TD33DA transmission noise

[paul dyar]

I've noticed a knocking noise in the transmission area when in idle. If I depress the clutch it stops, that makes sense. But it also goes away when I increase the RPM. Everything is working fine, hydraulic level is ok. May have been doing it before and not noticed it. Is this a sign of a major problem?
Thanks in advance,
Paul

 

[jinman]

Paul, what you are hearing may be a ball-check valve on the top of your HST filter. That valve is designed to relieve pressure when the tractor and HST fluid is cold and has high viscosity. When you idle, sometimes the pressure will surge and cause a click-clack sound and the ball checkvalve seats and unseats. The next time you hear the noise, listen closely to the HST filter area to see if that's where the sound is coming from. The reason it goes away when you press the clutch, is that you stop the input to the HST transmission and its charge pump so that no fluid at all is flowing. When you increase the rpm, there is no surge of fluid and the checkvalve is held in position so that it doesn't click.

I hope that's the source of your noise and you can operate your tractor without worry.

 

[art]

Straight cut transmission gears will make noise when a low idle speed is used and will also stop under all the conditions that you have stated.