Royal Purple Rear Axle Lubricant

[RustyJC]

Since we tow a 13,500 lb 5ver, I wanted to get the factory dino 90W out of the rear axle and get some good ole synthetic hypoid gear lube in there. Dodge/Dana recommend 85w-140 synthetic for heavy towing and then happen to mention that the genuine Mopar lubricant available at your friendly Dodge dealer just happens to meet this specification... . what a coincidence!!



If you haven't looked out there in the marketplace, 85w-140 synthetic isn't sitting on the shelf at every auto parts store. I did find Royal Purple 85w-140 synthetic at a NAPA near our house, so I took out a bank loan (man, that stuff is expensive), bought 5 quarts (gotta have some extra, you know) and changed it out yesterday afternoon. To my surprise, 3 quarts brought me probably 3/8" below the bottom of the fill hole (overfilled by Dodges spec of 3/4" +/- 1/4"). Gotta check the level again today!



Anyway, we went out doing a little driving last night to check things out. Everything sounds good, no LSD chatter (the Royal Purple bottle says that it has LSD friction modifier built in). My question is, does anyone have any experience with the Royal Purple 85w-140 synthetic in this application? Although everything looks great, is something horrible gonna happen down the road because I'm using Royal Purple? (By the way, this stuff isn't purple, it's green - maybe I should sue them for false advertising! )



Rusty

 

[Shrimpy]

Hey Rusty, hopefully redram1, I believe that is is name, will chime in here. He lives in the Houston area and is an engineer for Royal Purple. He should be able to set you straight. If it is not Chattering, you have half the battle won!!!!!

 

[Turbo Thom]

Rusty:

The Royal Purple is good stuff and should work well. I use the Amsoil series 2000 and with a temp gauge in the cover, it works very cool. You will be OK.



. . Preston. .

 

[Don M]

TurboTom,



what kinda oil temps do you read on the gauge and where in the cover is the gauge located?



Don~

 

[John]

Royal Purple

Don't sweat it Rusty, Royal Purple is one of the very best synthetic lubricants on the market.



TDR member DAWG-1 changed out his OE gear oil and added the 85W-140 Royal Purple at the same time he replaced his OE differential cover (with a Mag-Hytec cover) last spring and hasn't had any problems.





BTW, what interest rate did you get on your "bank loan"?

 

[DIESELNV]

I have a question about the silicon sealant for the diff. cover. I found Permatex Ultra Grey RTV silicone sealant. On all the packages all uses were listed except for diff. covers. Is this the stuff I need. It says it is good to 625 F.

 

[RustyJC]

Keith,



The grey Permatex is what I used, and it looks like that's what Dana used as well - the original stuff I cleaned off was grey. By the way, I can't believe how tight they had those cover bolts! Don't they know that overtightening causes leaks?



Rusty

 

[ageorge]

Rusty, what was the Royal Purple number on the jug? They seem to have their own numbering system --- the jugs of it I have seen on the shelf don't just say 85-140 or anything like that.

 

[RustyJC]

This stuff came in 1 quart bottles. The label says Royal Purple Synthetic Gear Oil. Down at the bottom, it says Max-Gear Oil, and below that it says 85w-140. The Royal Purple stock number is 01303.



Hope this helps...



Rusty

 

[paccool]

Rusty,



I'm running the same RP lube in my first gen Dana 70. Had the rear end rebuilt and left the standard lube in for about 5,000 miles to get a good lapping of the gear sets. Then put in Eaton Synthetic with friction modifier and had the limited slip start chattering real bad. Had to order the RP and it took a month to get from a local source. When I changed again, I went ahead and put in a bottle of Dodge additive in the RP. All is working well now. No chatter or noise at all. BTW, I also use RP oil in my engine with a Amsoil single bypass unit installed.

 

[Pit Bull]

Originally posted by RustyJC

Since we tow a 13,500 lb 5ver, I wanted to get the factory dino 90W out of the rear axle and get some good ole synthetic hypoid gear lube in there. Dodge/Dana recommend 85w-140 synthetic for heavy towing and then happen to mention that the genuine Mopar lubricant available at your friendly Dodge dealer just happens to meet this specification... . what a coincidence!!





Rusty

Your 3500 with the Dana 80 comes from the factory with synthetic already in it, (been that way since at least the 2000 model). How many miles did you have on your truck when you changed it? I know you feel better now that you changed it but the factory fill would of been good for 30K miles, or maybe forever, depending how often/much you pull. Oh well it's only money

 

[RustyJC]

Re: Re: Royal Purple Rear Axle Lubricant

Originally posted by Big Toy Your 3500 with the Dana 80 comes from the factory with synthetic already in it, (been that way since at least the 2000 model).

Big Toy,



Here's the reason I changed it out (quoting from page 161 of the Owner's Manual - Synthetic Rear Axle Lubricant):



For all trailer towing or heavy duty applications it is strongly recommended that the factory fill rear axle lubricant be replaced with an SAE 75w-140 synthetic gear lubricant. Mopar Synthetic Gear Lubricant is of this type.



Quoting from page 206 - Rear Axle And 4x4 Front Driving Axle Fluid Level:



Dana Model 60F front axles contain "Thermally Stable" SAE 80w-90 Multipurpose Type GL-5 Gear Lubricant when delivered from the factory. Dana Models 80 and 70 rear axles contain SAE 90.



Rusty

 

[Pit Bull]

Re: Re: Re: Royal Purple Rear Axle Lubricant

Originally posted by RustyJC





Big Toy,



Here's the reason I changed it out (quoting from page 161 of the Owner's Manual - Synthetic Rear Axle Lubricant):



For all trailer towing or heavy duty applications it is strongly recommended that the factory fill rear axle lubricant be replaced with an SAE 75w-140 synthetic gear lubricant. Mopar Synthetic Gear Lubricant is of this type.



Quoting from page 206 - Rear Axle And 4x4 Front Driving Axle Fluid Level:



Dana Model 60F front axles contain "Thermally Stable" SAE 80w-90 Multipurpose Type GL-5 Gear Lubricant when delivered from the factory. Dana Models 80 and 70 rear axles contain SAE 90.



Rusty

Rusty

Looks like you are now ready for the heavy duty stuff. Mines a daily driver, sometimes I haul a couple of 40 lb bags of dog food. I'm sticking with the factory fill since I have a 100K mile diesel wrap warranty

 

[ageorge]

RustyJC, thanks for getting back with that #. The place I know of with the Royal Purple has it in 5 gallon pails, with just the # on the pail. Thanks again. Al