1872.... Shudder in reverse

[diesel_nut]

I have recently started to get a shudder in my 1872 when going in reverse. Any ideas?
It's like a strong vibration.

 

[diesel_nut]

OK now it shudders when I push the hydrostat lever(change speeds). Tranny going out?

 

[diesel_nut]

Should the shaft coming from the engine to the tranny (with the propellar blade cooler) be bent?
Is this why this tractor has vibrated so much since I've had it?
When spinning it does not turn true. It has an oblong path.
And now I decided to change out the sprak plugs since I was in there and the left cylinder's threads are buggered up to the point the plug won't tighten. So that is why it mysteriously fell out the other week. But it tightened right up when it when in.
Previous owner or shop cross-threaded the plug.
Great.

 

[Bob_Bainbridge]

The drive shaft should not be bent and should have very little noticable runout when rotating. They make repair kits for stripped plug threads. They are called heli-coil (or something like that) and thread into the old hole to form new threads. If the plug won't stay tight you will have to repair the threads.

Bob B.

 

[diesel_nut]

The shudder was from loose hydro unit mounting bolts. One was even............... MISSING!
Yup that is a heli-coil. If I can't find a used head or if a replacement is too expensive I will try the heli-coil.