My dealer says the diff fluid for the American Axle differentials is a specially formulated synthetic GL5 75-90 and different from the other GL5 75-90 synthetic fluids. Does anyone know if this is fact. The fluid from the dealer is twice as much as 75-90 synthetic at Wal Mart.

 

I had a long conversation with an American Axle engineer when I first bought my truck regarding fill levels, etc. I told him I would be putting in Mobil One synthetic or some equivalent and he said that was fine. I mentioned it because I specifically said I was not using Mopar brand and he told me Mobil or Redline, etc would be fine. I did not specifically ask him about any special formulation in the Mopar fluid. I will tell you this, I have been using Mobil One 75-90 for 4 yrs. and as of a couple of months ago when I dropped my differential cover, everything looked great.

 

Any fluid that meets or exceeds the recommended GL-5 is fine and will not affect your warranty. I have used 75/90 but DOdge just sent a TSB that if you live in HOtter climates and tow, to use the 75/140. I use Amsoil. I also have used the 75/110 with good success!

 

I can't find that TSB, do you have a number??/ I'm getting ready to do a axle fluid change and would like to know what they consider a 'hot" climate.... I live in VA and tow a 5000lb camper.... do you think I should use the 75/140 fluid??
TIA

 

I think there was some confusion on that issue. I have read (on here) several times that Dodge recommends going to 75/140 on the 1500 model trucks only. Not the 2500/3500 trucks. The 75/90 fluid is supposed to be fine for our trucks.

I am not saying that the 75/140 will hurt it......and it may even help..I don't know. Mine seems fine using 75/90 and I tow heavy and often in a hot climate.

 

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


Also here is a TSB about axle fill levels. But if you look closely at each group in the charts.....ie...Durango, 1500 trucks, 2500/3500 trucks....you will see the recommended fluid off to the side.

On 1500 trucks it is 75w140. ON ours it is 75w90.

 

i use plain jane gl-5 75w140. $23 for 2 gallons. i change it every 10-15k miles. if it looks good when i check in, i will run it another 5k

brett

 

For what it will cost to rebuild the rear end a quality synthetic is well worth it!

BTW I was just at Walmart, there lube is not a full synthetic.

 

75/140......140K miles, hot weather (south TX), and I gross 25K+lbs

 

If he's changing it often it won't matter gear oil is gear oil. When we parked my grandfather's still running '66 F100 farm work truck in the barn several years ago it still had the factory fill dino gear lube in the diff. He thought I was crazy for changing mine and probably is right.

 

Yeah, but probaly that old farm truck does not see highway speeds often (if at all) and hence not much heat build up to break down the diff fluid. But, I do see what you are getting at.

 

Where do you guys get full synthetic? I cant find any place around here but the dealer $$, I may have to drive to Roanoke VA....

 

And thanks for that.. I looked at that TSB but once I saw axle fill levels I didn't pay any attention to the fluid type on there...

 

RP every 30,000 miles. 75-140.

 

Take a look at Amsoil...