Which gear oil?

[RustyJC]

BV,



I stated that 3 quarts brought mine up to (over) full. You have me worried now. I'll recheck the level when I get home tonight to see if any has migrated or disappeared from the initial fill.



Rusty

 

[Wheaties]

from dodgeram.org



Dana 70:

4x2 7. 0pints (3. 311L)

4x4 7. 75pints (3. 666L)



Dana80:

4x2 6. 8pints (3. 22L)

4x4 10. 1pints (4. 79L)

 

[HEYBOSS]

Done deal

Just got done with diff. fluids change.



Here's what I did... ..... truck was sitting for 8hrs. I made my own diff. dipstick and measured how much I had on front and rear diffs. before the fluid changes.



Truck sitting on level ground rear diff was 1/2' below fill hole.

Front diff. was 8oz overfill



Factory specs according to owners manual was;

rear diff 3/4" + or - 1/4 below fill hole

front diff 1/4 + or -1/4 below fill hole



I have the dana 80 for rear and 60 front.

Rear took exactly 2oz shy of 4qts which is almost 8 pints.

Wheaties is right about the book specs which calls for 10. 1 pints, but this was the actual amount I came up with.



Front took about 3qts level to fill hole.



Royal Purple rocks, didn't need any modifier. I had a short road test with truck and some tight turns and can't feel the difference between the fluid changes.



Now the rear diff. fluid was dirty and black while the front didn't look like it needed a change, it still was clear. I have 22k on truck right now.



So far I'm happy with the Royal Purple and saves the hassle for adding modifier. For the front axle I used the recommend 80w90 gear oil which I used Castrol. I felt there wasn't a need for synthetic up front.



One little tip I picked up from Tdr was to jack up the rear end on one side at the time to drain the fluid from the axle tubes. I must admit I was amazed how much more fluid drained from the axle. Good tip and recommend it to all.



Fred.

 

[amsoilman]

Its true what DonM is saying with regards to heavier lubes in general will carry a bigger load, however, the Base Stock the lube is made from will also have a BIG part in determining the load carying abilities. If you are using a Synthetic lube with GroupIV (PAO's) as the the base from which the lube is made from, it will indeed have a much higher load carying ability. Example:A Group I or Group II base stock will roughly carry 750 PSI, while the Group IV PAO's will cary Five times the load.



My . 02



Wayne

amsoilman

 

[DocStressor]

Wayne raises a very good point. The advantage of PAO base stock synthetic lubricants over conventional lubes is actually much greater in load bearing gear applications than for motor oils. The EP additive package is also more important. This is one application where 4-ball wear test data actually have something to do with real world results. Before XW-140 synthetics became generally available, lots of people had great results towing heavy loads using 75W-90 synthetic lubes with the Dana 80.

 

[Joseph Donnelly]

It is perhaps interesting that LE607, a petro-based lube, seems to perform very well in tests, as shown to me by Kevin Dinwiddie. It also does well on the dyno compared to synthetics

both Amsoil and LE will be represented at May Madness. This would be a good opportunity to gather information.

Most likely, a good lube that is fresh is better than something that has been in the differential for a long time. Many failures can be traced to old, broken down lube or lack of lube.



A true story: I know of a person who services and rebuilds air compressors. Almost all failures came from no lube in the unit--the owner just hadn't checked for too long. So, when asked what is the best oil to use, he says "oil. " The esoterica of additives, viscosity, etc. have been less important in his field than the presence of some oil to begin with.

 

[C Schomer]

Most people don't realize how hard recip compressors are on oil. It breaks down and cokes up the valves. I change ours every 1k hrs. I'd like to see more on the LE607 but for now, I'll stick with the RP stuff. The RP Syn 15w40 is doing better than the LE8800 15w40 in my engine and the RP 75w90 Maxgear did better than Ams 2k 75w90 in my diff. Temps are still high when I run hard so I just switched to Maxgear 75w140 - available in qts now $7. 22/qt. by the case. BTW, high oil level, on the contrary doesn't make seals leak - it keeps them from burning up. I ALWAYS used oil seals on my OTR trucks and 90w as opposed to grease seals and packing. Grease seals are ancient history! When the seals fit right and bearings are adjusted properly AND the lube is high enough, there's no problem. Look at all the OTR trucks with the front axle covers that have the rubber plug in the center - they're running oil, even in the front. Craig

 

[Cooker]

Originally posted by C Schomer

The RP Syn 15w40 is doing better than the LE8800 15w40 in my engine and the RP 75w90 Maxgear did better than Ams 2k 75w90 in my diff.

Can you elaborate on how you have some to these conclusions? Oil analysis? Can you please provide some details?



Thanks,

Ryan

 

[pwknapp]

I was told by Zimmer Gears owner that synthetic gear oil will "trap air" because of the uniform molecule size versus dino gear lube. Also that dragsters and other race vehicles use dino just for this reason. Is there any substance to this??



Last time I changed rear fluid and added synthetic with a hand pump I did notice a lot of foaming when trying to clear out the last of the oil from the pump. No such foaming even with the old dino gear lube. Both were 75/140. Just my driveway science.