Diffy service

[DFranks]

Hey, just a question for those that have changed their own front and rear diffs. Any particular brand you would suggest or refer me to use on my 06 2500?. I would like to use a full synthetic if possible.



BTW what is the suggested weight of the oil for the diffs?



Thanks in advance for you info/advice

 

[jelag]

I've gone back to the dealer if I couldn't find an exact oil from a wholesale supplier... . The last problem you want under warranty is for them to open it up and find something other than the correct oil and the correct color... .....

Out of warranty I'd go to a full synthetic with no problem... .

 

[Dieselnerd]

I use Mobil 1, 75W-90, it's one of many "correct" oils available that you can use. Synthetic is called for and it comes with synthetic from the factory.

 

[rbattelle]

I use Valvoline Synpower 75w-90. GL-5 full synthetic.

I'm getting ready to try some Kendall Elite 75w-90, which apparently is identical to the Valvoline (made in the same factory, poured from the same machine, different bottles).

Ryan

 

[Bertram65]

Mobil 1 75/90 every 15k

 

[roperteacher]

Usually use Mobile 1 75/90 But switched to AMSOIL Severe Gear 75/90. . PML Cover as well, Dealer endorsed. Some dealers even Install AMSOIL fluids and it will not void the warranty...

 

[CDonaldson]

I'm using Amsoil 75w-140, have MagHytec cover. I live in a hot climate and do a lot of heavy towing. The oil meets specs, dealers everywhere use it, I see no problem. They cannot give you a warranty problem over another brand of oil as long as it meets specs.



You might want to consider moving up to 75w-110 or 75w140 as Dodge has changed its recommendation from the 75w90. Plus Dodge is also recommending using the additive with the limited slips now. The Amsoil Gear Lube salready have the additive.



I was told 1 year ago when I purchased my truck that when it came to changing the diff oils to go up to 75w140. My dealership went out of their way to make sure I knew to go to the higher visconsity when I changed out my diffs. My last visit they again mentioned it as I am getting close to the 15K recommended changeout. What they don't know is that I changed it already at 5K when I installed the MagHytec cover.



There is a discussion over on http://www.carsondodge.com/ regarding the diff oils and the recommended changes. Good info from TDR's own John Holmes.



CD

 

[liberty]

I used Chevron 75-90 synthetic in mine and I added the mopar anti-slip lubricant to it, even though I'm not supposed to need it.

I ran for about 2 weeks without it and I was getting rear end shudder.

I added 1 bottle of the anti-slip lube and it works perfect.

Dallas

 

[Cattletrkr]

I'll echo what CDonaldson said. My dealer will dump in 75W-140 if they know the customer is doing heavy hauling. My last rear change I went with Amsoil Severe Gear 75w-140. That oil now has 43K on it. I checked it the other day and the oil on the Mag dipstick looked just as clean as new. The magnet had filings on as always, but the oil was the cleanest I've ever seen. I still run 75W-90 in the front diff. I figure that one's not running anyhweres near as hot as the rear so why bother.



I've sampled Amsoil 75w-90 out of the rear with 35K or so on it and the analysis comes back just fine. I'll probably run the 140 to 75K or so and then dump it regardless of what it looks like.



I've never had any shudder or chatter and I've never added LS additive to the '04. 5.

 

[Bertram65]

I'm using Amsoil 75w-140, have MagHytec cover. I live in a hot climate and do a lot of heavy towing. The oil meets specs, dealers everywhere use it, I see no problem. They cannot give you a warranty problem over another brand of oil as long as it meets specs.



You might want to consider moving up to 75w-110 or 75w140 as Dodge has changed its recommendation from the 75w90. Plus Dodge is also recommending using the additive with the limited slips now. The Amsoil Gear Lube salready have the additive.



I was told 1 year ago when I purchased my truck that when it came to changing the diff oils to go up to 75w140. My dealership went out of their way to make sure I knew to go to the higher visconsity when I changed out my diffs. My last visit they again mentioned it as I am getting close to the 15K recommended changeout. What they don't know is that I changed it already at 5K when I installed the MagHytec cover.



There is a discussion over on http://www.carsondodge.com/ regarding the diff oils and the recommended changes. Good info from TDR's own John Holmes.



CD

Is the weight change reconmendation and additive documented anywhere? like in a TSB?

 

[CDonaldson]

Hey Bertram65.



I believe that John talks about a service memo or service bulletin, there is probably no TSB - that would make DC have to cover the change if you did not have 15K on your truck and were not at the service interval. More than likely they suggest it be upped at the service interval after "break in". I just got a new Diesel 101 package from John, I'll take a look and see if it contains anything regarding the fluids. John is an Amsoil user himself.



