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4 wheel drive not engaging???

B

blr_sts

NAXJA Forum User
Location
Northern Kentucky
I'm a noob to jeeps and 4 wheel drive in general but I do have some knowledge of how it's supposed to work. When I pull the lever up into 4 high the part time light comes on and everything but when I hit the wet grass coming up the hill behind my house i do nothing but spin the rear tires. Now my buddy also has a cherokee so I crawled under his and the shaft that comes outta the transfer case up to the front axel doesn't spin freely in 2 wheel drive. I'm assuming thats normal because I know that his 4 wheel drive works great. Now when i crawled under mine that same shaft just spins and spins. Now like i said i'm new to this so i really don't know what's supposed to do what. Any help would be greatly appreciated. Thank you in advance.
 
if it is a vacum actuated axle, follow the vacum lines to the axle, should be near the passenger side top of the axle. verify that the lines are connected at the transfer case and the axle with no cracks or disconnected segments.

is it possible that the previous owner pulled the gears out of the diff. that part time light should only come on if the hubs engage. the front drive shaft should be turrnable by hand when it is dissengaged but should not just spin freely.
 
it is possible that's what the previous owner could have done. he was kinda shady. i'll take a look at the lines tomorrow once its light outside. and yeah the shaft spins pretty easy with 4 wheel drive disengaged
 
blr_sts said:
I'm a noob to jeeps and 4 wheel drive in general but I do have some knowledge of how it's supposed to work. When I pull the lever up into 4 high the part time light comes on and everything but when I hit the wet grass coming up the hill behind my house i do nothing but spin the rear tires. Now my buddy also has a cherokee so I crawled under his and the shaft that comes outta the transfer case up to the front axel doesn't spin freely in 2 wheel drive. I'm assuming thats normal because I know that his 4 wheel drive works great. Now when i crawled under mine that same shaft just spins and spins. Now like i said i'm new to this so i really don't know what's supposed to do what. Any help would be greatly appreciated. Thank you in advance.
Click to expand...

since your new to this, next time post the year, engine, and what transfercase(231 or 242). in this case, it really helps to know because you may or may not have a vacuum disconnect front axle.
 
2HI-4HI-N-4L means you have a 231
2HI-4HI(full)-4HI(part)-N-4L means you have a 242.

being a 91, you should have the CAD axle (Center Axle Disconnect). there should be a small "double pie tin" attached to the rear passenger side of the front axle. there should also be a few vacuum lines running from the unit to the t-case. if these lines are missing or damaged, a simple fix is to disassemble the unit adn shim the shift fork with washers, similar to a DIY posilock.
 
Some '91s still came with the front axle disconnect. My old '91 had it. If it does have an actuator motor on the back side of the axle on the passenger side, check the vacuum lines going to it. If the lines are good, the actuator itself is probably gummed up. This system is really just a pain.

If the actuator is gummed up, do yourself a favor since you'll already have the unit off, shim the fork inside of the unit over so that the collar that runs in between the two passenger side front axles are always connected to each other. There's a few good write-up's telling how to do this if you search. It's pretty basic.
 
Thanks guys. Yeah its the 231. And it does have the vacuum lines and all that on the passenger side of the front axel. I'll take a look at all that as soon as I can.
 
If you have a disco fix it. There is a great thread on a diy posi-loc using a brake cable & lever. I wish I'd known how to do this before I spent $200 on a Posi-Loc. A disco is not a bad deal if you can acuate it manually. It's the vacuum part that's no good. Guys with YJs run 33"s and disco 30s all the time with no problems. It's like half ass locking hubs so you can run a posi in the front. Not as good as locking hubs, but you already have it so just fix it &use it. Just my opinion. If you have a non disco ignore this and the previous post from DDCxj. You probably have a 242 t/c & the linkage needs adjusting. Of course you still might have a linkage problem even if you have a 231. If you have a disco, the acuater is the likely culprit though.
 
Thanks for all the info... I don't know if it will help much but before it went out it was making this loud popping noise coming from the front axle. I talked to one of my buddies and he had mentioned something about the automatic front lockers going bad??? Not too sure what to look for if something like that would be the problem.
 
the loud popping is probably from the 1/2 engaged disconnect. it is simply two splined shafts connected by a collet with splines on its inner diameter. if the collet is far enough off one of the shafts, it will pop from one tooth to the next.
 
cherokee chuck said:
If you have a disco fix it. There is a great thread on a diy posi-loc using a brake cable & lever. I wish I'd known how to do this before I spent $200 on a Posi-Loc. A disco is not a bad deal if you can acuate it manually. It's the vacuum part that's no good. Guys with YJs run 33"s and disco 30s all the time with no problems. It's like half ass locking hubs so you can run a posi in the front. Not as good as locking hubs, but you already have it so just fix it &use it. Just my opinion. If you have a non disco ignore this and the previous post from DDCxj. You probably have a 242 t/c & the linkage needs adjusting. Of course you still might have a linkage problem even if you have a 231. If you have a disco, the actuater is the likely culprit though.
Click to expand...

Link to this thread? Does the brake cable mod basically replaced the vacuum actuation? Even when these two splines are joined by the acuated collar aren't the two axles still connected through an "open diff" ? I don't know much about the Dana 30 Disco.. so forgive me for sounded so ignorant...
 
you may need to check and see if the axle tube is bent. if those two shafts arent lined up, it wont engage. also it may be that the vacuum lines are just plugged...my 86 was like that. I just disconnected both ends and blew them out with compressed air. hth
 
stephenspann27 said:
Link to this thread? Does the brake cable mod basically replaced the vacuum actuation? Even when these two splines are joined by the acuated collar aren't the two axles still connected through an "open diff" ? I don't know much about the Dana 30 Disco.. so forgive me for sounded so ignorant...
Click to expand...

Seriously.. my search abilities must suck.. does anyone have the like to the thread that details the brake cable mod?
 
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