Rearend Fluid

[NHHEMI]

Originally Posted By: Riz
Going to change diff fluid in my o9 ram. I know I need to use 75-140 syn. There are soo many choises out there don't know what to use.


I am a Dodge guy at heart and have had a lot of Ram's over the years( I would still have my 08 Ram w/ HEMI I just sold if not for becoming ill and the resulting financial issues ). The last 3 called for 75W-140 in the rear diff. I have always used Royal Purple MaxGear in my trucks. I used the 75W-140 as required in the last 3 and it worked very well in those applications.

If you have the 3.92's w/ LSD the RP gear oil has the FM already in it and you shouldn't need to add more. Sometimes an LSD gets picky and will require a little extra be added but best bet is to try it without any extra 1st. That actually applies to any brand with FM in it already. If you do not have the LSD do not worry as the FM won't hurt anything.

I recommend RP MaxGear 75W-140. It meets all of your warranty requirements and is a premium product.

Question??? Is this a 2WD Ram? If it is 4WD don't forget to do the front diff as well. Always do them together as maintenance unless there is a specific reason such as a failure that causes you to do a change. Front is 75W-90 and again I recommend RP.

 

[-SyN-]

If you ever own a truck with a rearend temp gauge and you monitor that gauge with regular dino gear oil...Then switch to a high end gear oil like Amsoil SVG-SVO-SVT or Redline...You will find out there is a difference...

If your auto never works or plays hard? Yes a regular dino gear oil is fine... Other wise the higher end gear oils are a very good investment... You would be suprised how hot a hard working rearend gets...

 

[m37charlie]

Originally Posted By: drfeelgood
Originally Posted By: Quattro Pete
Originally Posted By: Riz
Rearend Fluid

Sorry, but when I saw this in Recent Topics, I thought it was going to be about some medical condition...


For rearend fluid, I recommend kaopectate or Lomotil.

Dr. Feelgood


Excuse me, but Metamucil (psyllium fiber is generic name) is what is really good for rearend problems of the body type.

Charlie

PS: A Mercedes Unimog U500 (mine) with a camper that weighs a total of ~12000kg, with ~8000kg on the rear axle, 4400kg on front, has a rear diff temp of only 170F. after running 55-60mph all day at about 87F. ambient temp. The diff (2.182 ratio) has only 2.5L of oil because it also has portal gear boxes at the hubs (2.714 ratio), which hold a mere 700ml of oil but run even cooler, only 140F. in the rear and 125-130F. in front. The specs call for Delvac Synthetic Gear Oil 75W90.
I think measuring the temp is really important.
Get a laser aimed IR thermometer. One is certainly justified in using 75W110 or 75W140 if temps are high, i.e. well over 200 F.
What is surprising about my temp measurements is that rear tire temperature can rise up to 150-160F., warmer than the hub portal boxes. The wheels have a huge offset, 6.31" Must be the airflow from the rotating wheels that keeps the hubs cool.