|1997 Jeep TJ Wrangler Rear Axle Rebuild.|
Car: 1997 Jeep TJ Wrangler 4.0 Sport
Rear Axle Rebuild Page 1 Page 2 Page 3 Page 4 Page 5
Having removed all the old bearings from the diff, it was now time to fit some new bearings, and begin the long install process...!
The bearing on this side was knocked on and is now permanently fitted.
Two bearings were purchased for this side.
One will be used to set the diff up, before being swapped last minute for the permanent one.
The bearing that will be used temporary has been slightly sanded on the inside so that it can slip on and off as and when required.
Installing the diff with a slip-fit bearing on it, allows you to take measurements, to enable you to work out the thickness of shims, because the shims required on this side of the diff should be fitted underneath the bearing! Using a slip fit bearing allows you to make changes to the thickness of shims used, before you fit the permanent roller bearing much later on!
The outer bearings are fitted. But not the ring gear.
The diff is put in position.
The ARB air locking pipe does not need to be tightened on at this stage, but it is very important to be careful each time you lift the diff in and out as you do not want to cause any damage to this pipe.
The first calculation to take is that of the total movement side to side, and so the diff was levered one way...
...and then the other.
This movement from side to side was then measured.
You should measure to the same point on the diff. It may look like we have not, but this was now the second or third time we were measuring the side to side movement hence why we were using different points. Never just take 1 measurement, always check, and double check!
After removing the diff, get out the new ring gear.
Fit the new ring gear to the diff.
Install the diff again.
This time it will not move as far from side to side as before and by taking more readings of how much side to side movement there is, you should now be able to calculate the approximate thickness of the shims required on each side of the diff!
Remove the diff and fit the shims on either end of it (in the correct places).
This is where having the slip-fit bearing comes in handy, please note is is continued to be used at this stage and goes back on again.
After trial fitting the diff with some shims, more measurements of movements were made and alterations to the thickness of shims used, where made as necessary.
Once all the free sideways play in the diff appeared to be taken up correctly, and yet still with the ring being able to rotate freely enough at the pinion, you then need to check the contact the ring teeth are making with the pinion teeth is correct. To do this you need to apply some sort of temporary paint or paste and then follow the instructions provided that were provided with the ring & pinion as to what adjustments need to be made.
The wear patterns will help to tell you what changes are required for a better fitting.
The thinned down paint we were using was a little difficult to read and so we also tried some engineering paint/ink!
We then went back to another mix of paint. The diff had been in and out a few times by now, and altering the lower shims on the pinion gear each time as per instruction sheet.
We had now got to the stage where we needed to measure the free rotational play or kick was within the prescribed limits.
The kick measurement was taken by measuring up to 1 of the teeth, and then seeing how much the ring rotated and measuring again, and just subtracting one from the other. as always do the measurement at least a couple of times and to different places on the ring to ensure accuracy of the measurement.
Using more paint was now showing the central wear patterns on the teeth that we had been looking for.
We were happy now that we had the settings as close as we would get them.
Next the tension on the pinion was set by installing the correct thickness of upper shims now that the correct amount of lower shims on the pinion had been established.
To get the tension correct here the diff and pinion had to be removed several more times, whilst the thickness in the top pinion shims were adjusted!
Finally when a torque reading at the top of the pinion was obtained within the prescribed limits, all of the shims on the diff and on the pinion gear were set!
We stayed towards the lower setting for this reading as when taking a mid or higher setting the movement on the parts seemed just a little too stiff, and we do not want to cause any excessive wear to the parts. This seemed to be the recommended thing to do, when looking into what others had done in this same situation!
If only this was the finish!...
...but as some of you may remember, we only fitted a slip fit bearing on the diff earlier, and that now needs to be changed for the permanent one!...
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