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How To: Differential pinion mount/bushing replacement

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141K views 113 replies 57 participants last post by  SteveROntario  
#1 ·
How To: Differential pinion mount/bushing replacement for WK/XK

Hopefully this will help other people if they should run into the same problem. I have seen other threads, here and on other sites, but not all of them have the drawing/pics and all the parts and prices.

Well, I started getting a clunk when going from reverse to drive and after searching determined it was the bushings on the front diff that needed to be replaced. There are 2 actual bushings and the other one is an actual mount with a bushing inside and comes as one assembly.

Since I did not know which of the 3 were bad, I just bought all there. Total for all three was about $180 shipped from www.justforjeeps.com (the mount is over $100 alone).

Here is a pic for reference. #1 is the easy one since you don't have to disconnect the drive shaft to change it (just remove the bolts that hold it down). #2 is the other one I could see easily that looked fine. The third is on the top, and I didn't take a pic. I originally just changed #1 since it looked bad and was easy to get to (I was hoping I would get lucky and that would be all I would have to do). Well, it didn't solve the issue, and since #1 was changed, and #2 looked fine, I am assuming #3 is the one that is causing my issues.

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Here is a pic of #1 to try and show the cracking of it.

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And here is a reference drawing showing all three. You need both #14's and #6:

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Here are the parts needed:

1 of these. $107.10
http://www.justforjeeps.com/fraxmobr.html

2 of these. $29.79 a piece
http://www.justforjeeps.com/fraxmois.html

To start off, remove all the bolts from the front drive shaft. There are 6 8mm bolts holding it to the front differential and another 6 holding it to the transfer case. Once the bolts are removed, it needs to be pulled out and set aside. I had to use a rubber mallet to help unseat it, as it was a little tough. A few taps of the mallet is all it took. I let it sit on top of the cross member instead of trying to wiggle it out (I honestly don't know if it will even come out unless the cross member is removed that is there. That was too much work, as it is fine sitting there.). Before you remove the drive shaft, make sure it is marked on the drive shaft and the joint so you know how it was positioned. If it is put in different, it might cause vibrations. Mine was already marked from the factory.

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After the drive shaft is removed and set aside, start removing the nuts and bolts holding the bushings in their mounts. I would do the upper and side bushing before removing the mount on the front of the differential (if you remove the front mount first, it will allow the differential to hang down and put stress on the bolts for the other bushings, which will make it hard to remove the bolts). I also used a transmission jack under the differential to keep it from dropping until I was ready for it to drop.

Here is the rear of the drive shaft and how it was resting on the cross member:
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And the front of the drive shaft. It was resting on the heat shield for the exhaust:
http://img.photobucket.com/albums/v321/99formulam6/JGC/IMG_20111209_145729.jpg

After the bolts from the bushings are removed, and the mount from the front of the differential is off, the entire assembly will be free to hang down and rotate to allow access to the bushings.

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This was the hard part. The bushings are press fit into the housing, and mine we extremely difficult to remove. I ended up using an air chisel to remove it, but even using that was a pain. After the bushing is removed, the new one is press fit into the housing. I used a ball joint press, and it went pretty smooth.

When the new bushing(s) are in, reassembly is the reverse of removal (obviously). To get the nut on the bolt for the upper bushing, I had to set the nut in the socket and hold the wrench up against the bolt hole while using my other hand to slide the bolt in the hole. I had to do it this was because there was no way my hand would fit in the space to hold the nut. I also used the transmission jack to hold up the differential to help line everything up.

Tips:
*I did this on a frame lift and had tools/equipment that the Average Joe's garage won't have (I was able to do this on the Navy base I am stationed at and they have lifts/tools for me to use). I know people have done this with a jack and jack stands in their garage, but there is no way I would do it that way after having so much trouble with getting the bushing out of the mount.

*The drive shaft will have to be rotated to get to all of them, but I also had to have the E -brake on to be able to break the bolts loose, and tighten them when I put everything back together. So you will have to be able to get into the Jeep to put the E-brake on and off.

*The bolts for the drive shaft are 8mm. Having ratcheting box end wrenches will help a lot since the drive shaft kind of angles out around the bolts when it goes into the transfer case.

*The bolts/nuts for the bushings/front mount are 15mm for the bolt and 18mm for the nut (I believe. Don't shoot me if I was wrong, I did this last night and am trying to remember).

*Getting to the top bushing's nut/bolt is a complete pain in the ***. I had to take the wrench and slide it over the top of the differential on the driver's side and was just able to get it on the nut and hold it on by the end of the handle. For putting it back together, I had to put the socket on the end of my right index finger, and slide the wrench in the spot (without the socket on) and put the socket on the wrench while it was on top of the differential. I had to do it this way because once the new bushing was in, the differential did not hang down as low, so the few mm's of extra space I had before, was gone and that kept the wrench with the socket on from sliding up in there.

Here is a picture of how I had to put the wrench. The nut is directly in front of where the socket is:

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Getting the bushing out was terrible. Mine was stuck like chuck. I hit it with a hammer and chisel at first and made little progress after about 20 minutes. Then I got an air chisel and that still took about 20 minutes to get it out completely.

Here is a before picture of the top bushing:

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And an after:

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This was the side bushing (wasn't bad at all):

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Hopefully this will help some people out that have that damn clunk from the front end. Mine start off as just when going from R to D (like when pulling out of a parking spot), but it started to do it more and more while driving. As you can see from the pic, the top bushing was almost split all the way through, so it was good that I finally took care of it.

