High pinion angle....Keeping the pinion bearings lubed

High pinion angle....Keeping the pinion bearings lubed


Senior Jeeper
Ground up YJ.

Looking to get a CJ
One important consideration when doing a suspension lift is achieving the proper driveline angle. In a short wheelbase vehicle like a CJ. That sometimes means having the pinion on the axle pointing up towards the transfercase at a pretty extreme angle.

The big problem is keeping the pinion bearing oiled. As it is setting way up out of the oil bath. I`ve seen more then one bearing get burnt up from lack of lubrication.

Here is what I did to my (YJ :censored:) That might be of interest to you.

A radiator or engine oil catch can. (Summit, Jeg`s, Speedway etc) Connect it to the vent line on the axle all you need to do.

The can allows you to over fill the differential insuring that the pinion bearing gets lubed. The fluid heats up, expands and dumps into the can. As it cools it flows back down to the diff. Works on the principle of a radiator overflow tank.

With this I am able to run an extra 1.5 quarts.
Good advice.

Adding more oil helps and you have a good idea to prevent loosing oil out the vent.
Let me add a couple notes on drive line angles.
If the U Joint angles on a drive shaft are not strait (they never are on an off road vehicle) then they actually speed up and slow down on each rotation. This can produce a bad vibration. But a drive shaft is made so the vibration of the front U Joint cancels the vibration of the rear U Joint. This works great if the the angle of the front U Joint to match the rear. This is how every manufacture makes vehicles.
But this only works at small drive line angles. The UJoints don't like too much angle so when you lift your jeep you may have to angle the rear differential upward. This can be done with angled shims at the leaf springs. Then to keep both u Joint angles the same you can lower your TCase. If the drive line angles get to be too much you should then go to double cardan joint or a CV joint at the front of the drive shaft. A double cardan joint is 2 U Joints together.

These 2 U Joints cancel each others vibrations. In that case the U Joint at the differential should not have any angle. To keep it from vibrating it should be strait like this.
Now you can see how the pinion is much higher than the manufacturer intended.
That vent reservoir is a good idea. Thanks for the tip.
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Both posts...Good advice.

Driveline 101 doesnt really get any simpler then that folks. :cool:
Glad that your ring & pinion set are in tact as of the moment. But if you need to change it up, brands like alloy usa and the like can definitely compensate all the needs in order to really have a good job on your vehicle. Hope that everything is fine by now.

thanks guys :chug: good info.
Sorry about that, but I just wanted to really say that things are now okay in terms of this one. I hope that everything is well after it. But for the long run, I think its all good by now.


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