# Rear Diff Oil?



## xtreme02gt

I know I have seen it on here before, did some searching before I posted this, cause for some reason I can't find the answer....

I was looking to change out my rear diff oil, so I headed up to me local dealer, and they handed me this ( Yamalube SAE 80w-90 )( GL-4, GL-5 ) and said to use this.. So I bought it, but im still not sure.. 

So I am asking the MIMB pro's... Will this stuff work in the rear diff?


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## gcfishguy

Rear takes hydraulic fluid for the sealed brakes....THD not 80w90, which is 'gear oil'.

(This is assuming we're talking about the Brute)


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## jrfonte

I'm pretty sure that is not what goes in a brute rear diff it should be wet brake hydraulic fluid like what goes in tractor trannys


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## bayou_boy_22

i went and bought some tractor hydraulic fluid from autozone.


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## NMKawierider

gcfishguy said:


> Rear takes hydraulic fluid for the sealed brakes....THD not 80w90, which is 'gear oil'


Exactly -- DO NOT use gear oil in a Kawasaki rear gearcase/diff(not realy a diff). Get the Kawasaki wet brake oil or tractor hydraulic oil because it has the additives for the ring,pinion and bearings where most regular hydraulic oil doesn't.


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## gcfishguy

nmkawierider said:


> Get the Kawasaki wet brake oil or tractor hydraulic oil because it has the additives for the ring,pinion and bearings where most regular hydraulic oil doesn't.


Glad you mentioned that....for those that don't know, THD stands for 'transmission/hydraulic/differential'....
I always saw the first two letters and assumed "Tractor Hydraulic Something" without thinking about it....actually never thought about it until you posted that. Thanks!

I'm using the stuff from Wal-Mart. 4L cost me less than the 1L that I bought at the dealer for my first service....

And if you're doing the front diff, it's engine oil...10w40 recommended. 
I was tempted to use synthetic for the winter (gets WAY cold here) but the jury's still out on that because of the diff lock. 
Some say yes, some say no.....

Edit - not to split hairs, but since the D stands for differential, wouldn't any THD be okay for a ring and pinion?


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## acesilverbask

*tdh oil*

you need the tdh oil for the rear diff because it has a wet brake built into it . if you use any other oil the brakes would chatter and eventually fail.


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## Hi-Tower

I use kawi's wet brake also


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## NMKawierider

gcfishguy said:


> not to split hairs, but since the D stands for differential, wouldn't any THD be okay for a ring and pinion?


I'm sure. I just said "Tractor" because the book refers to it that way. For me its the Kawie wet brake oil...only


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## drtj

I got a question for yall. Why do the seals leak so much more on the front diff compared to the rear diff? I have checked & changed the rear several times with no sign of water in it. The front is a completely different story.


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## Roboquad

My question is why are you using brakes.:flames:


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## brute for mud

i use brakes to slow down when i trail ride


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## NMKawierider

drtj said:


> I got a question for yall. Why do the seals leak so much more on the front diff compared to the rear diff? I have checked & changed the rear several times with no sign of water in it. The front is a completely different story.


I personaly think the seal issues with the front diff is part water and part the fact that the driveline is fixed or "without U-joints" that help with the movements and flex of the frame, engine and diff under touque. I think that puts undue stress on that input shaft, its bearing and the seal. The driveline does give a little, but not near enough. It needs u-joints like the back has IMO. Unfortunatly it doesn't have enough angle for that so maybe some kind of CV or rubber torque joint...something so its not a hard-link to the diff.

Now as for why water always gets in to it.. I am unclear but it does...a lot. It has the same number of case gaskets,axles seals and driveline seals. It has a vent that runs to the pod just line the rear. It does have one other thing the back doesn't have and that's an actuator. Is there a way for water to get in through any part of that? Maybe, but some of you guys have pulled that off more often then most people...including myself. Can it get in through the wiring gromet..or any where else?


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## xtreme02gt

nmkawierider said:


> Exactly -- DO NOT use gear oil in a Kawasaki rear gearcase/diff(not realy a diff). Get the Kawasaki wet brake oil or tractor hydraulic oil because it has the additives for the ring,pinion and bearings where most regular hydraulic oil doesn't.


 
Can you tell me what you use? And where you get it?


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## xtreme02gt

Will this stuff work from Tractor Supply?

http://www.tractorsupply.com/vehicl...-tractor-trans-hydraulic-fluid-2-gal--0806383


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## NMKawierider

xtreme02gt said:


> Will this stuff work from Tractor Supply?
> 
> http://www.tractorsupply.com/vehicl...-tractor-trans-hydraulic-fluid-2-gal--0806383


 
Yes. Good stuff. I use the Kawasaki wet Brake oil from the dealer.


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## xtreme02gt

Well I guess I will go to tractor supply then... Cause the dealer sold me some yamalube 80w gear oil. So they dont know what the hell ther doing. It also took them 2 1/2 week to adjust my valves on my yfz450. I really need to learn how to do that myself.. anyways I'll just go to tractor supply this weekend sometime... 

Thanks man!


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## drtj

nmkawierider said:


> I personaly think the seal issues with the front diff is part water and part the fact that the driveline is fixed or "without U-joints" that help with the movements and flex of the frame, engine and diff under touque. I think that puts undue stress on that input shaft, its bearing and the seal. The driveline does give a little, but not near enough. It needs u-joints like the back has IMO. Unfortunatly it doesn't have enough angle for that so maybe some kind of CV or rubber torque joint...something so its not a hard-link to the diff.
> 
> Now as for why water always gets in to it.. I am unclear but it does...a lot. It has the same number of case gaskets,axles seals and driveline seals. It has a vent that runs to the pod just line the rear. It does have one other thing the back doesn't have and that's an actuator. Is there a way for water to get in through any part of that? Maybe, but some of you guys have pulled that off more often then most people...including myself. Can it get in through the wiring gromet..or any where else?


 
The main one that leaks on my front diff is from the motor. So I see what your talking about with the u-joint. 

Ive only had my actuator off one time so I really dont know about water getting in there. That may be worth looking into when i go to having trouble with it. I'm a firm believer in if it aint broke dont fix it. I dont mind changing the seals or oil in the front diff. Next time i change a seal or fluid I will take a closer look at the actuator. If it lets water in it should let oil out. I know it wont leak out as fast but you should see some kind of evidence of oil leakage. Right?:thinking:


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## NMKawierider

drtj said:


> If it lets water in it should let oil out. I know it wont leak out as fast but you should see some kind of evidence of oil leakage. Right?:thinking:


You would think so, but maybe where it is located it doesn't. How about the shaft seal on the diff lock? There's another place. I have never had the water problem but so many have it makes you wonder.


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## brutemike

Imo the water gets in thru the seals on the cv joint because of the set up with bevel gears in the front diff esp. when the bike is lifted.It puts a harder angle on the cvs there for wearing on the bevel gears and the cage they ride in wearing them out faster.I that cv doesnt sit in there perfect then the seals wont ride on the cup of the cv all the way around it if you know what i mean.I do agree with NMK on the front drive shaft too.


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## deadman inc

I hardly use any of my brakes to slow down or anything on the trails. The engine brake does everything plus it does save the life of your brakes believe it or not...


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## MeanGreenMan

Oil info is in the Owner's Manual.


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## 09_650i

i use CASE HY TRAN in the rear diff it's not too expensive and is made for wet brakes.


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