Rear Axle Lube Change: What to Use

[Vaughn MacKenzie]

OK, with 6K on my Ram I want to get rid of the factory fill and all the breakin accumulation.



I liked Amsoil for my rear lube on the last truck and prefer to stick with Amsoil, but it seems their Series 2000 and regular gear lube already has "friction modifier" according to the website. AA says No to friction modifier. Does it really matter?



I'm not about to buy anything from the dealer. My bets are I'll be safe with Amsoil, Royal Purple, Redline, Mobil, etc. synthetic gear lube.



Vaughn

 

[timjones]

Vaughn,

AA uses re-labled Mobil1 synthetic, you can get it at auto zone.

 

[robobx]

Since there was no retailer nearby that sold redline, I order it from Summit racing. 7. 95 handling fee and NO SHIPPING charge gotta love that on heavy stuff

 

[Casey Balvert]

According to an email that I received from AA, Texaco makes a special formulation for the new axles.



"Casey,

Here is the scoop on the production lubricant. Texaco manufactures the lube for AAM's production axles. This is a unique blend of 75W-90 synthetic specifically mix for our application and is available though Mopar Parts at Dodge Dealers under part number 05102232AA. Safe travels.

John Nyquist

Director of Marketing"



I used the Mopar stuff for my first axle oil change.



Casey

 

[Southbound]

75W-90???

Hello-



I am glad this post started... ... ..... my friend and I just ordered some new HY-TEC covers and were wondering what lube to go with. We have used Amsoil in the past but was considering other alternatives this time around for our 03 models. This Texaco formula sounds interesting???? Whats the general feelings out there for 75W-90???? I know there was a post about this a while back but thought I would mention it again.



Southbound

 

[John_M]

robobx, Red Line makes two 75W90 gear oils: 75W90 Gear Oil which contains some friction modifiers and 75W90 NS Gear Oil which contains no friction modifiers. Both gear oils meet or exceed the required GL-5 standard. Which one did you order?



Vaughn, your question ... . "Does it matter?" is the one I can't find an answer to. American Axle indicates no friction modifier is needed with their Trac Rite GT differential. Will a friction modifier in the gear oil interfere with the proper operation of the differential? Is it AA's position that you can go ahead and use your 75W90, GL-5 gear oil if it contains a friction modifier; it's just that the friction modifier is not necessary for the proper operation of the differential?



I have a case of the Red Line 75W90, GL-5 gear oil with the friction modifier and I would like to use it if possible. I'll probably e-mail American Axle about this and call Red Line in California.



Best Wishes,



John_M

 

[Barry]

Wow, am I glad y'all started this. Questions I need answered.



1) Like or not like the Dana axles, do I need to change the fluid before the first tow?



2) I have always run a Mag Hy-tec and 75-140 Amsoil. Are we not suppose to run the 140 in the AAs?

 

[Greg Boardman-RIP]

I just installed Mobil 1 syn 75-90 about two weeks ago with a Mag hytec cover. No difference in performance. Goto autozone and get it. 6 quarts.

 

[_Hyde]

Barry, you took the words right out of my mouth. I've done the Mag and Amsoil Series 2k 75w-140 in the past as well. I'm wondering if I should go back with 75W-90 as specified and I'm also concerned about using lube that already has friction modifier in it. I wouldn't think that it would be a problem since much of the synthetic gear lube on the market already has some modifier in it.



Darren

 

[willyslover]

for those that have changed already and are wondering if you have screwed up your LS... . just go out and lay down a smoke show patch . . get out look at the pattern... two lines = ok to go

one line = too much modifier in your oil and your LS traction isn't working well.

if I was pulling frequently I would have the 75-140 [or in very hot climate areas]

no pulling [grocery getter] with occasional loads 75-90 would be just fine

 

[Barry]

Willy, thats kind of what I am thinking. Here in Texas when road temps get to 150 to 160 degrees, I think the 75-90 is a little on the light side. In my 01, I made 1 pull with an Alpenlite in the summer and in 500 miles, I fried the 90w. Luckily, I had my new MHT cover and 6 quarts of Amsoil to change it with. I do not want this to happen to my 03... ... ... ... ... .

 

[Greg Boardman-RIP]

Factory service manual recommends 75-90

 

[RMcCulloch]

Off-hand, I'd say that this is one of the differences between the American Axle and Dana differentials.



Danas need the heavier lube.

 

[smartineau]

Willyslover,



If I lay down two sets of tire marks I might be upset, I want four marks on the ground.



Vaughn,



I did as willyslover said but I chickened out and did it on a gravel road and did up four nice big gravel throwing marks on the road.



I also did the Mag-Hytec cover and filled it up with Royal Purple 75-90, I did this just prior to throwing the four strips of gravel.



I forget now how much I added but I believe that it was 8 qts.



steve

 

[willyslover]

Steve. . I stand corrected



couple things here guys... IF you just changed gear oil... make sure you do the figure eight's and then do your test... if not you will have a dry unit and it will work very well dry LOL. . grave road is way too easy on the test as gravel doesn't resist much [also plays hellll on the rear plastic fenders with chips]... wheels will spin both sides in gravel and still not show that the posi isn't working.



Barry only 6 qts ?... better check level and make sure to do fig 8 ths... need to get the oil into the axel tubes for proper level measurement

 

[Vaughn MacKenzie]

LOL @ smartineau



Gary I've already tested my LSD a time or two. This AAM axle sure is an improvement over the Dana version in terms of LSD performance.



Well I'm gonna get a few quarts of Mobil and call it good, since I can grab it locally.



Vaughn

 

[rbattelle]

My 15000 mile service is coming up soon, and like many others I don't intend to buy the $20/quart dealer snake oil. I was going to go with Mobil 1, but I read their label and it clearly states it is NOT full-synthetic. Instead, I think I'm going with Valvoline Synpower 75-90 full synthetic.



Are Amsoil, Redline, and Royal Purple API approved?

 

[draymorris]

I have had a small thread running called "metal in rear end" and there was another that I beleive many of you were on last week where many people were talking about the LSD not working - LOTS OF GOOD INFO ON THOSE THREADS AS WELL!



As for me, I replace my rear end fluid at 22k with Mopar and 40k with Amsoil Series 2000 75-90. Amsoil's tech dept told me that they recommended the 75-90 but the 140 was also acceptable.



As far as the heat and heavy pulling - synthetics are not supposed to break down - that is one of the reasons we use them! Right or Wrong? I thought that the engineering in the unit(gear meshing, bearing clearences, etc. ) determined the viscosity of the oil being used. Temperature, I thought was not as important when using synthetics.



I pull very heavy loads almost every weekend - most of my miles are pulling. Considering that I keep finding more metal in my rear end than I like to see, I would sure want to know if I am wrong in my lube knowledge.



Can one of you oil dealers chime in?

 

[DPKetchum]

neighbor just had his changed 03 4x4 six speed with 90K on the odometer for the FIRST time. He pulls a 3 horse gooseneck/horsesfor extra income. Insides of diffs looked new. Trans fliud was CLEAN. I'm a amsoli guy and will use it when time comes. Neighbor used MOPAR stuff.

 

[Joseph Donnelly]

I'm using LE 607 in a Mag Hytec cover.