Migrating Gear Lube

We have a modified ’31 Buick 8-60 Racer that we acquired about 6 months ago. Gear Lube keeps moving from the differential to the transmission. I just drained about 20 oz. off the trans. And will have to add about the same to the rear end.

We have probably only put about 300 miles on it since we acquired it, but we are not sure just how much lube might have moved prior to that. Documentation provided with the car indicates that this was an ongoing problem.

My Specifications and Adjustments Manual does not show any seals in the enclosed driveline. It does appear that the engine may have been lowered in the frame, which would have decreased the angle of the driveshaft.

Has anyone else had this problem? I am thinking of inserting a seal along the driveshaft to stop the flow. I do have to tear down the diff to change the gearing.

Any suggestions would be greatly appreciated.

Pat

some modified fords have this issue I think they fit a baffle in the torque tube. Sounds like it might be a good idea to check the angle of the drive shaft and see if you need to re adjust the angles while your at it.

Thanks Roger_Roy:

The driveshaft does slope to the differential; just not as much as a stock Buick. A baffle would probably work just as well as a seal; just need to slow the flow of the gear lube!

Pat

Can't you use the same lube for both? I do....

Hi Mark:

Yes, I do use the same for both. The problem is that I end up with too much in the transmission and not enough in the differential. Neither of which is a good thing. You would think it would flow back downhill into the rear end, but it doesn't. If I could only figure out the physics of this I could probably build a perpetual motion machine;)

Pat

I think we may have figured it out. This car has a very short wheelbase (109"), therefore a very short torque tube. The engine was dropped a few inches, but the driveline still slopes to the differential.

The churning of the ring gear throws gear lube all over the place (as it should), past the pinion bearings and into the torque tube (to keep all the bearings lubricated). Any time you head down a steep hill, or stop quickly, the gear oil "sloshes" up the torque tube. that would normally not be a problem, however, with such a short torque tube, it can reach the U-joint.

Now here is the big part! The U-joint slip-yoke spline rides in a bronze bushing. The bushing has a spiral cut groove to allow allow transmission oil to lubricate the bushing. The U-Joint slip-yoke spline has a spiral cut groove the opposite direction, designed to "pump" the transmission oil back to the trans, and completely lubricate the bearing in the process.

The problem is any differential lube that makes it all the way to the U-joint is picked up by the slip-joint spiral and fed into the trans.

Amazing how much gear lube this will pump in a short time!

Now for a solution:confused:

One possibility is to weld up the groove in the slip yoke. The bushing would still get oil, but we could end up overfilling the differential!

A second possibility is to make a sleeve that fits in the torque tube to dam the movement of gear lube.

A third would be to make a sleeve, and add a neoprene seal.

Thoughts?

Pat