Confused about rear diff

[CrimeFighter]

Ok, I have read alot of posts here and read freq asked questions and still cant get a straight answer.

So With our front and rear diffs we dont need the extra additive I understand that. But I have read here somewhere here it depends on the Axles you have in your truck. I have an 03 2500 quad w/short box do I have the axles that need this or dont I ?

What I want to do is use Royal Purple 75-90 synthetic but they say it has the additive already in there. Will this work without giving me the clunking I keep hearing about?

If Royal Purple wont work what do I get besides screwed at the dealer for thier stuff?

 

[LightmanE300]

Crimefighter, you do not need any friction modifier additives on your 03, no matter which axle it has (10. 5 or 11. 5). Your RP will work just fine. What a lot of people don't realize is that all the gear oils contain an amount of friction modifier, it's just that some axles require extra. The fact your RP has some is normal. If you aren't comfortable using it you can get Mobil 1 75w90 or Amsoil. I've had amsoil series 2000 75w90 in my front and rear diffs for 15k now, no issues. Hope this helps!

 

[mberry]

I put Royal Purple in mine and do not have any clunking issues or anything with them so far.

 

[CrimeFighter]

Thanks guys, this is why I subscribe!!

 

[SRadke]

Call me crazy but I drained mine at 15k (thought I'd get a jump on the maintenance) and found a normal open diff with steel gears and bearings. Same thing that's been used in trucks for over 40 years. I filled it up with good ol' GL-5 dino and it's still going strong at 32k. If you don't have a LSD don't worry about it.



-Scott

 

[SMorton]

The rear axles in the 03 and up are now american axle, no longer Dana, and they use a torsen differential, either open or anti spin, and do not require the use of any extra additives. This is because they don't use clutches like the old Dana units. It is a helical gear/load sensing unit, good for the lifetime of the truck, and is filled at the factory with synthetic lube. If you do a web search for Torsen T-2 or just Torsen you can find more info, or you can also go to the american axle site. Very durable, this type of anti spin unit has been used for years by Hummer, Audi and many other auto makers. The old additive was needed to keep the clutches from chattering. A slight amount of shuddering under load is normal, it takes some getting used to. I did a lot of research when I got mine, I thought my special order truck came through without the anti spin axle, and thanks to a very patient and knowledgable service manager, who gave me the web sites of the axle maker and differential maker, I learned how this baby works.



04. 5 2500 Q/C SWB 4X4 48RE 4:10 ANTI SPIN rhino liner, mopar mud flaps, wheel well liners, and all the other goodies I ordered Well worth the long wait!!

 

[WoodChuck]

Call me crazy but I drained mine at 15k (thought I'd get a jump on the maintenance) and found a normal open diff with steel gears and bearings. Same thing that's been used in trucks for over 40 years. I filled it up with good ol' GL-5 dino and it's still going strong at 32k. If you don't have a LSD don't worry about it.



-Scott

You might have something to worry about.

The factory spec calls for synthetic oil in all the diffs now. LS or open. Reason being that our motors keep making more power and we like to work the **** out of 'em towing what ever we want. Synthetics keep lubricating at extreme temperatures where Dino oils cant.



The LS in the new trucks is a gear type (Torsen-Gleason perhaps) and as such needs no friction modifiers. The modifiers are only needed on LS axles that use clutches like the Dana's power lock and GM's posi-traction.

 

[WoodChuck]

Torsen Gleason LS

This differential is also the same a Tru Track.



http://www.sonic.net/garyg/zonc/TechnicalInformation/TorsenDifferential.html



One interesting thing about this LS is that when you have both tires in the air and spin one side the other side spins the opposite direction which is not typical for a LS. Normally both tires will turn the same direction if you have a LS.

 

[Dean Upson]

I spoke with a tech at American Axle and he told me to be sure to use the FULL synthetic oil, not part synthetic or dino. He was quite adament about that. He did not say anything much about the friction modifiers except that the AA does not need them.



Dean