It's time for my first oil change. I've read all the posts about engine oil, but what are you guys using in your front diff? Are you using synthetic?
I've heard that synthetic might make the front diff. slip. Is there any truth to that? Again, thanks kodiak1

 

Synthetic is thinner at low temps, so it makes the diff slightly less stiff. Makes the steering easy.

I used 20w50 synth in the front diff and it is a touch thin, I am thinking about using 70w90 synth.

I first noticed that 20w50 dino oil was nice in the summer but horribly stiff in the cold so I will never put dino oil in it again. I like the synth oil's more consistent viscosity.

 

nyroc, thaks for the reply. i think I am going to use the Amsoil 0w-40. I hope it is not to thin. Please check out my other post about "reverse light and override". Your thoughts on this would be appreciated. Thanks, VIOL8TR

 

Nope, that is too thin. From other people's experience, it won't hurt your machine, but i think your diff will be too loose. At least get the 20w50 (mobil v-twin).

I read that other post, and almost replied.

I do believe you went too far. if you turn the idle up a little high so it causes the gears to clack a little, idle it while adjusting the lever so you can see where the gap between low and high is. Place that gap halfway between L and H on the shifter. It is also possible (less probable) that you need to adjust the shifter range. That is the adjustment on the shift lever itself. You'll see.

 

my front diff is perfect with the amsoil 0w-40 [img]i/expressions/face-icon-small-happy.gif[/img]

 

Thanks for your help guys. I think I will try the Amsoil in my wife's P-650. She is very small and might benefit with easier steering. Also, nyroc do you think the full power thing in reverse is also because the shift linkage is too short? Again, thanks for all your replies. VIOL8TR

 

Yes, I think the rod is too short, unless you somehow pulled the reverse wire off.

You may not even notice the difference with the diff oil you put in.

I have actually tested the unlocked torque of my differential. I never tested amsoil 0w40 in my diff, but I believe it is thin enough to cause the diff to be too loose since I noticed that even 20w50 synthetic reduces the unlocked torque. Although this can be adjusted to compensate for lighter oil like 0w40, you are probably better off in the long run to use a heavier oil and not adjust the diff lever to compensate (unless you never use the locker).

The Limited slip diff clutch torque is supposed to be 11-14 ft-lb without pulling the diff lock lever. You check it with one wheel off (in 2x4), and the other one on the ground. You put a torque wrench on the spindle nut of the side you took the tire off of. Turn torque wrench to read how hard it is to make the diff slip.

The diff lock is supposed to take 116ft-lb or more to cause it to slip when pulling the lever. Place a heavy person on the ATV to help hold the othet tire down, but don't grab the front brakes.

 

I run 10W40 Castrol Dinosaur Doo-Doo. Works for me................................

 

Actually, trx450, 10w40 dino doo doo is probably just right for the front diff. Mine worked just fine with that in it.

You can use a 10w40 synthetic to replace a 10w40 dino oil in an engine where the oil is 180 degress or so. But, replacing a 10w40 dino oil with a 10w40 synthetic in a cold gearbox is just plain using the wrong viscosity. I do not mean to say that it will hurt it, I have no proof of that. Maybe it will, who knows. But it makes the diff slip easier.

I used to complain about hard steering in my 650. Using 20w50 synth in my diff fixed that problem. Now it steers easier. It was awful bad hard with 28" mudzillas with the 20w50 dino oil, with synth it was a lot easier. With the 26" mudrunners, the steering wasn't bad at all with the 20w50 oil, and now with the synth it is extremely easy. Tires make a difference, but so does the diff stiffness.

Next time I change, I will try the 70w90 synth and do a diff lock torque test with it.

 

Thanks for all the replies.