1720D FWD Problem

[farm22hills]

I have a 1720D which I love but for some reason the front end part of the 4 wheel drive just stopped working. I'm pretty ignorant of transmissions but, using a service manual, I did figure out how to remove and replace the transmission driveline between the rear and front gear boxes without losing those pesky little ball bearings. I pulled the rear box and checked the assembly and everything looked like it was in order. I also inspected the external part of the connection with the front drive and the only strange thing (I think it was strange) was that the drive spline turned freely without any resistance. I would have thought the front axle drive gears would always remain engaged since it appears the 4WD is engaged by the meshing of gears in the rear gear box. Anyway, before I go to the trouble to disassemble the front axle, I thought I would ask if anyone might have a clue what I may be facing- Is it worth the effort or should I look for another tractor? I hear front transmission parts are hard to find.

 

[gbirky]

If you can turn in input shaft to the front differential and neither of the front wheels turns, then you have something wrong with the front drive. You are correct, the front wheel drive is engaged within the transmission, not at the front axle. I have heard of cases where the bolts that hold the ring gear on the differential have backed out causing the symptoms you describe. It sounds like the input shaft (and pinion gear) are not engaging anything in the differential.

It is definately worth dis-assembly to determine the problem. I would try not to dis-assemble the outboard final drive mechanisms until you determine whether the problem is in the differential (center section) or not. The final drives can be difficult to get back toghether.

 

[farm22hills]

Sounds reasonable. Thank you. The diagram of the internals of the front axle in the manual will come in handy for this job. I just hope there are no other little surprises like those ball bearings!