Rear Differential Lube Change Interval

[HBarlow]

I had forgotten until I read the posts here that mentioned the importance of the first differential lube change.

Actually mine was changed at 350 miles. It is 300 miles from the Chrysler-Dodge dealer in Gainesville, TX where I buy my Dodges back to my home in Lubbock. My current truck and the one before it were driven home from the dealer before the fluid was drained, the Mag-Hytec cover installed, and seven fresh quarts of synthetic lube poured in.

The 300 miles may have provided the initial break-in miles and flushed out any manufacturerning process debris so I found no particles at 48,000 miles which in truth was actually the second change.

 

[brods]

Harvey, you should go back an edit your first post to mention an early drain. I did my first change at about 17K and realized it would have been better to have done it much earlier. The results since then have matched your experience.

IIRC they recommend 500 miles to break in the rear before towing, maybe that would be the best time to do the first change?

Also remember manufacturing is not always perfect. I was involved in meetings about filtration for a ring & pinion parts washer. It was because of warranty issues on a sedan that was having premature differential bearing failure. So an early change is a good idea!

 

[HBarlow]

Okay, good point. I'll go back and add an edit.

 

[steved]

I look at it this way:



This differential, short being produced by AAM, is not all that different from the previous generation's Dana-produced axles... same types of bearings, races, seals, and same type gears. Just because it has a different name on the case, doesn't mean its not almost 60 year old technology. AAM is an old company... with equal experience as Dana. How many of us even bothered to change the fluid in our Dana? I personally put 200k on one Dana, and only changed the fluid because the cover started leaking... it has over 290k currently and is still going strong.



It is common to find metal in the first change on any differential... things get deburred with time and castings inherently have material work loose after some heat/cool cycles. I changed my differentials at 50k (first time), and the magnet had fuzz on it... the next time, around 25k later, the magnet was clean. Now at 190k, the magnet has not had anything on it since that initial change...



One thing we tend to not think about is gear oil, it is pretty tough stuff in reality. Its definitely not as fragile as automatic trans fluid. Add to the fact that most of us use synthetics, pretty tough stuff. Not to mention that many of the Dana offerings never came with synthetic oil... and neither did a lot of older AAM axles...



I believe an aluminum cover does help quite a bit since it can only help reduce operating temperatures, plus most aftermarket covers add volume (further promoting heat transfer and providing more oil to shear).



I was planning on 100k changes, but a leaking pinion has forced me to complete at least partial changes due to oil lost during seal replacements.



I would personally like to know where the 15k change specification came from, how it was developed/agreed upon by DCX. What made them consider changing the differential oil as often as the engine oil?? Was it testing? Or was it speculation/assumption? Was it based on unit failures? For example, the Corp 12-bolt (Eaton) used in the 1500 is using 75w140 and, from what I remember, has no change interval... yet you have towing capacities nearing 10k pounds on a semi-floater...



Just some thoughts...

 

[HBarlow]

I agree. I wonder if the service interval is established to enhance profits for Dodge dealer service departments.

 

[Wingate]

Just out of curiousity, but does anybody have a late model GM pickup that they can see what the owners manual reccomends for fluid change interval????. . Its my understanding that the GM and Dodge share the same differential.

 

[steved]

I asked the GM owners once on another general diesel forum, I cannot remember if anyone actually responded. That was right after I bought my 04. 5.



The newer rear diff and the center sections are the same from dodge to gm... the older rear diffs were only different between the castings (the center chunks are the same)... several dodge owners have used gov-loc center chunks to replace the trac-rite. The gm and dodge 9. 25 are the same... they use the same ARB locker.

 

[S.Morris]

Just did a diff service on my 04 Drw. Had red line installed at approx. 80K according to records. . not sure if this was first change.

This time installed amsoil (because of pia trying to get red line

175K miles... so 100K on oil. It was in very good shape with very little on magnet.

Gear wear pattern and backlash was as new. This truck has never pulled heavy.

I will maintain 100k intervals with quality synthetic.

Steve

 

[Jim W]

I know this truck is not a current one, but I owned a 2001, 2500HD 6L Auto, SB Chevy. Sold the truck to my one son when I bought my Dodge in Nov of 2007.

I had the truck serviced by the local dealer at the 30K and 60K mile marks as Chevy suggested. If my memory serves me correctly the diff fluid was changed both times. I looked up the bill and this seems correct to me since they charged me $426 in 03 and $760 in 07.

In 03, I had the cooling system fluid, diff oil front rear, engine oil replaced and chassis greased. In 07, I had all of the above plus the trans fluid, the spark plugs and spark plug wires replaced.

That's the best that I can remember and I do remember having the diff fluid being changed twice.

