Took my ride to dealer a few days ago. They changed engine oil and trans fluid. The checked front and rear diffs. They came to me in waiting room to inform me they found 80/90 gear oil in both diffs. They stated that the correct fluid smells like grapes and that the fluid in mine was regular gear oil.

I told them it was last serviced at a dealer near my home (who just went belly up 2 months ago). They recommended that I change both diffs at a cost of $199.00 each!!! I stated that since a dealer did the work previously, DC should cover the cost to change out fluids. I am awaiting a response from the district manager.

My thoughts/questions:

Perhaps the dealer is just wanting to drum up business and my current oil is the correct oil????

If I did indeed have 80/90 gear oil, can this cause damage? Long term problems?

Thanks

PS: I am thinking of going to a Mag=Hytec rear diff and change fluid myself.

Also, will a Mag-Hytec fit on front diff on a stock height set up? I have stock ride with no lift. What if I later wanted to add a Bilstein steering stabilizer - would this still fit without mods or hitting?

Thoughts??? Tips on changing the diff covers?

Thanks!

 

i have never in all the diff fluids i have changed smelled grape like gear oil.
i run 75w in the front , and 140 out back, full synthetic.i change out every 100,000kms, and i run a mag diff cover out back, and just bought a front, i have a leveled truck right now, and looks to be no issues.

 

I think your dealer is smoking crack wanting $200 a piece to change diff fluid.

Do it yourself. Our axles, front and rear, call for 75w90 Synthetic GL5 rated gear oil. You can buy it at any auto parts store. I use Mobil 1 from VatoZone, but any GL5 rated gear oil in 75w90 is ok.

You simply get a big pan and put it under the pumpkin. Remove the cover and let the fluid drain. There should be a heavy rubber gasket that is reusable. Then replace the cover with the gasket in place and put your bolts back in. DO NOT OVERTIGHTEN!!!! Just snug them and call it good. Many guys have broken those bolts off by overtightening them. Your gasket won't let it leak. Then add in your fluid.

Remember 75w90 GL5 rated synthetic gear oil. Heavier is NOT better.

If you want to use Mag-Hytec covers they are fine. There has been some reported rubbing issues on the front diff MH cover......which is why I have a PML on the front. But I love my MH on the rear.

I know it's overkill, but I change my diff fluid every 20k when I do a list of other maintenance items.........and the fluid comes out looking brand new.

By the way.......I doubt your axles were hurt any by running the other fluid. I'd just order your new covers if you want.......go buy some fluid and change them as soon as practical.

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I think somebody has been sniffing something and it ain't diff fluid.


Get your truck out of there NOW before they change the plugs an wires, tell you they were the wrong brand, and charge you $500.


Man, the stories just get worse and worse every day.

 

I have the Kore Single damper and it just replaces the stock damper and center mount and doesnt get near the diff cover. I think if you got this one you would be fine. Works very well by the way. I know they offer a dual kit for the left and right side but I think this is over kill unless you plan on taking her to Baja .

 

Thanks!

I read in a post, that is later than this post, the Limited Slip additive is now recommended by DC. True? Most from what I jhave read states NO additive is needed, just the GL-5 syntehtic and that does it?

additive or no additive, that is the question???

 

Pretty sure the additive is for clutch type limited slips that we do not have in our 2500/3500's. I do not know why we would need it, my chrysler manual says not to add it.

 

No additive on our AAM axles. The GL5 Synthetic 75w90 is what and all that you need.


I believe the Dana axles on 2nd gens and prior require an additive.

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Down here in the south I don't bother running synthetics. I have run Mobil 1 75-90w with good results though. The AAM locking rear end puts a lot of metal particules in the oil so I like to change it often and don't use the benefit of synthetics. The front differential doesn't get the metal in the oil like the rear so I don't change it as often and it still has Mobil 1 in it.
Billy

 

The mobil 1 is synthetic. That's what I use too, with great results. But I don't notice alot of metallic particles.

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if you do change it yourself clean around the gasket and cover with wire brush, brakes parts cleaner, and maybe even shoot it with the air gun before you remove the cover to ensure you don't knock any grit/sand into the carrier...

 

You have to let it sit for a while to let the metal settle out. It can take a few days.
Billy

 

Actually,if they were using the same gear oil that GM recommends in their 11.5" AAM axle,it DOES smell like grapes.

Ask around on some of the Duramax forums. A lot of guys refer to the GM diff oil as "grape juice".

I always thought gear oil smells like B.O.

The first time I changed the gear oil in my 2500HD I was surprised. Sure as chit,the factory fill smelled like Grapes.

The Mobil 1 I poured back in wasn't quite as fruity though.

 

I change the differential oil myself. It's not a messy job and only cost what you pay for the oil. As far as Mag HighTech you may have to drop your track bar to install the front cover and if your spare tire is much over sized it may rub the rear Mag HighTech cover on short bed quad cabs. The rear one looks nice though.
If there was GL-5 in there you won't have any damage. It does't matter what kind.
Billy

 

I wish my truck came with the "grape stuff" in the diffs. The first time I serviced the diffs, the mopar gear oil that came out made my shop smell for days. Hopefully, the 75-90 Mobile One that is in there now will not smell as bad.