Mowing TC35DA Weak PTO

[DOtt]

I was out mowing grass today with a 72" rear finish mower and I think I have a problem. This is only the second time I've gotten to use the mower and the tractor's PTO as I purchased both last fall. The first time mowing I noticed that the mower would slow down but the engine did not. My first thought was the belt on the mower is slipping as it is a used mower. I slowed my speed and finished mowing without much trouble. As I was mowing deeper grass today I decided to pay more attention to what was happening at the mower and noticed that the PTO shaft was slowing with the mower but the engine is not. The PTO never stalled completely. I am relatively new to tractor ownership but it seems to me that if I put enough load on the PTO to slow it down I should be bogging the engine. And the little bit of grass I was cutting should have been easy to handle.

I've done a little looking around and I've read about some tractors having adjustments for the PTO but they all seemed to be for gear drive tractors and mine is a hydrostatic. I don't completely understand all the inner workings of the PTO in a hydrostatic transmission but I would guess that my problem will most likely require spending a lot of money, time, or both to replace the worn components. What could be going bad? Is there any adjustments that I am unaware of?

Any and all thoughts would be greatly appreciated.
Thanks in advance.

 

[Btown]

I only have gear tractors, so not familiar with hydros. Do you have a slip clutch on the mower or a shear pin?

 

[DOtt]

There is a bolt through the input shaft of the mower gear box. Not sure if it’s an actual shear pin or just a regular bolt. As I'm mowing (with some stretching and contorting) I can visually see the PTO shaft between the tractor and mower slowing down. If the engine is not slowing that must mean there is some slippage internal to the tractor. If I drive too fast it will slow to the point where the mower doesn't cut.

I've done some studying of parts diagrams on partspring and there is a clutch on the upper PTO drive shaft assembly. I'm wondering if this might be the culprit.

Can anyone explain to me how the PTO works in an HST? Is it hydraulically driven, direct shaft driven off the engine, etc.? That might help me diagnose what could be going bad.

 

[Spicer]

The pto on your tractor is engaged by a hydraulic operated clutch inside of the transmission.

Here are a few links.

PTO 1

PTO 2

The above link has linked images that show the internal workings of your pto.

Mike

 

[DOtt]

Thanks for the info Mike. The thread you provided explained the exact problems I'm having. Unfortunately the repair cost is gonna hurt.

 

[mac1520]

I was out mowing grass today with a 72" rear finish mower and I think I have a problem. This is only the second time I've gotten to use the mower and the tractor's PTO as I purchased both last fall. The first time mowing I noticed that the mower would slow down but the engine did not. My first thought was the belt on the mower is slipping as it is a used mower. I slowed my speed and finished mowing without much trouble. As I was mowing deeper grass today I decided to pay more attention to what was happening at the mower and noticed that the PTO shaft was slowing with the mower but the engine is not. The PTO never stalled completely. I am relatively new to tractor ownership but it seems to me that if I put enough load on the PTO to slow it down I should be bogging the engine. And the little bit of grass I was cutting should have been easy to handle.

I've done a little looking around and I've read about some tractors having adjustments for the PTO but they all seemed to be for gear drive tractors and mine is a hydrostatic. I don't completely understand all the inner workings of the PTO in a hydrostatic transmission but I would guess that my problem will most likely require spending a lot of money, time, or both to replace the worn components. What could be going bad? Is there any adjustments that I am unaware of?

Any and all thoughts would be greatly appreciated.
Thanks in advance.

DOtt: I have a TC-34DA with the same exact issue... It's only got 700 hrs on it and changed all the Hyd fluid and filters last week. What was the final fix?

 

[DOtt]

DOtt: I have a TC-34DA with the same exact issue... It's only got 700 hrs on it and changed all the Hyd fluid and filters last week. What was the final fix?

Double no triple check all your belts and pulleys on the mower. I'm embarrassed to say but my ultimate issues was in the mower belt tension. Even though it sure looked like my PTO shaft was slowing down. I don't know if the TC34 is any different than the TC35 but here is what I found researching the issue on my tractor.

Assuming everything on your mower is working properly there are a few things it could be. As I understand it the PTO is driven directly off the main shaft of the transmission by a clutch. That clutch is hydraulically operated by a valve assembly under your seat. I would start by inspecting an checking that valve assembly first as it is more easy to get at than the clutch itself. Make sure it isn't leaking and that the valve is being fully engaged when the lever is moved. If the valve doesn't fully open it will partially engage the clutch causing the clutch to slip and wear over time. The other thing that might be worth checking is hydraulic pressure in your system at the valve. If your hydraulic pressure is low the clutch might not be fully engaging. The next thing to look at would be the clutch itself. The clutch is buried in the heart of the transmission which is a more involved task to check.

I'm not an expert on this matter as I ended up not needing to dive into the tractor's inner workings to fix my issue. Again I'll say its worth your time to really go over the mower and make sure everything is working properly there first. If you have the option try hooking up to another PTO implement to test your tractor. Something direct drive would be best like a brush hog or a tiller.

 

[Ford850]

Worn or loose belts, or an improperly adjusted slip clutch on the mower are the most common causes for this. Plus they are the easiest to remedy. :thumbsup::thumbsup:

 

[mac1520]

Gents,

You both nailed it! My belt was loose.... Tightened and now she works like a champ. Thx.