I was planning on keeping this truck for a very long time but pulling a 5er it would not work with a gas engine.

 

[steved]

I just asked on a Duramax forum. Seems the required service is "check fluid level". They have no specified change interval for the rear differential.



So that really confuses the issue... Dodge specifies a 15k change interval and GM has no change interval for the same differential.



You wouldn't think the 15k is a misprint that was carried through would you? I could see 150k service intervals. Or maybe someone replaced "check" with "change"... I can really see doing a fluid level check every 15k.



Do you think something like that could have made it through multiple reviews??

 

[macdaddy]

I agree with all of you.....



Mine was done at 15K reinstalled stock covers oil was nasty.



30k Oil was pristine,installed PML on front(Mag High Tech wasnt available yet) and Mag on rear.



Just did it again at 75K. My God what a waste of money that was. It was like the day I poured it in. And at $200. 00 for the rear alone what a waste



Mac

 

[EArp]

I just did the front and rear diffs today with 49k on the clock. I used the Mobil 1 synthetic 75-90. The old fluid looked good, but I expected that since I don't tow anything. There was just a little "mud" on the rear plug but nothing too serious. I went ahead and serviced the transfer case while I was at it.

 

[NavyDood]

You wouldn't think the 15k is a misprint that was carried through would you? I could see 150k service intervals. Or maybe someone replaced "check" with "change"... I can really see doing a fluid level check every 15k.

I have the FSM's from 03 to 06. They all say the same thing.

 

[brods]

I just asked on a Duramax forum. Seems the required service is "check fluid level". They have no specified change interval for the rear differential.



So that really confuses the issue... Dodge specifies a 15k change interval and GM has no change interval for the same differential.



You wouldn't think the 15k is a misprint that was carried through would you? I could see 150k service intervals. Or maybe someone replaced "check" with "change"... I can really see doing a fluid level check every 15k.



Do you think something like that could have made it through multiple reviews??

There is a current GM recommendation to change the oil at 5,000 miles if the axle is equipped with the G80 diff. The reason was to remove any break in debris. There was no recommended change interval after that.

 

[rbattelle]

We've been perplexed by the 15k spec since these trucks first came out. I think most people ignore it.

I was following it until 60k, for warranty purposes. Now I'm thinking of going 30k between changes (which is still probably overkill).

It would be great to ask a Dodge and/or AAM engineer what the source of the 15k was. I can't help but wonder if it has something to do with the 75w-90 specification whether you're towing or not.

Ryan

 

[Gary - K7GLD]

I may have missed it in the previous posts - and I realize this is a 3rd generation thread, and the later differentials are different in construction than that of the older, clutch-type limited slip Dana units. BUT since some of the owners of the older generation trucks also read here, it should be noted that the earlier differentials sometimes can add significant shed limited-slip clutch material into the lube, creating a contamination source all it's own.



The differential lube in my '02 has been changed several times in 65K miles - and while the lube in general was nice and clear, and very little "mud" was on the magnet, there WERE observable random small bits of non-ferrous material suspended in the lube. Probably not as abrasive as metallic wear particles - but something to be aware of in the older generation trucks when considering lube change intervals...

 

[RSchaecher]

Where do you purchase Mag-Hytec covers and do you install them on the rear and front? Its time to change the rear and front fluids on my 04, stopped at dealer today and they say three quarts each front and rear with one gear conditioner for the front at $12 and one limited slip conditioner for rear at $12, does anyone use these if you are using synthetics?

 

[steved]

Where do you purchase Mag-Hytec covers and do you install them on the rear and front? Its time to change the rear and front fluids on my 04, stopped at dealer today and they say three quarts each front and rear with one gear conditioner for the front at $12 and one limited slip conditioner for rear at $12, does anyone use these if you are using synthetics?

Geno's Garage sells the mag-hytec covers...



As for the differential... I believe its three quarts for the front and four quarts for the rear (with stock covers). You do NOT need anything besides a quality synthetic oil, unless you experience LSD chatter (some 3rd gens do for whatever reason) and only then might you need to add a small quantity of LSD modifier to the rear axle.



If you can turn wrenches, changing the fluid in the 3rd gen is easy because of the reusable gaskets.

 

[Wingate]

Bought mine at genos also... . The front cover is slightly more time consuming to install due to front end components obstructing the top bolts. The covers come with an allen wrench, but I found that using a ball-end t-handle wrench worked much better. The rear capacity with the Mag-Hytec cover increases from the stock 4 quarts to 8 quarts... I did some temperature testing with the stock cover vs. MagHyec and saw a significant temperature drop while towing.

 

[LAllen]

How did you get the cover off ?