Has anyone switched the a synthetic rearend lub? I see the owners manual recommends a synthetic if you do a lot of heavy towing. I'm thinkin about Amsoil. Comments or suggestions?<br><br>Ronster

The reason for no friction addative it that their are no longer clutch packs in the posi to my understanding. They now use a worm gear type of posi, much better unit, don't have the wearing out problem.

Ronster<br><br>Read page 340 of the owners manual<br><br>Front and Read Axle Fluid 2500/3500 Models<br><br>GL-5 SAE 75W-90 Synthetic. Limited slip axles DO NOT REQUIRE a limited slip additive.<br><br>Hope this helps, it is already there (synthetic) ;D<br><br>Hunter

Hunter, I don't have my owners manual. Dealer still owes me, but I got that info from my 2001 manual and bought Amsoil to put in the M80 Dana and I was just thinking of using it in the 2003. I'll assume you're correct and I'll check out the page you're referring to when I get a 2003 manual. Thx!<br><br>Ronster

Hunter is correct, synthetic GL-5 75w-90 is required for the rear axles. Mine came from the factory that way.

Even the service guy at my dealers marvels &quot;how in the hell can Dodge use synthetic right off the bat?&quot;<br><br>Got me!<br><br>But I am liking it a lot ;D<br><br>Hunter

Hunter,<br><br>Contrary to popular belief, requiring synthetic and installing it at the factory does not help the &quot;bottom line&quot;. they could install dino oil in the axle and save a few bucks per vehicle. Doing so could cause component failure the day after warranty expires like the Ferds do. [laugh] Of course it would not do The reputation of the Dodge boys any good. Dodge owners are much smarter than Ferd owners who just don't seem to get it. [laugh]

Put the Mag Hytec read end cover on mine at about 21000 and it holds near eight quarts of AMSOIL 75 90 now. Got over 110000 presently. Pull up to 26000 pounds some times. No problems.

DC has required synthetic oil in rear axles since mid-year 2002, even though the '02's have a different one than the '03's. &quot;Too many failures relating to large loads, high summer temperatures, and high torque from the CTD and the V-10 engines,&quot; a DC rep explained to me when I was summoned to the dealership to have mine replaced.

GP