i went to take the bigbear for a ride today and noticed there was a bunch of dark fluid under the differential...i took it for a short ride and everything seemed to be working fine...what should i do?

 

Well, it sounds like you might have a seal or gasket leaking in the rear diff. 1st, check the oil level to be sure it's full and fill it to specs if not. You may even want to change out the oil completely. Then clean off the differential really good so that you'll be able to tell where it's leaking when it starts again.

If it's not dripping out continuously, you can still ride it, but I'd get the seal/gasket replaced as soon as possible so you don't run the risk of getting water or dirt in the gearbox, or running too low on fluid, that will cause damage.

Also look at the rest of the motor and shafts connecting to the differential to see if there's possibly a leak somewhere else that might be blowing back or running onto the diff.

 

alright...ill check that out as soon as i can..do you have any idea where i could find some differential oil?...and what do you think could of caused the gasket to just go out if thats what it is

 

You should be able to get the right gear oil for your BigBear from a Yamaha dealer or any cycle shop probably.

If you want to use something other than the Yamaha brand, search on this site for, "gear oil" or "differential oil" or variations of that, there's tons of recommendations from others here. It's a matter of personal preference in the endrun. AMSOIL and RedLine are two of the more top of the line synthetic gear oil manufacturers if you want to go that route. But you'll have to research their websites and find a local dealer near you. Or just check your manuals specifications (if you still have it) and look at some auto stores, WalMart or places like that and they might have the right stuff too.

As for reasons of gasket or seal failures, there are many. Age, pressure, vibration, impact, loose bolts, dirty oil, anything of this sort can cause a gasket or seal to fail over time. Pressure, dirt and age are the three big reasons, in my opinion anyway, but I'm no expert on the subject.

Be sure to check your 4x4 out real good. You want to be sure the leak isn't deferred, as in coming from somewhere else, just to be sure.

 

ahh..alright thanks ill probably just stick with the yamaha stuff..what a pain..everything was goin fine until this lol...thanks for your help

 

Your welcome. If that's the only problem you've had on a 2001 BigBear so far, I'd say you're doing pretty darn good.

 

WOAHH!!!!!! tell me more!! this is the first i have heard of this...

 

ok...the bashplate in the back got hit up around the bolt i guess...and the vibrations from that must of loosed up the screw or maybe the dealer didnt tighten it enough..oh well its good not