ok - first thing I see is that the TSB on Geno's is a "OLD" release of the update (dated Jan. 04)...... I pulled eveything off of DODGE Tech authority a few weeks ago and the TSB does say what te manual states for oil... 75 - 90 wt. for the 2500's.. (tsb dated May 2004)....

As for the fill - if you look at the 10.50 axle.. it is really the only one in the 2500/3500 tsb graph where the fluid level is lower... approx 1 inch, or 25 mm.. when filled... it will not reach the drain hole...

The other two... 11.5 and 9..25 will be 6mm, or 1/4 inch below the drain hole... if you add the +/- 1/4 inch... it CAN come to the drain hole... this should not be an issue...

**put another way.. the 10.50 rear axle is the ONLY one that may have issues if you just open and pour it in!! the CORRECT level is 25 mm, or 1 inch below... if you add the +/- (1/4 inch), then it will be at 3/4 inch below drain hole...

** just noting what is stated on the TSB... nothing more.. if asked all I will say is it is a Republican thing and I do not recall!!

 

I have the 11.5" so what you are saying is that I am OK?

 

Pointing Labs, you are ok that you have the 11.5. But ok for what? Thats the question.

If your 11.5 is filled to the hole, you're golden. Keep on truckin'.

 

The TSB gives us the necessary capital to fill the 11.5 to the hole!

 

that is correct!

 

Wow! to fill to the hole or not. I can not see how 1/4 of an inch makes that much difference. As far as foaming the lube, most of the common lube's have anti-foaming agents in them to keep them fluid. I have also never seen one leak because of to much lube. It probably is possible to leak at the axle seals at the wheels and have had that happen on several truck I owned. Probably due more to wear rather than lube.

 

I just filled mine with the 122 oz recommended in the TSB for 11.5 and it was exactly at the bottom of the hole. I wonder why 75W/140 syn costs twice as much as 75W/90 syn?

 

Newer AAM axles have a fill level mark on the coverpan.

Mine had the fill mark, but it's more like 3/4" from the hole, not at the hole.

What a PITA. Not that it's in liters, not that it needs special fluid, but that they keep flipping it around. Making it confusing as can be. First it was 75W90 for the HD trucks and 75W140 for the smaller stuff. And different levels for each. Now it's 75W140 for the HD's too? And the fill levels just keep moving around.

Overfilling will probably reduce your axle efficiency (fuel economy), but should not damage the system.

At least I've got that going for me. Can just do it the ol' way and leave it be. Oh, but wait the dodge TSB disagrees with that too. GRRRR....

 

Can I add another twist to this pretzel?

I have the Mag-Hytec rear differential cover which has a dipstick for checking oil level. Does anyone care to guess if the full mark on the dipstick is accurate.

I just changed my diff oil with 75W90 prior to reading this thread about the change to 75W140. Will I be good to just leave it in for another 25,000 miles? The stuff is too expensive to just drain out now.

Thanks.

 

Maybe Mag-Hytec will have a TSB on dipstick length!

 

Gunship,

First you have to decide which level on the stock cover to use...I'm using the line on the cover for now. Then you will have to do some measuring to transfer your level to the Mag-Hytech. Last measure your dipstick and mark it.

I bet 95% of trucks are using 75W-90 unless the factory fill is 75W-140. DC hasn't told us about the TSB, only the people on DTR and TDR are aware. Before I tow again, I will probably switch to 75w-140...unless they change their minds again.

A note to DC: WHAT IS SO **** HARD ABOUT THIS???

 

Huh?

 

Big Jimbo -

REF. 75 - 90 wt. vrs 140 wt. oil

too be posted at a later time...

 

OK I'm getting ready to change the fluid and I want to get it right. I now have to use 75w-140 in both the front and rear instead of 75w-90. Now what brand? I saw Valvoline in Napa the otherday and was going to get that. It should be good as long as it meets the requirements right?? These oil questions and posts get my mind twisted around. Thanks

 

I wonder if GM has changed their spec for the Dmax trucks as they have the same Diffs?
I just changed my diffs again (Mobil 1 75-90 synthetic) I have a Grande Cherokee that calls for 75-140 and I know DC are very proud of that oil as is reflected in their price. I just bought a case of the Mobile1 75-90 and I will use it up in the Front diff ( because of the cold weather that we can get up here,I will continue to use synthetic in the Front diff.) Who else makes a 75-140 synthetic besides DC for my next change?
Jim O