Allis Chalmers C Tractor stopped moving when mowin

Hello.
I have a 1948 C that I use an underbelly mower with. Last summer when mowing it stopped moving and the pto stopped while remaining running. Starts right up but does not move and pto does not engage, only tried 1x as I do not want to break anything other than what is possibly already broken. Have not split tractor yet, been putting off.
Looking through clutch view hole clutch engages and disengaged as best one can see.
IF I put in gear when not running gear engages and cannot push tractor by hand. Moves in neutral. Trying to give as much information as possible...
Any thoughts what caused this and what I should be looking for?
I have seen a post about a cotter pin in the clutch shaft that breaks, but that post indicated would not cause tractor issues when together.
Any help is greatly appreciated.

Edited by Johnniewb1 - 14 Apr 2024 at 12:49pm

If the tractor will not move... AND you have no PTO drive... then you have a problem with the drive shaft out of the main clutch to the transmission. That is the only thing that effects BOTH...When the shaft gets to the transmission, it GEAR DRIVES two different shafts for the trans and pto..

Thank you. Did these steps without tractor running.
I engaged the pto, was able to turn using pto side pulley that runs mower deck. Mower deck blades moved as they should and rear pto also spun. Through smaller port window above nut that holds wishbone on I could also see the flywheel unit spin as well.
Engaged tractor into 3rd gear and was able to move tractor forward using pto. Does this provide any additional help in helping me to figure this out? I appreciate the help thus far.

Edited by Johnniewb1 - 14 Apr 2024 at 12:53pm

With pto engaged fan blade spins. So thinking I am thankful for that!
Have not restarted tractor since this happened last year.
But tractor did immediately fire back up from starter last year when I was questioning what had just happened after I turned it off when it stopped moving and mowing.
So is this pointing towards a clutch issue? Clutch had been replaced about 5 years ago at this point I am guessing.
Again I am very appreciative of the help as I would like to get this tractor back up and running.

I did check clutch fingers last year when I gave up, all springs in place and it looks good.....

Where is the coupling your are referring to? In front if the gear box or ? I do have 3 different manuals that are helpful, but....

I also have thought about restarting and seeing what happens, but didn't want to create any additional issues

By coupler are you referring to the end of the drive/clutch shaft at the rear connecting to the 'gear' box area? Sorry for poor terminology.

steve(ill) wrote: Yes... the transmission shaft sticks out 2-3 inches infront of the case.... the "DRIVE SHAFT" sticks into the clutch and extends back ( about 3 ft ?) and then connects to the transmission shaft... Couple different designs over the years.. Some had a retaining cotter pin as you said, so when you pull the motor out the shaft pulls out of the clutch and stays inside the torque tube attached to the transmission.. some dont have the cotter pin. To attache the drive shaft to the transmission shaft, i have seen splined sleeve retained by a cotter... have also seen a cheap typ u-joint used.... Seems like there is "MORE STUFF" at the clutch end to go wrong than at the rear of the drive shaft ??

You can see the cotter pin by removing the steering wheel brace/ pipe. The b we had at work was just the smooth drive shaft, no spline. The one guy would always pop the clutch and shear the pin. I’ve tried cotter pins, split roll pins the finally used a grade 8 bolt and nut. You can change them from that hole if you’re patient. Lining the holes is the worst part.

I have never seen a setup where the cotter pin was taking the load.. All i have seen the cotter doing is keeping the shaft connected to the trans, when you pull the engine out the front... I dont see how a smooth shaft with a cotter pin would drive.. You would be relying on the pin to take 20 HP.. that wont work.

Steve, you think clutch then or ...?

steve(ill) wrote: I have never seen a setup where the cotter pin was taking the load.. All i have seen the cotter doing is keeping the shaft connected to the trans, when you pull the engine out the front... I dont see how a smooth shaft with a cotter pin would drive.. You would be relying on the pin to take 20 HP.. that wont work.

Steve. The trans shaft is splined but the drive shaft looked to be homemade repair. It had a universal but a pipe was welded to it then pinned to the trans shaft

Mine is original, no repairs as far as I know!

(I guess if you can align the holes and pin  thru the pipe tower hole, that would be a quick fix.)-----jphnnie.. i dont think this is your problem... it ws JOHNS probelm.... but i dont think a smooth sleeve over the spline shaft is a good design.. And you will not be able to split between the trans and torque tube... if you do, the shaft will pull out with the clutch and torque tube... then you will need to pull the engine to get the shaft back into the clutch after installing the shaft onto the trans... ??????

Edited by steve(ill) - 14 Apr 2024 at 6:30pm

YEP... i just figured out that john and johnnie are two different tractors... I think your on the right track now... I just updated my OLD POSTS..

Edited by steve(ill) - 14 Apr 2024 at 6:35pm

Had to buy new battery, pushed outside as is stored in my basement. Fired up first try, engine is great!
Pushed in clutch put in reverse and backed up about 30 feet. Pushed in clutch, put in 1st moved about 5 feet and then it stopped. Initial slight noise from under steering column and through bell housing of clutch. Noise is like a vibration, hard to describe. Would not re-engage to move. Pto would engage at low rpm. Noise does not appear present in neutral. Pushed back inside
will be splitting or probably into 3 pieces in the next few weeks. Any additional thoughts?