Lowering the Transfer Case on a Jeep Cherokee

Lowering the Transfer Case on a Jeep Cherokee

One common method to deal with drive shaft vibrations on a Lifted Jeep Cherokee is to lower the transfer case one inch to reduce the drive line angles. The pinion is rotated up slightly by using longer shackles or axle shims.

While there are various transfer case lowering kits available in the after market and even one from the Jeep dealer, they all serve the same function: they space the cross member down one inch from the unibody frame rail.

The spacers can be made in a variety of ways. On simple way is to take a piece of 1 inch square tubing or bar stock and drill two holes in it. Another method is to use a stack of washers or a piece of pipe cut one inch long and wrapped around each mounting bolt.

The original mounting bolts must be replaced with longer bolts and the two mounting studs must be removed from the frame. Normally these are replaced with bolts as well.

Bolting a dropped cross member into place can be a challenge. As the transmission engine unit drops it tends to move to the right. Without the studs to align the cross member, it is necessary to hold the cross member in place while starting the bolt into the threaded part of the frame. Because the bolt is now one inch longer, it is easy to cross thread it.

Also, since the cross member hangs down further below the Jeep it is easily impacted by rocks and other obstacles. It is possible to bend the nutsert in the frame making it even more difficult to get the bolts started once the cross member is removed for any reason.

One solution to the bolt problem is to make a longer stud instead of using four long bolts. This will help align the cross member when it is being installed and reduce the change of cross threading. If the nutserts are damaged, you may have to cut into the floor and install a bolt form the top of the frame. Alternately you can weld in a stud from below.

Another problem with the lowered cross member is the angle of the exhaust. The down pipe from the manifold is bolted to the cross member. As the cross member drops, the catalytic converter and the muffler will move down as well if nothing is done to compensate in the exhaust system. The pressure put on the hanger behind the muffler will exceed the strength of the rubber hanger. Also the increased pressure will cause the muffler to crack where the tail pipe exits over time unless the exhaust system is modified.

Having the transfer case sit lower also puts an extra strain on the transfer case shift linkage. If the transmission mount is worn the linkage can slip out of the body mount during off road flexing. When this occurs, the transfer case will not shift from 4wd to 2wd until the linkage is replaced in the bracket.

To eliminate the need to drop the transfer case, a Slip Yoke Eliminator kit is available for the transfer case and when used with a double cardon drive shaft, the transfer case can be used in its original position. See How to install a SYE for more information.

UPDATE: I noticed that the transmission mount for the five speed is about an inch thinner than the one for the automatic. I have not tried it yet but it looks like you could use a manual mount on an automatic to achieve a 1″ drop without lowering the cross member.

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How to replace the track bar on a Jeep Cherokee

How to Change the track bar on a Jeep Cherokee

The track bar locates the front axle side to side on a Jeep Cherokee. The stock bar consists of a rubber bushing at the axle end and a tie rod end at the frame joint. The frame end joint generally wears out first.

To determine if the track bar is bad, hold your hand on the frame end joint while an assistant turns the steering wheel back and forth. Any movement here means the bar is bad.

To replace the bar begin with the vehicle weight still on the axle. Locate the steering so that the 15mm head bolt that fastens the track bar to the axle is accessible. Remove the bolt. There is a special nut with a tab on it behind the axle. Pull it out after the bolt is free.

Now lift the vehicle to a comfortable working height. Remove the cotter key from the mounting bolt. Use a ¾ inch box end wrench to loosen the nut. Do not remove it completely at this time. Run it up even with the top of the bolt.

Use a tie rod end removal tool to press the tapered link out of the frame mount. My favorite is the pesto tie rod puller from JC Whitney    ( Since that tool is no longer available try this one from Amazon) that accesses the joint from the side. Hammer the puller between the bar and the mount. This will likely damage the rubber boot. Put a moderate amount of pressure on the puller by tightening the bolt on the puller.

Then use a hammer to hit the frame bracket. Hit it hard. The idea is to temporarily deform the tapered hole enough to loosen its grip on the pin. When the bar pops loose, the puller will likely fall so watch your toes.

Remove the nut the rest of the way and remove the bar. Clean the tapered hole.

On the new bar, note the location of the cotter pin hole. Be sure it is rotated in a way that will allow you to put in a new pin once it is installed in the cavity.

Slip the tapered pin into the hole. Tighten the nut. Align one of the castle nut opening s with the hole in the pin. Insert a new cotter key and bend it back over the top of the pin.

Lower the Jeep to put weight back on the axle. Fit the axle end of the bar in the bracket and align the hole. The easiest way to align the hole is to have an assistant turn the steering wheel while you line up the bolt with the hole. Alternately you can push or pull the Jeep side to side to line up the holes.