The dealership said 5-6 hours of labor, and I started around 2pm and finished around 6 or 6:30pm. I did it by myself, so it probably would go faster with another set of hands.
 
#3 ·
Thanks. I looked around for a write up on how to do it before I started, and there were a few threads, but some didn't have pics or the links to the pics didn't work anymore. I am a hands on type of guy and like to be shown how to do things (especially when it means taking apart pretty important parts of my Jeep) so I figured I would take pics as I went along to hopefully help out other people.
 
#5 ·
The hard parts are getting to the bolts and I had trouble getting the old bushing out (other people have not had trouble like I did though). It is pretty straight forward once everything is unbolted. I would guess 5-6 hours though if you do it alone, maybe more if you have to do it on your back. I would prepare for the bushing to be stuck in there like mine was and have the proper tools to get it out, and hope you get lucky and it comes out easy.

Oh, and when you do it, before you take out the bolts, put a jack or something under the diff and take a little pressure off, to help the bolts to come out, and it will keep the diff from suddenly dropping. And since you are doing it on your back, you will definitely need a jack under the diff because that sucker is heavy to try and push back into place while you are trying to line up the holes to get the bolts back in.
 
#6 ·
I wish I had known this a little while back.. the dealership charged $1600 for this. Luckily, I didn't have to foot the whole bill because my extended warranty kindly (sarcasm intended) paid for half of it...
 
#19 ·
Just got a quote from my dealer here in NC for $325. I'm going to take them up on this since I just had shoulder surgery 4 weeks ago and it will be a while before I am under my jeep again.
 
#14 ·
Had it done at a local tire place called, Tire Tech. They also rebuild front ends, suspension ball joints etc. I asked 7 different local shops. only two of them said they would do it, one was at 90 an hour.. and the other 55. A well know transmission shop turned me down, a body shop turned me down, and severl basic mechanics.I informed them that they didnt have to drop the diff. just rotate down on cv axel. Also printed pics off of here to show the diff sitting rotated and able to be accessed.
 
#15 ·
I just ordered my bushings and plan to replace them as soon as they arrive. Looks like a simple job but I'm not looking forward to spending that much time lying on my back under the Jeep. I also noticed oil leaking from the cone at item 17, so I presume my seal (15) is shot.

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#17 ·
I had the dealer fix my front clunk a few months ago. About $500. Which of the three is most responsible for the P-R-N-D clunk? I wanted them to inspect the front diff while they were doing the work, but apparently they didn't do that. I have some grinding in the front that I am assuming is in the front diff. Possibly output of transfer case too? Also have some play on the front drive shaft that I'm not sure if it is normal.




If I just wanted to drain the front diff gear oil and inspect the gears, would I just need to remove the mount #6 and then remove all of the front #4 bolts? Would I still need to support the front diff or would it not drop out if only that front mount was removed.

My grinding is intermittent (mainly on deceleration and most obvious at very low speeds), but I'm guessing that I could see some wear on the gears if this is the culprit.

Thanks for any input!
 
#18 · (Edited)
Thanks so much for the amazing write up, you motivated me to do this myself. It took me much longer than you though, about 10 hours total. The top bushing was in two pieces, completely torn. When I finished the "clunk" was gone and the ride even felt smoother.
Tips from my experience:
1. Be sure to have a big torque wrench/breaker bar for the front drive shaft bolts, they used so much loc-tite it would not break free with a 1/2" impact wrench.
2. Crush the "stop lip" inward on the bushing and use that deformed "lip" to push it out the back (the same way the new one will push in). Use an air chisel!!
3. Getting to the top bushing bolt is ridiculous, I used a deep well socket and a universal. That was the only way I could get to it, I used an impact wrench on the other side once the socket was in place.
Totally worth it though my garage wanted $900 to do it.
 

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#24 ·
I did mine in the driveway and it wasn't too bad. Just a little awkward working on your back sometimes. Mine took me 2.5-3 hours. Not difficult at all though. Don't know why I put it off for so long. I didn't even have to take the wheels off. Unfortunately, that was apparently only one of three knocking sounds I have up front. The second was a tie rod. Still searching for the source of the third.
 
#23 ·
Just did mine....

on the '06 Commander.. Getting it out wasn't the toughest for me....it was pressing the new one in!! The night before I soaked the mount w WD40.. a few good hits with the air air hammer had broke it free then pounded it out. The ball joint press I got from Autozone wasn't quite big enough to work, so I used a length of all thread and some of the bushings from the ball joint kit to get it started. once I had it about 1/4 inch in, then I switched to the ball joint press. It seriously sucked, but it's in and I didn't have to pay the dealer or anyone else to do it!! Thanks for all the great pics and instruction!! :)
 
#35 ·
#31 ·
I purchased the 3 online. The front bushing looked fine but upon close inspection the rubber was separated from the metal bracket. The upper bushing was totally shot and the passenger side was like new.
 
#34 ·
so just as a "helper hint" I used my saws-all and cut out the rubber of the two bushings mounted on the axle, then used the sawsall again to cut through the metal of the bushing sleeve in two locations opposite of each other, be careful not to get into the metal of the axle housing, the saws-all chews through the bushing pretty quickly. After cutting, I used a air hammer and each one of the bushings were out in about two burps of the air hammer. Next i used a ball joint press to reinstall the new bushings. i replaced all three diff bushings in about 2.5 hours using this method, but i had a lift so that helped a TON. That time was start to finish.