I think the new Amsoil 75w110 would be a good change out for the front diff and the 75w140 for the rear diff. Just my thought on the subject when doing a 4x4. I'm also changing my G56 to the Amsoil transmission Fluid. I really like the Amsoil products, they have lived up to their claims and have good service life.



CD

 

[DPKetchum]

Been HEARING about the 75w140 and using additive for a long time but have seen nothing in print from anybody. I am using Amsoil Severe Gear 75w90 and after towing a few hours develop a SEVERE shudder. I have since added liminted slip modifier which took care of the shudder on left turns but have not towed heavy any distance to see if the severe shudder hot is gone.

 

[JRMora]

I use Amsoil 75W-90 Severe Gear. I have never had a shudder issue even when towing near 23,000# combined. The only issue is a slight whine when the temps are down below zero, but once the rear end warms up, it goes away. I had the same issue with Mopar 75W-90, too.



I change every 15,000 miles, and changed it a few thousand after our 2000 mile 110° summer trip to Vegas and LA. Gear faces look great. I am at 67,000 miles.



Juan

 

[TowPro]

I think I see a problem here. The original post is for an 06 which has an AA axle. Some of the replies are from owners of the Dana Axles. I know Dana called for 75w140 for towing, but I thought AA only called for 75w90

 

[Nelssen]

I use this 75-140. I put it in front and rear. The dealer was way too much
$$$$.
http://www.schaefferoil.com/gear_oils/167_gear_oil.html

AA axles.
Your dealer will upgrade to heavier factory lube in the diffs if you tow heavy.
They will charge you more too. They recommended the heavier lube for running in the hot deserts here in AZ. as well.

 

[rbattelle]

Those of you using the thicker oil might be interested in this.



Ryan

 

[Bertram65]

Without something in writting from DC or AAM I would not switch from what is specified in the manual.

 

[CDonaldson]

rbattle.



Thanks for the link, very interesting reading regarding manual trannys and how their gears differ from those used in manual diffs using gear oils. I think that one has to take into consideration the visconsity in the overall picture. The 'low surface' and 'high surface' are what the ranges in these oils have reference to in their 75w90, 75w110, and 75w140. Note that all are the same in the low surface and that the variance is only in the high surface. I would never use anything other than the 75w90 diff fluid when I lived in PA as the ambient operating temp/driving application ranges were well within the range of that gear lube. Here in the desert sw the ambient operating temp ranges/driving application ranges change due to the hot road temps. A 75w90 gear oil is at the top of its performance range in our operational/driving environment.



No different than ranges specified for the engine oil to be right for our operational conditions, gear oils also have operational ranges. So one's choice of a diff fluid should have similar operational/driving application thought behind its use, and we should or need to understand thee things when making gear oil choices.



As far as something coming out of DC or AAM being the bible to what choices I will or will not make regarding lubrication for my diffs, let me just say that using a mfr rec fluid vrs something equivalent or better is by no way or means not in keeping with good maintenance practices. Choosing or using something that has taken into consideration the operating range of the fluid and the driving/use is one step up in better maintenance practices. Plus, when you get out there over the normal 3-36 drivetrain warranty or even the timeframe of an extended warranty all repairs are out of your pocket. More often than not diffs fail after 100K timeframes. I have always selected my fluids based on the ranges of my use. I have never had any diff failures in any of my trucks, and most all of my trucks have mileage that well exceed the normal lifetime of the diff and most have gone double the mileage and then some. This AAM diff is new to me and all of us, it already has some early wear issues and breakdowns. Since a reputable dealership and a reputable spokesperson have taken the time to go out on a limb and discuss moving up to a better operational range fluid, I think I will take heed, apply what I know, and follow suit.



I do plan to contact AAM and ask about this, hopefully they will respond to me in writing. I really do not care what DC's position might/or might not be as they have theirs more rooted in not taking care of problems, just band aids and buck passing to get out of most warranty issues.



CD

 

[Bertram65]

Manufactures spend a lot of money figuring out what are the correct lubricants for their products, be it DC, AAM or Cummins. Unless the manufacturer comes out with a recommended change in writing how can anyone think they know better than them?

 

[Cattletrkr]

Manufactures spend a lot of money figuring out what are the correct lubricants for their products, be it DC, AAM or Cummins. Unless the manufacturer comes out with a recommended change in writing how can anyone think they know better than them?

That is exactly correct... for a stock truck running within its design parameters. Some of us don't fit that description.