Slip the bolt in and hold the special nut up behind it and carefully start the threads. Run the bolt in but do not tighten it fully. Bounce the Jeep a few times to settle the bushing in place. Then tighten the bolt.

Grease the frame end joint if it is fitted with a grease fitting.

 

Tie rod removal tool

Jeep 4.0 Oil filter adapter leak

Jeep 4.0 Oil filter adapter leak

Jeep Cherokees and other Jeeps that use the 4.0 are subject to a leak on the side of the block where the oil filter adapter attaches. There are three O rings inside that with age will leak.

Often this leak is misdiagnosed as a rear main leak or even a valve cover gasket leak. When the oil filter adapter leaks oil is blown back and collects on the rear of the engine.

The proper O rings are available in a kit from your local Jeep dealer or form a Crown Automotive distributor. Standard O rings do not seem to fit, so you need to get the proper rings from the kit.

There are two different types of oil filter adapters used throughout the run of 4.0 blocks. One has a 5/8 hex on the surface. The later version has a T60 torx in the end.

Removal of the older hex version is pretty straightforward. Just turn the hex with a wrench and remove the adapter.

Removal of the later Torx version is more difficult in that there is not enough room to put a normal torx bit in the opening and still be able to put a racket on it. One method to gain clearance is to remove one of the bolts that hold the engine mount to the body. Getting this bolt head out of he way will give just enough clearance to put a 3/8 ratchet or breaker bar on the torx bit. As the center unscrews, you will run out of room before the part is all the way out.

One way to deal with the lack of clearance is to use a torx bit that can be fit in a box end wrench. Or you can make a special tool for the job by welding the torx bit into a box end wrench.

When the O rings are hardened, it takes a lot of torque to break it loose initially and there is a lot of friction all the way out until it comes loose. If you make a wrench, be sure to make it strong.

Once the adapter is off the block, you will need to remove the old O rings. If it was leaking, then they will likely be hard like bakelite. The big one often sticks to the bock. Scrape it loose or free it from the O ring groove depending on where it ends up.

The two on the center bolt are best removed using a dental pick. Coat the new ones in oil to slip them in place. Make sure they are seated in their grooves and not twisted when in place.

Set the adapter back up on the block. Align the roll pin with the groove in the adapter to ensure the proper clocking of the adapter.

Carefully start the center bolt into the bock and tighten securely. It does not have to be as tight as it was when it came off. It was stuck by the old O rings then.

Check the oil level, as you will likely have lost what was in the filter. Start the engine and check for leaks.

T60 bit can be turned with a wrench   https://amzn.to/2rrE454

Dick Cepek Crusher Tires on Jenny’s XJ Jeep Cherokee

Dick Cepek Crusher Tires on Jenny’s XJ Jeep Cherokee

In order to get a bit more off road capabilities, Jenny decided to go up a couple of tires sizes. She ordered a set of Dick Cepek Crusher tires from Tire Rack after reading many reviews and considering factors such as shipping time and customer service. To read more about her decision making process see her blog post at: http://thejeeptalks.blogspot.com/2010/11/dick-cepek-crusher-tires.html

The Dick Cepek tires have a very interesting tread pattern in a dog bone shape. The side lugs are in the shape of a skull and cross bones. The tread has a huge void area that makes for good traction in mud and rocks and self cleans quickly. The lugs are also siped for improved wet traction on pavement.

The tires arrived quickly from Tire Rack and were delivered by my friendly UPS driver who was kind enough to off load the very heavy tires in front of the shop door.

Mounting them on the rims with my manual tire changer proved to be a challenge due to the heavy sidewall construction. It was difficult to compress the tire enough to get it to slide into the drop groove on the rim. In fact, we got only three mounted before the concrete anchors that held the machine to the floor failed. I had a local tire shop do the last one and I noticed even his fancy pneumatic tire machine had a little trouble pushing on the last part of the bead.

While I was mounting the tires, Jenny worked on opening up her fender wells to accommodate all that rubber. The stock flares were removed and the flange was folded under to make a smooth surface in case the tires did contact the body work.

In the front, the bump stops were also extended an inch and a half with spacers mounted to the bottoms of the coil spring perches. The tires looked great mounted on her black Cragar steel wheels.

On the road the tires are surprisingly quiet. The road feel is fantastic and they are very smooth running. The tires required very small weights to balance which surprised me considering the total amount of rubber on them.

On the trail, they showed their value right away. She first aired them down to 15 psi. They did a fantastic job of getting her up the very muddy class III and IV trails in Harlan, Ky. The sidewalls still looked very stiff over rocks however so on day two she dropped the pressure more to 11 psi. I was pretty sure that as stiff as the sidewalls were there was little danger of them popping off the rim.

