Rear differential fluid
 

What kind of rear diff. fluid should i be running in my 04 2500, and should i run the same in the fron diff? Also what kind of tranny fluid should i run, its a manual 6spd, and how often should i change that?

Front: 75W-90 tad under 3 qts
Rear: 75W-140 tad under 4 qts
Transmission: ATF+4 6 qts

Service every 40,000. Less if you do a lot of towing

NV 5600 doesn't take ATF...

https://www.dieselbombers.com/5-9-li...intenance.html

Ram NV5600 specs

Also your AAM 11.5 (rear axle) comes with 75w-90 from the factory but a 75w140 will work too.

Thanks for all your help guys, also i noticed my rear diff. fluid is a milky brown color, what the hell does that mean?:argh:

How many miles? It's likely from water contamination.

Make sure to get limited split additive if it doesn't already have it!

Aam's don't require a ls additive like the fords do.

Calls for 75/90 in both, but some run thicker in the rear. 75/100 is a good middle of the road but I don't know who else makes it but amsoil.
This also has ls additive in it so no extra needed. Good for 100k or for 50k for most of us(towing).
Highly recommend synthetic, brand is up to you.

i think i might have around 20-30k since i last changed it.

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so you recommend 75/140?

I would have to disagree with you on that, I tried that just to see if I could save a few bucks and it started chirping when making hard corners. As soon as I added limited slip oil it went away. But that is only if you have a limited slip rear end though too.

Never needed to throw the additive in the AAM in my 04.5, IIRC it said in the owner's and service manuals additive not needed.

Who knows, I would just empty it, fill it with fluid...drive around a bit and if it needs it then put it in. But the factory says you don't need it...that being said the factory thought 10 micron fuel filters on a 26k+ psi fuel system was a good idea. :argh:

do you think 75/140 is to thick?

It will cause no harm. It's just more than what's needed. If u put a good 75/90 in you'll have no problems. I use 110. Just didn't want to go to the 140 in case it dropped my
Mileage at all. Any will work.

Your axle will be fine with a 75w140, I ran that in my dodge when I had it. Didn't notice any drop in mpg. I am not amsoil's biggest fan but I will say their gear oil is second to none IMHO. between them and redline you can't go wrong.

do you think a thicker gear oil will cuase more harm then good? Should i go 110 not 140, or does it really matter?

Didn't do any harm when I ran it in mine.

im going with 75/90 in mine (amsoil) but i use it for mostly a daily driver and when i haul its not very often, now if you haul alot but not very heavy loads i would go with 75/110 and if you haul heavy loads alot i would go with 75/140

You can run them all no problem. Flip a coin:tu:
I went middle of the road with the 110.

Its needed with some fluids...if it chatters, add LSD additive.

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I ran a single fill of Royal Purple 85w140 for well over 100k...it looked like new when I drained it and had zero metal on the magnets.

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Milky brown is likely water contamination as noted...it can also be aeration.

From what I've always heard, thicker gear oil within specs will provide you with better protection if you are towing heavy loads or offroading. Otherwise it will negatively impact your fuel economy. If you aren't towing or wheeling, I'd stick with the 75w-90 synthetic w/ limited slip additive.

Running royal purple 75-90! It's amazing how hot they get i put a temp sensor in it and 280 is normal!

I ran RP 85w140, and never saw anything close to that? I was measuring at the case and cover with an IR gun, max I ever saw was around 150. I did have an aluminum covwer though.