Broken driveline?

Sun Jun 29, 2014 7:27 pm

So I'm to the point of putting things back together on this 47 Cub. When I started, it was for sure that it had a broken crank. I completely tore it down.. have a new block waiting.. plenty of cleaned and primed parts, new gaskets etc.. Now I have the final seals and bearings replaced I put them on the torque tube and started turning the drive shaft in the bell housing and the left side final does not turn. The right does.. I can hold either final/hub still and with it in gear and still turn the drive shaft by hand, sounds like something giving way or dragging in the torque tube/transmission when I do this. I can turn the left hub and the shaft in the bell housing turns but not vise versa. I pulled the shifter and I can't see any broken gears or metal, no broken metal from the rear pto cover either.
I hope I'm making sense.. It feels like a slipping clutch or something.
Any thoughts?
:(

Re: Broken driveline?

Sun Jun 29, 2014 7:33 pm

I think you are ok :D

Re: Broken driveline?

Sun Jun 29, 2014 7:45 pm

Pickerincal wrote:I can hold either final/hub still and with it in gear and still turn the drive shaft by hand, sounds like something giving way or dragging in the torque tube/transmission when I do this.
Brake band dragging on drum?

Re: Broken driveline?

Sun Jun 29, 2014 8:42 pm

No.. They are not hook up and are pretty loose. The fact that one turns and the other doesn't is what worries me..

Re: Broken driveline?

Sun Jun 29, 2014 10:41 pm

If you hold the one turning, the other should start turning. You are seeing normal differential action, but something is a little tighter or dragging on the side NOT turning.

Re: Broken driveline?

Mon Jun 30, 2014 1:55 am

John *.?-!.* cub owner wrote:If you hold the one turning, the other should start turning. You are seeing normal differential action, but something is a little tighter or dragging on the side NOT turning.


Ok.. It is possible a brake band is dragging but.. not much if any. Even so.. if your turning the drive shaft, at least one of the hubs should turn or you should not be able to turn the drive shaft. Correct? I just doesn't seem right to me. :(

Re: Broken driveline?

Mon Jun 30, 2014 5:10 am

If you turn the driveshaft with transmission in gear, at least one final will turn. IF you then stop the final that is turning (with a helper or a brake), the other one will turn. That is normal for a cub differential.

Re: Broken driveline?

Mon Jun 30, 2014 9:44 am

Yes, sounds normal. Technically, 2wd machines are really only 1wd, and 4wd machines are only 2wd. If you hold the drive shaft in place, with both wheels off the ground, then turn one wheel forward the other wheel will run backwards.

I know this has been posted before, but it's jsut a great explanation of how differentials work:

http://www.youtube.com/watch?v=yYAw79386WI

Re: Broken driveline?

Mon Jun 30, 2014 10:51 am

[quote="gitractorman"]Yes, sounds normal. Technically, 2wd machines are really only 1wd, and 4wd machines are only 2wd. If you hold the drive shaft in place, with both wheels off the ground, then turn one wheel forward the other wheel will run backwards.

I know this has been posted before, but it's jsut a great explanation of how differentials work:

Nice post.. Explains a lot. I'm going to have someone help me and run it through a few tests. I'm still a little skeptical but I could see there is probably nothing to worry about :D

Very nice video.. If only the makers of it could see the company they worked for now. Thank you for the posts :D

Re: Broken driveline?

Mon Jun 30, 2014 12:17 pm

The differential will "choose" whichever wheel is easier to turn. In your case there is probably a bit more drag on the driveline to the left wheel than the right, making the right easier to turn. That is why it always turns the right wheel and not the left.

There are no clutches inside the transmission. It's all hard gears and shafts so there is nothing to "slip." Either it works, or you have a broken gear.

Re: Broken driveline?

Mon Jun 30, 2014 1:41 pm

Pickerincal wrote:........ if your turning the drive shaft, at least one of the hubs should turn or you should not be able to turn the drive shaft. Correct? I just doesn't seem right to me. :(
You are correct, if it is in gear and you turn the drive shaft, one or the other or both wheels should turn. If you block both wheels are lock the brakes on both wheels you should NOT be able to turn the drive shaft.