gear oil and amount questions

[mrthieba]

I need a quick answer so I can go on the veterans day run tomorrow. I rotated my rear axle pinion up to go with lift and double cardan driveshaft a year ago. Forgot to add extra oil to get lube to pinion bearing/seal. 1) how much extra oil should be added with stock cover? 2)Will Royal purple 75-140 be compatible with stock 05 Rubicon gear lube? Thanks for any quick responses. Mat

[RAT]

I need a quick answer so I can go on the veterans day run tomorrow. I rotated my rear axle pinion up to go with lift and double cardan driveshaft a year ago. Forgot to add extra oil to get lube to pinion bearing/seal. 1) how much extra oil should be added with stock cover? 2)Will Royal purple 75-140 be compatible with stock 05 Rubicon gear lube? Thanks for any quick responses. Mat

Holy Cow Mr. how high did you lift that thing?
If you have a stock cover, fill until you get oil on your pinky finger when you stick it in the hole and bend it down at the second knuckle. If you have fingers like mine that may be the first knuckle...
As for mixing oils, I'm not a fan. If you can, drain whats in there (some of the Rubi D44s have a drain plug in the side of the diff so you don't have to remove the cover) and replace with the RP 75-140, otherwise get some more of whats in there now. You can overfill the diff a little with no adverse effects, but don't go crazy. The way the oil is slung around in the diff when the gears are rotating gets plenty of oil where it needs to go as long as you have a decent level of oil (refer to finger method mentioned earlier)...

[mrthieba]

It's a 3.5 inch lift. With the front rotated up to be in line with the driveshaft, the fill hole is lower (I know you know all that). Are you saying the stock amount is enough to get splashed up to the pinion sufficiently? I'm not so worried when off road, but on freeway drives is it possible to dry out the pinion bearing? Thanks

[RAT]

It's a 3.5 inch lift. With the front rotated up to be in line with the driveshaft, the fill hole is lower (I know you know all that). Are you saying the stock amount is enough to get splashed up to the pinion sufficiently? I'm not so worried when off road, but on freeway drives is it possible to dry out the pinion bearing? Thanks

Sorry, I just got back and saw this. Even though you rotate the housing, the ring gear is submerged in oil all the time (if the level is correct) so pinion angle in general won't affect the oil getting to the front pinion bearing. It would have to be sitting damn hi for that to happen. You are right that the fill plug will be slightly lower if the pinion rotates upward, but not enough to worry about. Just make sure there is enough oil in the housing to coat your finger as I mentioned and you will be fine.

[mrthieba]

Thanks Rat. Will double check it tonight and roll on the veterans day run tomorrow.

[RAT]

Thanks Rat. Will double check it tonight and roll on the veterans day run tomorrow.

Cool. Have a good time out there.