Do our AAM axles truly require synthetic?
 

Wow! Last time I bought Royal Purple, I paid something resembling $8.00. I just paid over $19.00 at the local Napa for a bottle of Royal Purple. I'm glad I just needed one to get enough to service my truck. I see that Red Line is still available mail order for about $11 or so, I may switch to that.

This has all gotten me thinking, though... With a 15K service interval, do these axles truly require synthetic? I see that there are several dino G-5 oils available.

Any thoughts?

I use some other brand of synth, like mobil1 or something. 19 a quart is too much. The other stuff is like 10 dollars.

I use Mobile1 at about $10 a quart and I only do 30k change intervals.

ROYAL PURPLE = PAYING FOR A NAME.

save money, valvoline or mobile 1 like said above

Paying for a small company to advertise in all the big publications, and for them to donate their product to every project car or truck done in the last 10 yrs. Mobil

If you are running a synthetic I would extend the service interval to 100k unless you are getting in deep water. If you feel the need to change it every 15k or you get in a bunch of water, I would run the cheap stuff.

Do our AAM axles truly require synthetic?

No, and you can run the engine on sewing machine oil, too.

Just buy the stuff from the dealer and be though with it. Or buy a vehicle you can actually afford to maintain.

I can more than afford to maintain this vehicle. I simply don't like being ripped off, even if I can afford it. If Dodge said the engine oil must be changed every 1000 miles, would you believe it and just deal with it? I hear that GM recommends 30,000 mile maintenance intervals on the same axles that Dodge recommends 15,000 on. Who is correct?

I'm simply not interested in wasting $120 on gear oil every 15,000 miles. If there is a valid reason for that interval and specification, then fine, it's part of the game. If it's just Dodge letting everyone pay two times or four times or however many times the necessary expense so they can have a 1 or 2 % lower rate of warranty repairs, then I'm being gamed and that's not the game I want to play. Fair is a two way street.

Looking at this another way, a Dana 80 serviced every 30,000 with dino oil costs something around $60 to go 120,000 miles, not counting labor. An AAM 11.5 serviced every 15,000 with synthetic oil costs $480* for the same distance. Plus, the labor would be double. Considering that these are supposed to be the toughest and best axles ever put under a Dodge truck, something seems wrong with that picture.


* Assuming apparently now overpriced Royal Purple. Looks like it's going to be Valvoline or Red Line for me moving forwards.

I wonder when the price went up. I paid around $8 a quart a year ago at Orilleys.

I have been running Mobil 1 with no issues. I run it because it is available at just about every store near me. Run whatever you want, just make sure it is GL5.

I would extend the change interval to at least 30k - but only after you have done the initial change. The factory stuff that came out looked bad. I hate to admit it, but I have had vehicles in the past and changed the rear fluid maybe 1 time. Never had one fail.

My owners manual states to change the oil at 30k miles or 15k if heavy towing. I change my rear diff at 15k and the front at 30k because I seldom use the 4x4. Oil required by the manual is full synthetic. Any G-5 75w-90 synthetic will do the job. I use 75w-140 as per TSB if towing in the rear diff.

I change the rear at 30 to 40 thousand miles and I use amsoil 75-110 and the front has 75-90 amsoil and I probably won't change it again as I have the Dynatrac free spin hubs and most of the time the F diff is not turning. Of course if I get into water etc I will change oil in the Fdiff as well.
Jim O

Same as I replied to you in the post you started three days ago. The 15,000 mile heavy towing use drain interval that Dodge recommends for the AAM 11.5" axle is absolutely retarded. So is the 30,000 mile normal use schedule. GM trucks with the Duraturd have the same 11.5" AAM axle that Dodge has and its fluid change interval is 50K.

Use a real Synthetic like Group IV and you can can go 100,000 miles easily on the gear oil.

Totally agree. I still wouldn't run a cheap non-synthetic though, no matter what.

Buy the stuff from the dealer? And pay 3-4 times more for it than if you just went with Mobil gear oil? Just make sure it is GL-5 spec'd. That goes for any other type of gear oil. The dealer stuff is a group III synthetic. Pennzoil used to be the supplier for Mopar. I don't know if it still is or not.

GM is actually 50,000 miles.

The front spins just as much as the rear, its just not under a drive load unless in 4x4. Might wanna check that TSB again. No where does it say 75w-140 for the 11.5" AAM. But.... A lot of ppl run it with better results especially towing heavy in hot climates. AAM says that 75w-90 is all that is needed unless towing at or above GCWR in the middle of the summer in a hot climate.

[QUOTE=The front spins just as much as the rear, its just not under a drive load unless in 4x4. Might wanna check that TSB again. No where does it say 75w-140 for the 11.5" AAM. But.... A lot of ppl run it with better results especially towing heavy in hot climates. AAM says that 75w-90 is all that is needed unless towing at or above GCWR in the middle of the summer in a hot climate.[/QUOTE]

I read the TSB at my dealer back in 2002 or 2003. Do not know the number.

I agree that the front turns just as much as the rear. Based on the load of towing as opposed to the lighter load of not towing and the change interval of 30k for not towing and 15k for towing, I chose to think that the front is not towing and the 30k interval can be used. I also use 75W-90 in the front because it is not under a heavy load.