Ring & Pinion Lube

[1320racer]

Been using nothing but Mobil 1 synthetic gear lube for the past 2 decades. Current Richmond Pro R&P in my 9" with a MW "Pro Stock Assembly" 3rd member have 720 passes on them, 60 footing low 1.20s to high 1 teens.

[Jim Wahl]

I never realized how varied the opinions on this subject would be! It seems very much like engine oil. I got 6 PMs and not one recommended the same gear lube. All but one advised to use synthetic though. Now a question from you MoPar guys who use an 8.75 rear. How much lube do you use? The stock rear uses about 2.5 quarts. I have heard several guys say all you need is one quart if you have a spool. My red flag goes up when hearing that because you not only are lubeing the ring and pinion but also the axle bearings. I don't see how one quart would be adequate for that. Am I wrong? Jim


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[Ed Wright]

Your not wrong. If you know Jimmy Bridges, ask him what he found about this. Unlike engine oil levels, it's not a windage thing.

[1320racer]

Originally Posted by Jim Wahl

I have heard several guys say all you need is one quart if you have a spool. My red flag goes up when hearing that because you not only are lubeing the ring and pinion but also the axle bearings. I don't see how one quart would be adequate for that. Am I wrong? Jim


.

yes, you are wrong. Many Stock/Super stock racers run only 1 quart and so do I.

[Dragsinger]

Jim, for most applications the axle bearings are sealed so they do not rely on the gear oil for lube. Check to see if that is the case for your combination.

And yes, it is very common to use 1 - 1 1/2 qts for gear oil. For my Firebird with a GM 12 bolt I run 1 1/2 qts. With our 9" fabricated housing I run 2 qts

[Myron Piatek]

Originally Posted by Dragsinger

Jim, for most applications the axle bearings are sealed so they do not rely on the gear oil for lube. Check to see if that is the case for your combination.

And yes, it is very common to use 1 - 1 1/2 qts for gear oil. For my Firebird with a GM 12 bolt I run 1 1/2 qts. With our 9" fabricated housing I run 2 qts

To elaborate on this, the aftermarket, non-adjustable bearings normally used on Mopar rear ends are the sealed "Green" bearings. The OEM adjustable versions may require gear lube. But I haven't looked at one, much less used one for decades.

[Jim B]

Originally Posted by Myron Piatek

To elaborate on this, the aftermarket, non-adjustable bearings normally used on Mopar rear ends are the sealed "Green" bearings. The OEM adjustable versions may require gear lube. But I haven't looked at one, much less used one for decades.

The Mopar OEM 8 3/4 and Dana 60 axle bearings get packed in grease (like front wheel bearings) prior to pressing the assembly on the axle shaft. There is an inner grease seal in the housing that prevents rear end fluid from reaching the wheel bearings.

[Myron Piatek]

Originally Posted by Jim B

The Mopar OEM 8 3/4 and Dana 60 axle bearings get packed in grease (like front wheel bearings) prior to pressing the assembly on the axle shaft. There is an inner grease seal in the housing that prevents rear end fluid from reaching the wheel bearings.

Thanks for refreshing my memory. At least I got the first part right.
I believe some of the other Mopar axles with c-clips and straight bearings use gear lube?

[tj310]

One of the reasons they put the level so high in a stock rear is so the side carrier bearings are bathed in oil. If you try to run at the stock level you will most likely see leaks as well as an associated power loss . idealy I would run it full to warm up and then drain out all but a litre to race. But that's alot of work and I 've only done it that way once or twice.---Trevor

[Ed Wright]

Might be common, but that does not make it right. I was running one qt in my GM 12 bolt. At Indy last year James Lee was with me. He walked over to visit with Jimmy Bridges. Gear lube came up. James had been galding gears. Jimmy had done some testing on the bench with a clear cover. I don't remember the speed, but at some point all the lube ends up in the axle tubes. He said his was faster with more lube. At that time I added the other qt of lube. To my surprise I picked up almost 1/2 MPH there at Indy. Kept that gain after returning home. You may not believe it, but might want to test it for yourself. An extremely low HP car may see something different, but if it doesn't run quicker low on lube, why do it? Your results may vary. LOL
Btw, I use Royal Purple synthetic gear lube. Never a problem.