Rear end gear lube

[gfigms]

I got one of those phoney quick change rear end covers for by JAG in the T-Bucket. It had a small vent tube on\in it and it was blowing gear oil out at highway speed. I pulled the cover back off and had a baffle tack welded over the vent hole on the inside, but still it blows gear oil out. Changed the vent out to a fitting and put a piece of clear plastic line from the fitting towards the ground. It still blows oil and leaves a puddle of gear lube. Someone told me to change over to full synthetic gear lube and it wouldn't foam anymore. Any truth to that? ... any experience with the same problem? ... and how did you fix it?

 

[Screaming Metal]

Well, a modern synthetic gear oil should not foam. Weither it be a motor or a gearbox or a differential, for the bearings to be lubed correctly, a steady stream of oil, or bath, not foaming should be utulized.
If you have a sufficient vent tube diameter, a anti-foaming synth gear oil, a adaquate vent baffle, there shouldn't be a siphoning effect. Have you checked your Pinion seal?

 

[Mike J]

Is it overfilled? That will cause that.

 

[T-Test]

Try running the vent tube up to the chassis with a vent cap like on 4x4 trucks do to keep water out.

 

[2old2fast]

I've heard mention that some of those aftermarket covers the "vent tube" can be lined up w/the ring gear , & in such cases the ring gear is throwing lube directly at the vent causing the leak . Second hand supposition but could be the case ??
dave

 

[Screaming Metal]

Well, I've seen the loop idea done and it works. On race cars, we do a loop, then we add one of these....keeps dirt out and helps keep fluids in.... Overfilling does help with oil leaking. Usually the vent tubes are on the axle tubes, not in line with the ring gear.
If you ever have to add a vent tube, a good way to add one is to remove your fill plug in the side of the housing, to add a short, threaded nipple to the threaded hole, then with a 90 sticking up, then a threaded barded nipple, short piece of hose with one of these filters.
http://www.knfilters.com/search/product.aspx?Prod=62-1000

 

[Wild Mango]

Those ersatz QC covers that go on the jag pumpkin are terrors for blowing oil. Its because they hold way more lube than the standard stamped steel rear cover. In action the ring gear picks up oil and it is scraped off by a ledge just above the pinion, where it goes to the pinion bearings, who desperately need it. Oil then runs back and is picked up by the ring gear and the cycle starts over - point is, when you're thundering down the highway there isn't any depth of oil in there, its either in a rotating mass about the ring gear, soothing the pinion bearings or running back to be picked up again. The extra lube that goes into the QC cover is just too much and it hydraulics all over the place, pees out the breather and eventually starts seals leaking, the pinion seal first usually. (just like any over filled rear)
If you look at the way the stamped steel cover is shaped, you can see how this process works. I would not recommend dropping the level in your QC cover because the cover is not shaped to channel oil up and over to the pinion bearings.

 

[railroad]

Maybe you can sandwich the stamped steel cover with the fake quick change. You know it can be done, just whether you want to spend the time. good luck.

 

[gfigms]

Maybe you can sandwich the stamped steel cover with the fake quick change. You know it can be done, just whether you want to spend the time. good luck.

That is a great idea! ... I am going to try that.