In the infamous Lower Rock Garden the tires did a fantastic job of gripping the rocks. The skull shaped side lugs that I had thought were mostly for show gripped rocks like glue. At one point the only thing holding her to a rock was the side lug and as she drove forward the tire went up the rock instead of slipping off. And this was in wet snowy conditions.

She was very happy to make her first successful run through the Lower Rock Garden. The new tires worked great.

Also on one very muddy climb where the only trucks that had made it up ahead of her were running Swampers, she made a quick mud slinging run and made it all the way to the top in one pass. The deep bone shaped lugs dug in and cleared out just as they were needed to make it up the twisty climb. I think she embarrassed some of the guys running BFG’s in that she made it look easy to climb the hill.

As we were leaving on Sunday, she aired them back up to 30 psi for the trip home. Even at interstate speeds, the tires ran smooth and quiet. The Dick Cepek Crusher tires proved to be very tough and versatile. They handled everything she threw at them: rocks, mud gravel and pavement with equal ability. Hopefully the tread life will be as great as the traction and she can enjoy them for a long time to come.

Dick Cepek Crusher Tire

Dick Cepek Crusher Tire

Dick Cepek Crusher Tire priced from $167.






Rear Disk Brake Conversion – Jeep Cherokee

Rear Disk Brake conversion on a Jeep Cherokee

ZJ disk Brakes on an XJ

I converted the rear brakes on my Jeep Cherokee from drums to disks. I used parts from a 96 ZJ Dana 35 to make the conversion.

I removed the brake backing plates, hand brake cables, hydraulic lines, and mounting brackets from the ZJ axle. I also pulled the bracket that holds the cables to the body as well as the brake adjuster and balance bar. The conversion might have been easier if I had pulled the ZJ handbrake lever as well.

Removing the drum brakes from my XJ meant disassembling my Lock Rite locker to get the C clips loose. This is not a big job except that it never comes apart like I think it should and it takes me a while to remember which slot the C clip has to exit through.

When I pulled the cover, I noticed that it had been way too long since I changed the gear oil in the diff. I also noticed that on a previous outing where I had banged the diff cover on a stump, it had in fact made contact with the ring gear. The gear is fine but the cover had a cut in it. I hammered the cover back close to its original shape while I had it off.

With the axles out of the way, the drum brakes came off with four mounting bolts. My backing plates were stuck to the axle with dirt and rust and had to be tapped with a hammer to slide them off the end of the axle housing.

I found that the center hole in the disk brake plate was too small to go over my 8.25 housing. I used a milling bit chucked in my drill press to enlarge the hole so it would slide over. The bolt pattern matched. The mounting studs on the 8.25 are a little too short but there seems to be enough thread engagement. If I ever do this swap again, I will pull the mounting studs from the ZJ axle as well.

With the backing plates mounted, I attached the calipers to the plates. The upper bolt is partially obstructed by the leaf spring, but it went in anyway. I also found that if the bolt is slipped into the caliper before it is set in place it all goes together easily.

I used the hydraulic lines from the ZJ. The line on the left brake was close to the right shape and required only minor bending. The long line to the right brake required quite a bit of re shaping to go over the 8.25 pumpkin and line up with the caliper. It eventually fit. The rubber line from the axle to the body matched up perfectly with the XJ hard line at the body. There is also the advantage that the ZJ line is longer than the XJ line so I don’t have the line limiting the droop as before.

ZJ disks on a XJ 8.25

I used the ZJ hand brake cables because the XJ cables have a different end on them. I removed the bracket from the bottom of the ZJ and cut it in half. I used only the rear half. I bolted the rear half to the floor of my XJ just above where the old cable clips are.

Hand Brake cables using ZJ bracket

I used the balance bar from the ZJ and used the ZJ brake adjuster rod as an extension on the XJ brake rod. I had to add a couple more inches to the rod to make it all connect up.

ZJ hand brake cable bracket

Once diff was refilled with gear oil and the brakes bled I mounted the wheels. One thing I had over looked was that the rotors are enough thicker than the drums to make the lugs bolts too short. I will have to replace these as they need another thread or two to be fully engaged with the lug nuts. If I had closed end nuts I would never have noticed.

Stopping power is vastly improved over what I had because I had a leaking wheel cylinder on the drum brakes. I used the original proportioning valve.

It took several adjustments to get the hand brake tight enough to hold on my steep driveway. However, once the slack was out of the cables, it held fine. My hand brake has not worked right on the drums for a couple of years so it will be really nice to not have to find trees to brace against when I need to hop out on the trail.