What is the current viscosity recommendation for the AAM 11½" axle? The owner's manual specifies 75W90, but I've heard and read that the 75W140 is now being specified.

Which is correct? My current plans are to use Redline 75W90. Any suggestions on a better lube to use?

 

Curious also.I just refilled with Amsoil Severe gear 80w90

 

i've got 75w90 synthetic in mine now... if you are towing heavy, or in hot weather nearly all the time, the 75w140 should be fine too...

 

I used Mobil 1 75W90 in the front and 75W140 in the rear.

http://dodgeram.info/tsb/2004/03-001-04A.htm

TSB 03-001-04 REV. A

(DR) RAM TRUCK 2500 - 3500
AXLE FLUID LEVEL
(measured from the bottom of the fill hole) FLUID CAPACITY
10.5 Rear Axle 25 mm (1 in.) ± 6 mm (1/4 in.) 2.5L (85 oz.) - SAE 75W-140 Synthetic
11.5 Rear Axle 6 mm (1/4 in.) ± 6 mm (1/4 in.) 3.6 L (122 oz.) - SAE 75W-140 Synthetic
9 1/4 Front Axle 6 mm (1/4 in.) ± 6 mm (1/4 in.) 2.2 L (76 oz.) - SAE 75W-90 Non Synthetic

 

So the current viscosity recommendation for all 11½" is offically 75w-140?

 

Most people on here are still useing 75/90 and i think that the dealer changes are still 75/90, but then they are not aware of most tsb's seems that if you are really working the truck then the 75/140 is the way to go. the part that i don't get is why they recomend non synthetic in the front dif?, i think most people are useing synthetic in there anyway with no adverse affects.


rob

 

I read one weight and then another.I work my truck usually.I used the amsoil 80w90 in both front and rear.I called Amsoil tech line before I bought.They stated eaither was ok protection.Maybe if I lived in the high temp areas 24/7 I would have used the 140 weight but I don't,so.

 

I'm running Royal Purple 75w-140. Wanted the added protection in the hot Texas climate.

MikeyB

 

The truck makes less driveline rumble with the 75W140, more noticeable in top gear at low speeds. The Mobil 1 makes for a LOT cleaner oil than the dealer stuff at change.

 

Will the Redline or Royal Purple 75W90 cause damage or more wear than a 75W140? I tow a 5500 lb boat occasionally.

 

Has anyone used standard oil in these rear ends?

I am not a huge fan of synthetic oils and there prices, stuff looks weird and costs a ton of money and never really see a benifit to it.

Jason

 

The specs and warranty require synthetic, so why take a chance?

As far as what weight, IMO, if you don't tow heavy, use the 75/90. A heavier weight oil has more drag, so will cost you fuel economy. That's the reason the new cars call for super light weight 5/30 or even 0/30. For fuel mileage to help with CAFE requirements.

 

I put Redline 75w90 in mine at 15k. At 30k I checked it and it was VERY clean with a small mud ring around the magnet. At 45k I plan to check it again and maybe change if dirty. I drag one of my trailers around a couple times every week, the heavyest being around 8000 pounds and the heat here in Florida dosen't help either. IMO Redline 75w90 or 75w140 is about the best you can do.

 

2 weeks ago I sent this to DC:
"I have a question about axle differential fluid for the MY2004 Dodge Ram 3500 4X4. My owners manual states that the differential fluid should be 75W-90 synthetic, but I just saw TSB 03-001-04 REV.A, dated May 11 2004, which states that the fluid should be 75W-140 sythetic. What is the correct fluid viscosity?"

They responded:
"Thank you for your recent email to DaimlerChrysler Motors regarding your maintenance requirements. As in your owners manual, as well as on page 2 of TSB 03-001-04, the Ram 3500 is required to have 3.6L of SAE 75w-90 for your 11.5 rear axel and 2.2L of SAE75W-90 for your 9.25 front axel."

So who knows...

 

Yeah, I changed mine too. First change was @ 5K with Royal Purple 75 90. Honestly, when I opened it back up @ 18.6k, the oil smelled and looked like I put in an hour ago on both diffs. Clean as a whistle. This time I used Mobil 1 75 90. I think if you tow moderately, the 15K change is an overkill. My next change I will replace the cover with a PML or Mag-Tech.