Synthetic 75w-90?????

[JARichard]

I know most people here use AMSOIL. But I really do not like mail order. I have to fit my maintenace in when I can. I wouldn't mind using it but I can not find some one in stock. As a matter fact I went to 8 auto parts stores to get enough to do both diffs last time. What are you guys using? Where are you getting it? How often are you changing it?

I dont pull anything but a 4 wheeler trailer. The most weight my truck sees is at most 3000 lbs. of steel in the bed.

Any suggestions?

Thanks!

 

[Bertram65]

Mobil1, got it at Autozone, although I used Amsoil at the first change could not get it from the speed shop when I wanted to change it the second time. I changed it once at 1k miles and again at 12k, I will change it again at 30K, I changed it at 12k because I wanted to put on a new diff cover, otherwise I would have waited till 15k.

 

[miller_wb]

There is a dramatic difference in axle oil change frequency between the two maintenance schedules. I decided on every 25K. It does seem like overkill to replace the axle fluid with full synthetic every 15K especially for the front axle. My driving habits put me somewhere in the middle of the two schedules. I did replace both front and back at 25K. I mail ordered the Amsoil.

 

[Tony T.]

Changing Gear Oil

I replaced front an rear gear oil at 15,200 miles an used 75w/90 Castrol Syntec Full-Synthetic Gear Oil. Got it at O'Reilly's Auto Parts, but they did have to order it for me, with only a couple quarts showing on the store shelf. Plan on going longer next time to change, because I don't tow that often here lately. Another good reason to change would be due to condensation for the ones that don't tow anyway even though the owners manual shows a wide range between A&B schedules.

 

[thejeepdude]

I've found Mobil1 gear oil at Autozone / Kragen / Schucks type places, but I prefer to use Redline. There's a distributor about 10 miles from my house, so it's not that far. You can use their website to see if there's a distributor near you. It shouldn't be too hard to find a local Amsoil distributor either, as long as you're not too far out in the boonies... certainly more cost effective than shipping the oil, unless you're buying it by the drum.

 

[JARichard]

I have a 10. 5" rear and 9. 25' front. How much should I get?

I think a gallon and a quart? Am i right?

 

[badams1]

Mobil 1 75-90w GL 5 is as good as it gets and you can buy it almost anywhere.

 

[ACerf]

I just purchased the Mag-Hytec Diff cover. I am going to put in Amsoil 75W90 2000 series oil. I have never used this stuff before. But most people seem to think that this is about the best, and holds up best under high heat conditions. It is also possible that I will not need to add any modifier to the oil. This I heard from the local dealer was a problem with the Mopar Gear Oil. Some vehicles needed it some didn't!

 

[Bertram65]

Did the Mag cover you got have the revised O-ring for the Dodge axle? Do a search, if it is not you might have leaking problems.

 

[gonzo2]

No friction modifier required on third gen ls axles.

 

[CSilkowski]

Are the Mobil1s, Castrols and Amsoil synthetics better than the stock Mopar synthetic? I will be installing a Mag Hytec this weekend and not sure what to use. Jeff at Mag suggests the dino oil he sells is the best but I know are rearends suggest synthetics.

 

[Bertram65]

The AA rearends require synthetic. That's funny that he would suggest dino, what is his logic for it? the fact that he sells it?

 

[CSilkowski]

Probably because he sells it. He just said it was the best, but didn't explain why.



Are the aftermarket synthetics better than Mopar? I know a lot owners have had problems with their AA rearends whining and have been taken in for warranty replacement. I have not had any trouble with mine for 25k miles but don't want to do anything to jeopardize that.

 

[mberry]

IMHO, Almost any aftermarket synthetic is going to be better than the Mopar stuff. I have had really good luck with Royal Purple in my truck diffs and my boats' sterndrive.



When the '05 gets here, I am going to use Amsoil in everything.

 

[CSilkowski]

Thanks. I found a local performance shop that had a case of Redline 80w-140 in stock so I took it off his hands.

 

[Bertram65]

Whatever comes in the Dodge is as good as anthing out there, if it meets the GL-5 spec that is all you need.

Watch out putting anything but Mercury oil in a sterndrive. If you talk to anyone who works on them or is involved with high performance they all run the Mercury high performance gear lube, there is nothing better for a sterndrive.

 

[C Schomer]

The 75w90 that came in my 97 was pitch black and burnt badly at 9k miles. I tried AM 2k 75w90 for 12k miles and had problems - gear wear and noise. Then RP 75w90 and it did better - noise went away. I didn't think my 7200lb 5er was "heavy towing" but I decided I was cutting it too close by using 75w90. I eventually worked my way up to RP 85w140 for my dana 80. Craig

 

[adsharpe]

Using Shell Spirax S 75W-90. I haven't towed yet so I won't change it for a good while. It is rated by the big truck folk at Eaton and Meritor, etc. for up to 650k.



I get it in 5 gallon pail at Shell distributors for less than 5 bucks a QT.



The Mobil -1 stuff ain't rated for mileage by any large truck component manufacturer.



I also use it in my Cherokee 4wd.



If you run in water alot (La, MS, TX Fl) change it frequently.



The oil is cheaper than a new rear.

 

[ACerf]

Originally posted by CSilkowski

Thanks. I found a local performance shop that had a case of Redline 80w-140 in stock so I took it off his hands.

Don't you think that 80w140 is a little thick for the rear?

 

[ttreibel]

Originally posted by ACerf

Don't you think that 80w140 is a little thick for the rear?

If you tow a lot and don't live in North Dakota it is the best choice. I am using 75-140 made by Royal purple in my Rear. AA even recomends it in high GVW aplications