Installing a Slip Yoke Eliminator (SYE) in a Jeep Cherokee

Installing a Slip Yoke Eliminator (SYE) in a Jeep Cherokee

This weekend I installed in Jenny’s Jeep Cherokee the SYE equipped 231 that I built last fall. Our plan was to use a stock front drive shaft in the rear and to remove the transfer case lowering blocks that had to be used to align the drive shaft previously.

Before I began, I coated my hands with Market America Clear shield.

I began by removing the original transfer case. As described in a previous article I installed the SYE in a spare 231 case. The Slip Yoke Eliminator kit can be installed with the transfer case still in place under Jeep.

I began by draining the fluid from the transfer case. Then I removed the rear drive shaft and disconnecting the front shaft from the T case. To remove the transfer case, I supported the transmission and dropped the cross member. I also disconnected the exhaust that the cat flange to get a little more working room.

Next I used a 9/16 box end wrench to remove four of the six bolts that hold the transfer case to the transmission. I used a socket and long extension to get to the two behind the linkage bracket.

With the old transfer case out of the way, I put the modified case up. I had an assistant turn the output shaft to align the splines while I pushed the case into place. Then I tightened the six nuts that hold the case in place.

I lifted the transmission back into place and reinstalled the cross member. Next I reconnected the exhaust and the shift linkage. Then I filled the case with fluid.

The trouble began when I went to hook up the rear drive shaft. The shaft that I had pulled for this purpose would not reach. It was simply not long enough. It also had trouble sliding on the slip joint. So, I rummaged around the barn and found another front shaft. This one slipped in and out easily and reached just fine.

We bolted up the front shaft and took it for a short test run. A very short test run. As soon as we backed it out of the barn, it was obvious that the advice we had read in an internet forum about what shims to use was completely wrong. The drive shaft angle was completely wrong.

I made a few measurements and found we needed 7 degree shims. A call to our local 4wd shop revealed they did not stock them. We chased a few leads they gave us only to find dead ends. As we were ready to give up for the day and possibly the weekend, Jenny used her new Droid phone to research and found Summit racing, 142 miles away, had them. She called and found they had six and eight degree shims in stock but no sevens.

I expected our trip to Golden Mountain was postponed again, but she jumped in my truck and was waiting for them to open the next morning and had shims back at the shop by noon. Determined to go off roading this one is.

I unbolted the spring pack and installed the six degree shims. With it all back together and better aligned, we took it for another test drive. Much better, but there was still a nasty vibration.

Back in the shop I found that the shaft I had grabbed had a lot of play in the double cardon part. So we swapped her front shaft to the rear and made a test run. This time it was vibe free.

I hammered the other shaft apart and greased the splines to get it to slide. Once it was flexible enough I installed it in the front. A quick test run showed some noise but the vibes were at an acceptable level.

Monday we packed up and drove 111 miles to Golden Mountain Off Road Park in Sparta, TN. She had no problem going seventy miles per hour on the interstate following me with my rig on the trailer.

The SYE equipped Jeep handled very well on the trails. Jenny enjoyed the extra clearance that she got from removing the spacers as well.

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Reinforcing XJ control arms

The lower control arms on my off road Jeep have taken quite a beating. I have considered going with after market control arms, but for now with just a three inch lift, I am sticking with the stock control arms.

My first modification to get more droop was to modify the axle above the control arm mounting points. The mounting plate for the shock and spring hits the control arm at full droop limiting the flex. I simply hammered and ground away a lot of the offending material. It adds no strength to the axle and is just in the way.

The other part of the control arm that gives me trouble is where the front axle end bushing is pressed in place. The arm is just folded over here and when hit, it tends to crush and allows slop in the bushing.

When changing the bushing, you have to place a piece of metal in here to keep the arm form crushing while pressing the bushing in or out. To strengthen this area, I cut a length of pipe the size of the inside of the control arm. About 1 1/4 inch. I then cut this in two to make two C shaped pieces. I then hammered these pieces inside the control arm over the bushing. I then welded them in place.

These braces will prevent the control arm form crushing and hopefully prevent some of the bushing damage that occurs when I hit the control arms on rocks.

I also fabricated some guards over the axle mounting points that will further protect the front of the control arms.

After bending one of my control arms at Wooly’s Off Road park, I decided to strengthen them in the bending direction as well. I did this by cutting a piece of 3/4 in ch pipe and placing it inside the U part of the arm. I have seen people plate the bottom but this would keep the arm form twisting. The twist allows the suspension to flex more. To add strength and still allow twist, I drilled three holes int he top of the arm and plug welded the pipe to the arm just at the top.

The pipe should add strength to the bending vector but still allow the arm to twist as designed.

I look forward to seeing how these low buck modifications perform of the trails.

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