Cub Cadet 3225 will not pull a grade

[bassnailer]

Quick update. Since my last post, I noticed oil dripping from the supply line near the filter. I have drained the fluid, replaced the o-ring, and filled it back up with the synthetic blend Rotella. I also took the posted advice and marked the axles and wheel with paint to index the location of the splines relative to the wheels. I test drove the tractor and it is now pulling small grades, which is an improvement. I drove it around the yard for about a half hour pushing it as hard as I could up grades to allow it to repeat the problem (hydraulic squealing and shuddering while not being able to go up the grade). After doing this, I checked the paint marks and they were indexed exactly as they were when I began (see photo below of mark after test drive).



Because replacing the o-ring on the supply line significantly improved the hydraulic power, I am thinking that there may be more seals in the hydraulic pump which are allowing pressure to blow past. Does anyone perform a rebuild service for these hydro pumps? I found a used one from a board sponsor here for $500, but hate to buy a used one which will develop the same issues in a few years and would rather put the money towards having mine rebuilt if such a service is available.

[Billy-O]

Originally Posted by bassnailer

Quick update. Since my last post, I noticed oil dripping from the supply line near the filter. I have drained the fluid, replaced the o-ring, and filled it back up with the synthetic blend Rotella. I also took the posted advice and marked the axles and wheel with paint to index the location of the splines relative to the wheels. I test drove the tractor and it is now pulling small grades, which is an improvement. I drove it around the yard for about a half hour pushing it as hard as I could up grades to allow it to repeat the problem (hydraulic squealing and shuddering while not being able to go up the grade). After doing this, I checked the paint marks and they were indexed exactly as they were when I began (see photo below of mark after test drive).



Because replacing the o-ring on the supply line significantly improved the hydraulic power, I am thinking that there may be more seals in the hydraulic pump which are allowing pressure to blow past. Does anyone perform a rebuild service for these hydro pumps? I found a used one from a board sponsor here for $500, but hate to buy a used one which will develop the same issues in a few years and would rather put the money towards having mine rebuilt if such a service is available.

I would pull that cooler as recommended earlier if I were you. You might be surprised and would not need to spend that five bills....

[Oak]

I wonder if you have a cracked tube?


You can download the free manual here for doing some pressure tests.
https://www.mymowerparts.com/pdf/Cub...epair-Manuals/

Good luck and report back.

[ejl6658]

Have you tried replacing the bushings on your pedal linkages and tried adjusting them to see if it makes a difference?

[bassnailer]

Originally Posted by ejl6658

Have you tried replacing the bushings on your pedal linkages and tried adjusting them to see if it makes a difference?

Yes. I have replaced all the bushings and adjusted the travel pedals. The tractor moves great on level ground, forward and backward. It's just when I encounter a grade.

[bassnailer]

Originally Posted by Billy-O

I would pull that cooler as recommended earlier if I were you. You might be surprised and would not need to spend that five bills....

The problem existed before I added the cooler, and the cooler was an attempt to correct the problem. The problem doesn't exist when the tractor is cool and gets worse as I mow. Because the fluid was hot and frothy when the problem occurred, I was thinking the hydraulic fluid may be getting too hot. That's not the problem though, as I can lay my hand on the oil cooler when the problem is occurring and it only feels warm, not hot. Once I get it all sorted out, I will most likely ditch the cooler as it was more of a diagnostic tool than anything else.

[Billy-O]

Originally Posted by bassnailer

The problem existed before I added the cooler, and the cooler was an attempt to correct the problem. The problem doesn't exist when the tractor is cool and gets worse as I mow. Because the fluid was hot and frothy when the problem occurred, I was thinking the hydraulic fluid may be getting too hot. That's not the problem though, as I can lay my hand on the oil cooler when the problem is occurring and it only feels warm, not hot. Once I get it all sorted out, I will most likely ditch the cooler as it was more of a diagnostic tool than anything else.

That's your call to make. You might have made matters worse trying to rectify the problem by adding the cooler. Now that you replace a seal, you reported the tractor is doing better. Is pulling the cooler and return the hydraulic lines to the original set up that difficult?

[bassnailer]

Originally Posted by Billy-O

That's your call to make. You might have made matters worse trying to rectify the problem by adding the cooler. Now that you replace a seal, you reported the tractor is doing better. Is pulling the cooler and return the hydraulic lines to the original set up that difficult?

Fair point, it won't hurt anything to go ahead and remove it now. That way I can eliminate both overheating (because the cooler did not fix it) and the cooler itself as a potential source of air getting in the system.

[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.

[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.

Thank you, this is a great resource! I'll be testing the pressure this evening when I get home. I appreciate it.