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08 Bruin front diff 4wd not working

ken0la

Pro
Joined
Apr 13, 2007
Messages
138
Location
NWestern ON
Country
Canada
Snowmobile
NONO
Indicator light comes on, servo/actuator makes it usual noise but not locking in front diff. I'm thinking as the servo makes its noise when the 4wd button is activated that the "shift shaft" pin is broken. I've had this machine since new and this is the first issue with the machine, just wondering if anyone else has had a similar issue with the yamaha 4wd servo system.
Searched the site, and read post after post but can't find any related items which seems weird, surely I'm not the only one?
 

Ok so it appears the worm gear (pushing 4x4 button) is either not going far enough forward to lock onto the drive shaft, or the drive shaft (within the transmition) is having an issue moving forward enough to engage the front diff.

You can move the drive shaft forward by hand and then it locks onto the front diff gears. You can also move the worm gear slider by hand to fully couple the drive shaft, both engage the 4x4 function, so is this a timimg issue with the 4wd servo or an issue with the drive shaft/transmition?

Someone... Anyone...
 
Ok so it appears the worm gear (pushing 4x4 button) is either not going far enough forward to lock onto the drive shaft, or the drive shaft (within the transmition) is having an issue moving forward enough to engage the front diff.

You can move the drive shaft forward by hand and then it locks onto the front diff gears. You can also move the worm gear slider by hand to fully couple the drive shaft, both engage the 4x4 function, so is this a timimg issue with the 4wd servo or an issue with the drive shaft/transmition?

Someone... Anyone...

Could it be a voltage issue? Isnt that a electric servo that moves that?
 
Servo does make its usual noise and 4wd indicator does light up. Have also watched the gear turn with the servo removed from front diff but still connected to wire harness.
 
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Servo does make its usual noise and 4wd indicator does light up. Have also watched the gear turn with the servo removed from front diff but still connected to wire harness.

I know that you do have to move the unit FWD a bit before it will mesh and engage completely sometimes. But its not engaging at all?
 
That is correct, not at all, also of note, the driveshaft can be stopped by hand, should it not be turning all the time!? I'm leaning towards something in the tranny at this point
 
That is correct, not at all, also of note, the driveshaft can be stopped by hand, should it not be turning all the time!? I'm leaning towards something in the tranny at this point

I suppose its not longer under warranty?
 
ouch. from what i remeber that is a gear to gear transfercase. hopefully the spline just stripped in the yoke.
 
Ok so took it into dealer as I'm in over my head on this one and they stated that the drive shaft is stripped. They wanted 8-10 hrs to fix as they have to lift the engine out for the repair. As the cost of shop rates are way over my pay scale it looks like I now own a 2 wheel drive atv. I see a new quad in my near future and it's looking like a can am with their 5yr warranty and price there is nothing else, bang for buck wise.
 
I cry bs at pulling the motor. I did my uncles shaft by pulling the skid plate, the shaft guard and taking the mounting bolts out for the front diff. I then pulled the transfer case end joint apart in the bike. It gets hazy from there as this was 7 years ago but I did it without pulling motor. Also helps that his bike has rediculous mileage on it and I have changed the joints fairly often for him.
 
I cry bs at pulling the motor. I did my uncles shaft by pulling the skid plate, the shaft guard and taking the mounting bolts out for the front diff. I then pulled the transfer case end joint apart in the bike. It gets hazy from there as this was 7 years ago but I did it without pulling motor. Also helps that his bike has rediculous mileage on it and I have changed the joints fairly often for him.

Interesting, how long would you estimate for such a procedure?
 
i did it after work over 2 days, so i would say between 4-6 hrs if the skid plate comes off nicely. mine/his is so bent that it can be a pita to get the bolts to come out.
 
i did it after work over 2 days, so i would say between 4-6 hrs if the skid plate comes off nicely. mine/his is so bent that it can be a pita to get the bolts to come out.
Thanks for the info, I've got a friend who is much more mechanically inclined than I and he is into it, so we will see.
 


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