I had this issue recently and fixed it by replacing the splined sleeve that joins the driveshaft to the rear diff. It had the splines worn off. I went for two rides since and on the second ride the rear wheels stopped turning. I was able to get out of the bush by using my 4x4 however i couldnt go fast and the steering was awful.

1) Could I have damaged the same part? If so would there be an easy way to tell? Last time i had a buddy deduce that this must have been the issue just from my description of what happened. Ordered the part, changed it and it worked. If it is the same part, how could this have happened? Is there something that could have been overlooked during the repair?

2) Are there other issues that i should be checking for that could have caused my rear wheels to stop working? I have a hard time believing I could have damaged the new part already - but then again you never know with these old bikes.

Thanks in advance!

 

I've had to replace a few of these couplers on the 325 and 425 Magnum because most people either didn't know they were there or had a grease fitting. If another coupler failed I'd think the prop shaft would just grind and slip. One way to tell is to jack the rear end up,have it in neutral and try to spin the rear tires. If it's really locked up,this could be bearing or ring and pinion problem in the rear gear case.Other wise the wheels and prop shaft would turn under normal conditions. This was another item that a lot of people let go dry or didn't change fluid often enough.

 

so it is definitely an issue with the rear gear case. I can here a grind inside when pushing the throttle. Prop shaft is turning and the wheels aren't.

What is the best way to diassemble it in order to find the part?

 

Easier to just leave the rear swing arm in place,remove the caliper,pull the left drive shaft yoke and other parts to be able to pull the drive shaft out. Then wiggle the diff out from the prop shaft. Parts break down shows enough how to take the rear diff apart along with the pinion shaft.

 

I was able to get the wheels and rear diff off. However now I'm second guessing if the issue is a problem with the diff. When the bike was jacked up, I started the bike and the tires moved fine. Once back on the ground, the tires didn't move.

Once I remover the rear axle, if I grab the sleeve coupling I can turn the shaft fine.

Could there be another issue at play here before I take the gearcase apart?

 

If the prop shaft splines or the rear diff pinion splines are worn down,the wheels may turn ok with the new couple while in the air with no load on it. Under a load the coupler may still slip at either place.Inspect the splines closely.