1720d 4wd problem

gskeeters · Jul 9, 2016

Every time I remove the shaft and replace the ball bearings the 4wd works for a short time then stops. I remove shaft and replace ball bearings and same thing. Any ideas on what needs replaced? Is there any type of modification I can make to prevent this or do I need to replace something?

Thanks

winston1 · Jul 9, 2016

Assuming you are talking about the balls on the drive shaft coming out. If so, have you checked making sure all components showing on this nice Hoye drawing are in place? Spring, etc. that holds tension. 4WD INTERNAL ^: Yanmar Tractor Parts

gskeeters · Jul 9, 2016

Thanks, I'll go through and insure everything is in place. Is it possible that the spring is weak and allowing it to slip causing the balls to fall out?

winston1 · Jul 9, 2016

I can't answer that. Seems it could be possible. Do all your components look ok, no rust or evident wear spots?

gskeeters · Jul 9, 2016

It's all there and I can't see anything that looks worn beyond normal. Pulled the shaft, cleaned it all up. Installed new metal balls packed in grease and was very careful to insure they stayed in place when I reinstalled. Took out and began moving some gravel I had delivered for my drive. Worked about a half hour and when I was backing up in some deep gravel.... It quit working again. Can spin the shaft so the ball bearings have obviously fell out again.
Frustrating and thinking maybe the yokes either on the shaft or front diff are worn out. The rear bearings appear to be in tact each time I pull the shaft... It's the front:forward one that are out

winston1 · Jul 10, 2016

Just reaching out there. Any excessive wear in the front axle pivot bushings or shaft. #s 2 and 26 here? 4WD EXTERNAL ^: Yanmar Tractor Parts
Very good thread by a lady that might help. She has some great pictures. Clunking in 4WD - what could be wrong? - Yanmar Tractor Support Message Board

gskeeters · Jul 10, 2016

Awesome link. Thanks. I thing from the looks of the spline that mine is also showing wear from bearing spin. I can do some welding and grinding and fix it for sure. Thanks for the help!!