I 1st posted this in Drivetrains, Tires and Suspension, but it was suggested I might get more response here in the Yamaha section.

I just got a new 2005 Kodiak 450 4x4. I love it so far, great machine. I have a question on the differential gear oil. The manual recommends to use SAE 80W-90 Mt-1 GL-4 (or GL-5 or 6) hypoid gear oil. I'm sure GL-4 is what is in it right now from the factory. My question is, if there is GL-4 in it now, can you simply add a GL-5 rated oil to it if it's low, or should I not mix GL-4 with GL-5?

I read some other posts saying GL-5 or 6 is ok to use in the 450, but I don't want to mix GL-5 with GL-4 oil if that will cause any problems. It's a bugger trying to find GL-4 specifically, other than at a Yamaha dealer I guess.

Thanks for replies.

 

I had this same question when i got my kodiak too. The owners manual says gl-4, and thats all. I since found out, the gl rateing isnt like the oil rateing, where newer, is backwards compatable with the previous ratings. Gl-5 may or may not be the correct fluid. I settled on using only a fluid which has the gl-4 rating on the container, which can be hard to find. I found amsoil 75w 90, fully synthetic, and its rated gl-1 thru gl-5, and it was only a buck more per quart, than regular gear oil.
Hope this helps, welcome to the forums.

 

Thanks for the reply Hondabuster. I'll try and find a place that sells GL-4 rated oil. You mention synthetic oil, so I guess a synthetic is ok to use in the 450 diff?

 

The only difference in oils, is in how they are made. Crude is refined to get regular oil, and synthetic is built from the molecule up. They end up being chemically the same, its just that the synthetic has no impurities, and all the molecules are the same size, as opposed to some byproducts which cant be refined out, and irregular and odd shaped molecules of reg oil.
When theres a small price difference, its worth it to go for the synthetic.
Its tough to find gl-4 , most are just labeled gl-5.

 

Call me crazy but I don't care too much about the type. As long as you don't mix two different types, you should be fine as long as you use a good quality rearend oil. (This assumes that the warranty has ran out, otherwise go stock so as not to void the warranty) It's not like they are going to send the police after you for using the wrong oil. And if and when the parts wear out, the warranty will be long gone. In mine, I just make sure I don't mix different types and keep it at the correct level. Haven't had any problems yet and it has been on the road for almost 7 years. But, to each his own and do what you feel comfortable with. It is a large investment.

 

Thanks for your replies [img]i/expressions/face-icon-small-smile.gif[/img] , you've definitely helped me out.

I've been checking out the amsoil website and decided I'll go with using their SAE 80W-90 synthetic gear lube (mainly because the 450 manual recommends the SAE 80). Says it's compatible with most limited slip differentials, and can be used where a GL-4 rating is specified. But, (quoted right off their site), "If limited slip differential chatter occurs, add AMSOIL Slip-Lock™ friction modifier additive". Hmm, a bit concerning for the front diff, but I'll try it anyway.

amsoil says you can mix this with other oils, but it will of course degrade it's max performance ratings. I'll just change it out fully at the 1st maintenance schedule so it's done right.

 

Why dont you just drain it. It cant hurt and will get any metal shaving out. I have been using Mobil1 synthetic gear lube. I have had no problems and you can find it at any auto parts store[img]i/expressions/face-icon-small-happy.gif[/img]

 

For one, its against the law for the dealer to deny a warrentee claim because you didnt use their oil, or filter. As long as the label states the correct weight and rateing....its the correct stuff. Brand doesnt matter, nor does synthetic vs dino.

There is no problem with mixing synthetic and dino oils...they even sell it now, its called blended. It wont hurt a thing by adding a bit of one to the other, or even mixing 50%.

Ive been using amsoil in my front end, and so far no chatter or problems, and actually the service manual doesnt call out for a friction modifier to be added to the front diff., so what goes in back, can go in front.

I looked at using the mobil one stuff, but its only rated gl-5, and their website and dealers, wont say its a replacement for gl-4. Its probably not gonna hurt anything, but id rather have the label say correct for gl-4.

 

I disagree with Hondabuster about mixing oils. It's not a good idea because different mfgs put detergents and addedtives in them that COULD react with another brand. While it may not be the case with all brands and I am sure that you could mix some and have no problems at all, some others could cause problems that really screw things up. Again, it's up to you.

 

Hey why don't you just go down to the yamaha dealer and buy the correct stuff? I did for less than $5 ...Why risk anything for that amount?