kind of MPG!?!?:eek:

I have spent countless hours tinkering with the carb (Zennith) and have all my emissions stuff disconnected. I'm running 31x10.50, and skinny tires make a difference IMO on mpg. When these wear out I'll go 33x10.50's. Additionally, everything has Mobil 1 synthetic fluids, oil, tranny, etc.. Prolongs the life and makes a difference IMP.

Plus I'm very throttle weary, not too much at one time, kind of eak out as many miles as gently as possible (that all goes out the window when wheeling), and I don't run my roof rack on it unless I need it (wind resistance). I'll draft behind 18 wheelers on the highway, and go into neutral when going down sizeable hills.

I gotta make every penny count now that I'm back in college and not working. After graduation and a new job I'll get crazy with the Jeep then.

Just filled up this morning and I avg'd 17.1333... on this last tank.

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