I need to change the gear lube. Its the limited slip. Whats a good lube to use and how much is needed? Im thinking this has been asked before but oh well. Also do i need to put any additive in it for limited slip?

 

royal purple, fill it about a half inch below the inspection hole, or a good quality 80-90 gear oil i've used Union 76, massey furgusen permatrans high heat.

 

Any GL-5 rated synthetic gear oil in 75w90 is fine. I have been happy with Mobil 1. I just bought some for $8.99 a quart...about to change mine again.

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I used Valvoline 75w90, 7 quarts i believe w/o additive.

I'd DOUBLE check in your owners manual, All the info is in there..

 

The Manual calls for ONLY 75/90. GL5 Synthetic. Not 80-90. SOME run the 75/140 if you tow in high heat all the time. Amsoil makes a good 75-110 which is right inbetween.

 

Well that's what i run with no problems in AK..

 

Is there a how to for us newbies? What's needed besides lube? Gasket only?

 

i just refilled mine with 80w90 from napa. $40 for a 5 gallon bucket. I added limited slip additive to each differiental. i will be more than surprised if i ever have an issue with it. Theres no new technology that MUST HAVE synthetic oil in those gear sets.

 

Just lube. The gasket is made from rubber and is reusable.

The recommend torque on the bolts is 22 lbs, but be careful, they're prone to snapping off.

MikeyB

 

What the heck you tightening them with!?

 

MikeyB is correct, many owners have snapped these bolts off...

 

Clemson725,

Why did you add limited slip additive to yours? The AAM axles do not require it as they are gear driven limited slips. As for sythetic vs. non why would you not put back a synthetic fluid? If the engineers that designed the axle thought it needed it then why not keep using it? I have run Royal Purple in my truck since it was new and change it every 60K. It looks as clean coming out as it was going in. In the long run using a synthetic fluid is a much cheaper solution. I am at 140K and barely have a wear pattern on my ring and pinions.

Brad

 

The additive doesn't hurt anything. It can only help from grabbing. There is nothing special about the differentials that should require synthetic. I've heard of synthetic eating away at some seals in rear ends that weren't made for synthetic, but i've never heard of the opposite happening. You're more than welcome to put it in. I have nothing against synthetic.

How do you know you'll save you money in the long run? I'll put a bill down that mine is just as tight as yours 200,000 miles from now and i only used about $12 worth of oil to do both differentials. Although at the rate I drive, it'll be abput 15 years from now before I have 200,000 miles.

 

If you want to use non syn fluids then go right ahead as they have worked fine for many years and will continue to. i use them in my other vehicles and they work fine. I am a believer in new technology and most the new syn fluids are superior.


I guess I still dont get the additive thing. You only use an additive if you have clutch material in your diff and we have none. Its funny that you are saying save your money and run the non syn fluids yet you are pouring in an additive that does nothing. Save your money on the additive next time.

Syn fluids will not eat any seals in an axle that was designed for dino fluids. Our trucks came with syn fluids so I am not ever sure why you added that statement. Not trying to bust your ***** here but the facts need to be straight.

 

I used the additive for what the additive is. It lessens friction. Its a peace of mind. I went to 80w90 nonsynthetic which is less slippery as synthetic. Thats the difference in the two. Synthetic molecules are smaller and uniform like trying to walk across bb's instead of baseballs, softballs, basketballs all mixed together. I could have put two or three bottles of it in there for what synthetic costs. The fact is that I don't put my gears in a lot of stress and i doubt that i'd ever have had a problem if i went 100,000 miles before changing it instead of 42,000.

The fact is that I never said the trucks didnt come with synthetic. My statement about it eating seals was wrong. I had my head in the wrong place. It can leak out of worn seals at times that dino oil will not. However, i didn't say that your truck came with dino oil and it would leak with synthetic. The facts are in what i wrote, not what you read.