I have 11000 miles on my 07 and got a whine coming from somewhere. I want to change the diff oil, what weight should I use and how many qts? I want the best syn I can get. should I change my tranny fluid? I heard it was syn. from the factory.

 

Best diff fluid you can get is Amsoil Severe Gear. 75w-110 should be okey unless you tow a lot then I would go 75w-140. But since it gets pretty cold where you live I would stick with the 75w-110. JMO. No need to change the tranny fluid just yet. If my memory serves me correct my rear diff took 3.5 qts.

 

I changed to amsoil 75-140 at about 15,000 miles and mine was pretty crappy looking, mine took close to 4 quart`s.

 

question on servicing the diff-as I havent done it to mine-
How do you pull the old fluid out-just suck it out the filler or do you loosen the bolts & pull the cover?

 

Just wondering; is 11,000 miles a little early to change the fluids. I changed mine recently for the first time (100,000 mile) and everything still looked good. On our fleet of trucks (all 2500's) we change the tranny fluid around 50-75,000 miles pending on the driving history. I used lucas diff fluid with their conditioner and Schaefers for the Tranny fluid.

 

just pull the bolts, drop the old oil in a pan, clean out junk from the cover, put on a new gasket or high temp form a gasket and add the new stuff. thats how I have done it and havent had a leak yet.

 

You can take the cover completely off, the gasket is reusable, that way you can inspect the gears and wipe down the inside of the cover.

 

I would probably wait longer myself but that new whine worries me a little, it would be hard to hear if you didnt know the truck so I want to change the fluid before I try to take it to the dealer. I may have forgot to mention that I lost two NV5600 in my 06 w/less than 30,000 so I am a little head shy.

 

Wow, what happened to them? That is unheard of. (At least 2 of them in 30k)

 

The gasket is reusable and I would not add form a gasket to it and with as new as it is I would not hesitate to reuse the original gasket. It is important to use a torque wrench to tighten the bolts.

 

the first time was a main rear input bearing came apart and went through the tranny, the second was that the gears were to close or something and ground down and killed it. the dealer said they have never had that happen either. bad luck I tell you what.

 

75w90 fluid is what is recommended from Chrysler/AAM.

Any full synthetic GL-5 rated 75w90 fluid is fine. Heavier is not "better".
I am Not saying it hurts to run heavier though.

The factory fill has some sort of break-in formula and will probably look like watered down gray paint when you drain it. That stuff needs to come out asap...but beyond that....longer drain intervals are probably fine. I just go ahead and do mine every 20K with Mobil 1 75w90.

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I suspect factory re-mans have at least twice the failure rate of the originals. They only have to get you through the rest of the warranty period afterall.

(I learned this from the transmission experience I had in my last truck, a '97 Chebby 1/2 ton- 3 trannies in 90k.)