129 that won't go into forward or reverse
 

I have a restored '71 129. Yesterdy, as I was going down the hill in our yard, my shorts caught on the drive release lever and pulled it up while the tractor was in motion. It will now not go forward or reverse. I took the cover off and the c-plate attached to the release lever had sheared off. I took the release valves out thinking that maybe they were stuck open, but they are working correctly. Anyone have any suggestions? I am worried that I damaged the hydrostatic pump because I was moving when the lever was pulled up.

Have you tried jacking it up and running it to see if you can get the tires to turn. I read someone else did a fluid change and the were air bound. then jacked it up and it slowly blead it self as it went into rev and fwd. Maybe try swaping the valves?

Check the spirol pins in the driveshaft before you do too much else.

Thanks for all the suggestions. Matt G. was right on, although I checked the other suggestions. The shear pin that connects the engine plate to the driveshaft had sheared off (as it was designed). Now I just have to find a replacement pin and get the old one out, as it is fairly rusted in the hole. If anyone had any suggestions on either score it would be appreciated (such as a part # for the shear pin). Thanks to all who replied and helped me find the problem!

Yup, just like the guys said, if you're talking about the front pin, I just bought one the other day, the part number in my books is IH-19837-R1 just like Wild Bill said, but the part number on my ticket is IH-19837-R2 (don't know what the difference could be) and the price was $4.83 plus tax.

Use the IH hardened steel dowel pin (19837 R1) and not a scroll pin in the drive shaft up front or you will continue to have issues. Be sure the dowel pin drives in hard or it will fly out. I have had to tack weld the pin in before if the hole in the shaft is worn.

If you have multiple tractors, it's much cheaper to buy the spirol pins from mcmaster-carr...They're like $10 for a package of 25. Search for 1.5" x 0.25" heavy-duty coiled spring pins.

I found a local CC dealer who had the pin in stock. I got my tractor fixed this afternoon. Thanks for all your help.