4 wheel drive grinding

okay so here is my best description of the problem

it only occurs in 4 wheel drive, when the weather presents issues of traction loss(i.e. snow/ice)

when I put it in 4hi the part time light goes on as it should, and when I give it any ammout of gas beyond just a little over idle I hear a loud grinding sound...and the vehicle acts as if it is in rwd only.

so basically, it seems like the 4wd will work when the jeep is at very low rpms..but to be honest I'm not even sure if its working then.

also, when I'm going say for instance 20mph in the snow..if I hit the brakes hard enough to lock them up and slide, I hear the same exact grinding noise.

so basically if I'm sitting at a stoplight in the snow..if I give it a 1/8 or 1/4 throttle it just sits there and spins the back tires while grinding up front.


any ideas??
thanks!

Tranfer case chain is stretched out & jumping teeth.

okay, thanks!!

so are the sprokets and chain easily replaceable?? or would you recommend picking up a used transfer case from the junkyard??

whats easiest??

what is most cost effective!

thanks again for the quick reply.

silent_bob said:

Tranfer case chain is stretched out & jumping teeth.

Click to expand...

Wow! That is scary. But sounds likely. How many miles are on itL The oil should look bad (lots of metal). Sounds like craigslist/junkyard time.

shes got 255k I'll pull it off and check it out.
thanks!

It's not hard to swap in a new chain & it can be done without removing the transfer case.

Whoa, slow down, stop, cease and desist!

First, what year? What axle up front?

its an 88. not sure what axle up front

sorry noob here :dunno:

its a d30 id take the diff cover off first, check your gears(ring and pinion) possibly a busted tooth???:eyes:

If IRC, the '90 XJ have disconnect D30. That mean it have a two piece axle shaft on the passenger side. When 4WD is selected, a vacumn operated collar in the diff lock the two pieces of shaft together thus enabling the front axle to drive/help to drive the XJ.

You should also try to trouble shoot whether or not this is operating properly starting with the vacumn switch on the TC and go from there. I have no experiance with this type of axle. Some with an XJ from this era will jump in here.

Backing up a little, I think your problem could well be the TC. First, verify that the shaft on the TC is going in gear properly do not depend soly on the light. My XJ did that before. A shift linkage adjustment cured it.

Before ripping things apart you could:

Adjust the tc lever.

Check and see if you have the Dana 30 CAD axle. If you have the CAD/disconnect axle you need to test the operation of the vacuum system (prone to failure), the tc vacuum switch, the axle's vacuum motor (also prone to failure).

I would do the above before tearing something apart.

techno1154 said:

If IRC, the '90 XJ have disconnect D30. That mean it have a two piece axle shaft on the passenger side. When 4WD is selected, a vacumn operated collar in the diff lock the two pieces of shaft together thus enabling the front axle to drive/help to drive the XJ.

Click to expand...

My 1990 does not have the disconnect D30, so it might not be his problem.

I'd check the fluid level, adjust the linkage and see what happens. Also, there is a small plastic shift fork inside the t-case that sometimes wears out and causes jumping on some models. I have a 242 in my 1990 and I've had the same problem once or twice...I'm not too sure what was causing it but I cured it with some heavy right foot. It seemed to "pop" back into gear and has always shifted fine since, it just needed (wanted?) a good flogging once and a while.

None of the 242 tc vehicles have the D30 disco, they are only on the 231s.

once again..4x4 noob... what is the tc lever?/ and how would I go about adjusting it??...

tc lever=transfer case shifting lever.

Pop out the bezel--plastic shift indicator with 2wd-4hi-4lo on it. Move the lever fully to the rear against the 4lo shift gate--that would be the sheet metal piece. Place a 3mm (1/8") feeler gauge/shim/drill bit between the rear shift gate and the lever. Hold the lever in place with a bungee cord tight against the feeler gauge and gate.

Crawl under your XJ. From the shift lever a rod runs to the torque bar that is attached from the transfer case bracket and runs across to the body bracket. That upper rod has an adjuster with a bolt. Loosen the bolt. Take a pry bar and make sure the transfer case has fully shifted into 4lo--it doesn't move easily, hence the torque bar. Tighten the adjuster lock bolt. Remove bungee cord and feeler gauge, check and see if 4wd engages.

If this hasn't cured your problem then the vacuum motor (if you have the D30 CAD axle) may not be 1) receiving vacuum or enough vacuum, or 2) the vacuum motor is bad, or 3) the vacuum switch on the transfer case is not working properly.