# big bear rear end



## JGBigBear

i went riding last night and i heard a weird noise in the rear end of my fourwheeler when i would slow down in a high gear it wasnt to loud but i could hear it...i cleaned it and checked the differential oil today and it is a brownish color...all of my gears work good...any ideas on how water or mud is getting in there? and what weight oil do i use in the rear end


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## 09 griz

leaking seal or vent line i use 75-90 in mine


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## JGBigBear

its not leaking out at all......could i use some lucas transmission fluid with stop leak?


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## 09 griz

if its not leaking then its the vent line


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## JGBigBear

the oil in the rear end was a really dark color the oil in the front end was a really light color...not sure what its supposed to be...


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## 09 griz

might just need to be changed the rear is darker because you use the rear more unless you stay in 4 wheel drive all the time would be milky color if you had a leak i ride hard so i replace after every 2 rides oil is cheap diff is not


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## Josh

My old honda would look muddy in the front from water and mud getting inside. Your vent line would be my guess.


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## grizzlyadams

You could have a bearing going out?


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## JGBigBear

maybe so i dont know how to check if the bearing is going out i changed the dif fluid and im gonna check on them vent lines i didnt even know there was vent lines on the dif...


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## JGBigBear

well i changed all the oils and everything is good except when i am in third gear or 4th and i slow down right before it stops i can hear a little knocking type of sound im not sure if i am hearing things or what but other than that i dont have any problems??


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## cooter1j

most likly it is the pinion seal. witch you got to pull it from the swing arm to check it. if it is leaking you might not notice it cause it is going in the swing arm tube. my buddy had this same issue. and the bolts that hold the swing arm to the frame gave usalot of problems so be careful with them and good luck 
and check it out before its to late. i just blew my rear in my 2007 bb 400 independent rear and i cant find one used or under $500.


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## cooter1j

oh and that knocking sound is either your bearings or your ring and pinion slaming together from deaceleration. and your not hearing things ive been there and ignored mine for about a month and then mine blew


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## JGBigBear

so once it blows i have to get a whole new rear end?


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## cooter1j

not necessarily it depends on how bad you destroy it. if your still hering things you need to pull it apart and check things out. see if you bearing have any play, and see if the ring and pinion has unusual wear. if you let it go too long it will be very costly to repair. i cracked my case where the pinion bearing sets so mine is not repairable.


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