Cub Cadet 3225 will not pull a grade

[bassnailer]

Originally Posted by ejl6658

Your transmission is a BDU-21L-500. Attached is the link for the BDU service and repair manual.

https://www.hydro-gear.com/service-and-repair-manuals/

There is also a pressure testing procedure in the 3000 series service manual.

Major update! I went through the troubleshooting diagram found in the manual ejl6658 linked. When I got to the bypass valve check, I went to move my tractor underneath the hoist so I could pick it up and check the linkage. First, the tractor moved without disconnecting the transmission. It did not just roll freely, but I was able to move it without too much trouble and, as I recall, I've never been able to move it at all without disconnecting the transmission. I hoisted it up so I could get under it, and saw that the sheet metal tab that pushes on the bypass valve was dented up quite a bit and pushing on the valve. I removed the disconnect rod and the sheet metal tab so that I could inspect the bypass valve. I worked it in and out a couple of times until it moved freely.

After inspecting the bypass valve, I attempted to mow the grass as a test run. The tractor is now pulling moderate grades just fine, and only stalls on the very steepest grades in my yard. All in all, I would say it's about a 75% improvement from where it was. I checked the fluid after mowing and pulling grades, and it was no longer frothy.

So, at this point, I think that I must have run over a limb which pushed up against the disconnect tab and bent it to where it was constantly pressing on the bypass valve. The partially depressed bypass valve was likely doing just what it's supposed to, and let pressure bypass whenever I encountered a grade not allowing full power to the drive valves. I am also guessing this constant bypassing is what caused the fluid to get all frothed up as well.

With it still being down on power from what I recall (it has been about two years since it ran correctly) I am guessing I either did some permanent damage to the transmission by running it partially disengaged for so long, or there is still just some air in the system that needs to work its way out. Even at what I am guessing is 75% power though, I have adequate power to mow and the tractor will now do everything I need it to.

Thank you to everyone who contributed to help me solve this problem, and thank you ejl6658 for sharing the link to the transmission manual. That manual provided me the knowledge I needed about the system to really find out what was going on!

[ejl6658]

Glad you got it fixed without having to do a major tear down.

[curtm]

where's the screen filter,pic would be nice, i have a 3185

[Yardman]

Where can I see/find the pedal bushings you referenced. I also have the situation where reverse is very slow but when pulling up on the forward pedal reverse is much faster. Appears that I need to replace the bushings but didn't see part numbers on pedal diagrams. Thanks