75W140 Rear Gear oil

[oldhp]

On my 2012 Ram 1500 Express 2WD non-posi the owners manual says to use 75W140 gear oil.
On a 2012 Ram 1500 Express "4WD" it says to use 75W90 gear oil front and rear. On the 2500 and 3500 Rams it says to use 75W90 gear oil.
Why do you think they want the heavier 75W140 gear oil in the 2WD???
Thanks
oldhp

 

[Rand]

smaller axle that heats up more?

 

[2oldtommy]

One may be made by Dana and the other by American axle. The engineer that designed the axle may have a preference. FWIW--Oldtommy

 

[hounddog]

Dana is not used by Chrysler. Dropped by Chrysler a number of years ago. Too many issues. One is American axle manufacturing the other is by ZF manufacturing. The 2wd takes 75w140 full synthetic. Its a ZF axle assembly. Follow your book.

 

[Jim Allen]

Chrysler also has their own axle group "The Gear" (Detroit Axle & Gear) that makes the 8.25, 9.25, etc.

 

[hounddog]

ZF is making the those now if I'm not mistaken. 9.25 has been a ZF for several years .

 

[hounddog]

ZF is making the those now if I'm not mistaken. 9.25 has been a ZF for several years. I just looked it up. Its eiher a AAM axel or a ZF axel.

 

[Jeff_in_VABch]

Unless you are doing heavy towing, it really dosent matter what you use. I would probably use a good synthetic 75W90 and pick up some efficiency unless you tow a lot.

 

[hounddog]

ZF calls for 80w140

 

[Jeff_in_VABch]

Originally Posted By: hounddog
ZF calls for 80w140


Dosent really matter if it's a 9.25. They are all the same.

 

[phillipmcmillian]

i was reading everybodys threads i was changing my rear diff. i thought since i was at Walmart i would use the super tech diff fuild.man i better not i didnt know anything about the product. all ways a chevyman on trucks and cars. but i bought a 2005 ram brand new. already replaced the motor at 35000 miles anyways. i didnt some cheap fuild jacking it up the rear end up. went to local auto store and got valvoline 75/140 at 69000 miles just changed it it was clean as new oil with no metal shavings good uh