I was just in my local dealer picking up ATF+4 fluid and a filter for my 48RE. ($17.49 gal)
I asked the parts guy about the rearend fluid that Mopar sells. They sell a
special synthetic just for the DR2500/3500 with the 11.5" rearends.
It meets the GL-5 and some MS-XXXX spec and sells for $20.19 per quart. !!!
I need to see if my Mobil 1 Synthetic 75W-90 meets this MS spec. (I know it meet
the GL-5)

Anyway, over a $100 in fluid for only changing out 1 diff on my truck is WAY too much.
I have the PML rearend cover which add another 3/4 to 1 quart of extra fluid.

 

For my first differential service at roughly 2500 miles I used Amsoil Series2000 75w90 and was not pleased with it. For some reason it caused my rearend to chatter upon acceleration. This condition was even worse when towing my fiver. Therefore, at the 15,000 mile mark I drained the Amsoil and refilled the diff's with Valvoline SynPower 75w90. Now everything is smooth as silk and it's available at my local Napa.

 

I found the info from DC regarding AAM 11.5" rearend fluid
"Use Mopar GL5 Synthetic 75W-90 MS9763 fluid" "PN5102232AA
and PN5010320AA both meet this requirement:

The Mobil 1 Synthetic GL5 75W-90 does not mention meeting the
MS9763.

Anyone have an idea of what this MS9763 spec is ?
At $20 per quart for the Mopar fluid it would be nice not to have
to use it to meet warrenty issues

 

Mobil 1 synth was OK for mine, but it's a 99. On your 4X4, check the spec and see if 75w140 is not called for.

 

You third gen guys crack me up! My second gen is so loud, I couldn't hear the rearend chatter if I was sitting on it.

 

the new Amsoil severe duty gear lube works great, and meets all requirements.

 

pullin hard
Does it meet the MS9763 listed on the Mopar container ????

 

The newest Jug of Mobil 1 I bought caried the GL-5 rating so does the castro Synthetic. I personally have royal purple running in my rear now it also carries the GL-5 rating that is all my manual called for not sure of those other numbers you are quoting. The dealer probably trying to scare you into buying the 20.99 stuff you should be able to get a good synthetic lube for less than 10 bucks a quart.

 

I don't believe the lube needs to meet the Mopar spec number. Our AAM 11.5" is the same axle used on the GM trucks with the Duramax. The lube needs to be synthetic with a GL-5 rating. Either 75w-90 or 75w-140.

MikeyB

 

Don't fall for that crap the dealer sells. On my 2001 DMAX, they insisted on using the grape smelling stuff at $20 a quart.......No way! AMSOIL, MOBILE 1 or any of the other popular sys. work just fine if not better.

Think about it.....what makes this stuff so special at $20 a quart? NOTHING!

 

Well I know that it is not a Mil-Spec item as MS9763 is as follows:
"BOLT, MACHINE - DOUBLE HEXAGON EXTENDED WASHER HEAD, DRILLED, PD SHANK, TITANIUM AMS 4967, .4375-20 UNJF-3A (NO S/S DOCUMENT)"

Matt

 

I must be the red headed step child as I agree with you. I own a 3g but complain about the lack of noise all the time. If I had wanted something that rode like a car, sounded like a car, smelled like a car. and was as quite as a car, I would have bought a car. But instead, I have a pick up truck that has an identity crisis.

 

thanks everyone
I will use the Mobil 1 (GL-5) Synthetic 75W-90 I already purchased.

 

I didn't need to hear it because I could FEEL it .

 

i will look into the specs on the severe duty oil, but there are a number of specs the dealer will put on there bottle that an oil must meet, some of these spec are a lower graded spec,which the oil already meets. the GL-5 is an important one here, and is used by almost all truck and car manufactures. i just noitced that the severe duty didn't have the chatter like the reg75w90 gear lube, this goes for the series 2000 75w-90 gear lube. depending on the locking device you have in your truck , Amsoil has additives to reduce chatter, just like the stuff GM uses.i just converted a 98 Dodge ram,5 speed, with the Dana 60 front and a Dana 80 out back, single wheeled truck,with the 4500 tranny, to all Amsoil , and the guy told me that it starts easier, and has gotten about 75-100km better to a tank.this truck has about 300,000km on it (for you US people that would be somewhere about 180,000 miles)
just put the dual oil filters on it too.anyway, i will start a new thread if needed, but the gear lube works great.