PTO bogs down while mowing

[mac1520]

Got a bit of a problem that started on my New Holland TC34DA (HST) earlier this summer. With the land pride 72 inch mower going on the rear PTO, if I hit thick grass, the PTO BOGS way down. Engine RPM says steady, but you can hear the mower just slow way down. Every now and then the Rear PTO shift knob pops out of gear. Goes back in with no problem, but happens from time to time... Changed all Hyd fluid & Filters... Still does it. I have 760 hrs on it and everything else works fine.

Appreciate any help.

 

[Soundguy]

No engine rpm change, but pto rpm change? = very bad. They are ratio locked.

I'm not up on that new machine, but if it is ind pto, that clutch is slipping either from gross overload ( not likely if engine doesn't bog ) or perhaps if hyd, the clutch pack is not being pressurized.

 

[kthompson]

Are you sure the mower is really dropping rpms and just the heavier grass load has change the sound of the air is able to make around the blades? Is this a rough cut or finish mower? If finish mower sure the belt is not slipping? If rough cut does it have a clutch on the pto shaft? If so could it be slipping? kt

 

[mac1520]

No engine rpm change, but pto rpm change? = very bad. They are ratio locked.

I'm not up on that new machine, but if it is ind pto, that clutch is slipping either from gross overload ( not likely if engine doesn't bog ) or perhaps if hyd, the clutch pack is not being pressurized.

Yea... Not happy with the idea of replacing the clutch, but wondering if the PTO Clutch valve is not doing its job correctly causing the clutch to slip?

 

[jeff9366]

On my Land Pride R/C the PTO slip clutch on the R/C is adjusted using a socket to increase or decrease spring pressure.

When was the last time you sharpened the blades on your R/C? If blades are dull, the increased pressure of resistance and clippings load may be making the slip clutch slip, which it is supposd to do.

 

[mac1520]

Are you sure the mower is really dropping rpms and just the heavier grass load has change the sound of the air is able to make around the blades? Is this a rough cut or finish mower? If finish mower sure the belt is not slipping? If rough cut does it have a clutch on the pto shaft? If so could it be slipping? kt

It's a finish mower and positive it's definitely the mower & PTO slowing down. The grass is cut each week, so the mower should be able to cut it with minimal issue. RPM stays rock solid, you don't see the tach needle move at off the 540 at all. Looked at belt and it's good, regreased all the fittings, blades spin nice and easy by hand. All great questions...thx

 

[oldnslo]

Mac1520
I looked at the parts breakdown for this model and didn't see a reference to a PTO clutch. Do you have to depress the clutch and then engage the PTO on this model. When you press in the clutch does the tractor also stop moving?

If yes I would adjust or check the freeplay on your clutch.

 

[mac1520]

On my Land Pride R/C the PTO slip clutch on the R/C is adjusted using a socket to increase or decrease spring pressure.

When was the last time you sharpened the blades on your R/C? If blades are dull, the increased pressure of resistance and clippings load may be making the slip clutch slip, which it is supposd to do.

Had my neighbor come look at the deck, but since it's a finish mower, there was no adjustable clutch. I had the same thought initially about the blades, so sharpened them all two weeks ago, figured since it was a HST, I'd try new Hyd oil and filters (it was old - 450 hrs since last time).. No change.

 

[mac1520]

Mac1520
I looked at the parts breakdown for this model and didn't see a reference to a PTO clutch. Do you have to depress the clutch and then engage the PTO on this model. When you press in the clutch does the tractor also stop moving?

If yes I would adjust or check the freeplay on your clutch.

Interesting... I saw a similar problem on a TC35, and was thinking it had one, but there is no access panel below the drivers seat, so I ordered the repair manual section that covers PTO & Hydraulics. I do have to push the clutch to engage the PTO and yes, the tractor stops moving with the clutch engaged. I will definitely check for the free play adjustment and report back. Thank you!

 

[stuckmotor]

I'm not up on these tractors. If this was my MF with a two stage clutch, I'd suspect the PTO clutch was out of adjustment. The PTO shift knob popping out adds another dimension to the problem. Hopefully it's an inexpensive symptom of something being out of adjustment.

 

[SPYDERLK]

Got a bit of a problem that started on my New Holland TC34DA (HST) earlier this summer. With the land pride 72 inch mower going on the rear PTO, if I hit thick grass, the PTO BOGS way down. Engine RPM says steady, but you can hear the mower just slow way down. Every now and then the Rear PTO shift knob pops out of gear. Goes back in with no problem, but happens from time to time... Changed all Hyd fluid & Filters... Still does it. I have 760 hrs on it and everything else works fine.

Appreciate any help.

It's a finish mower and positive it's definitely the mower & PTO slowing down. The grass is cut each week, so the mower should be able to cut it with minimal issue. RPM stays rock solid, you don't see the tach needle move at off the 540 at all. Looked at belt and it's good, regreased all the fittings, blades spin nice and easy by hand. All great questions...thx

Had my neighbor come look at the deck, but since it's a finish mower, there was no adjustable clutch. I had the same thought initially about the blades, so sharpened them all two weeks ago, figured since it was a HST, I'd try new Hyd oil and filters (it was old - 450 hrs since last time).. No change.

Your problem is tractor internal. Hopefully this V V V [external] adjustment will fix it.

Interesting... I saw a similar problem on a TC35, and was thinking it had one, but there is no access panel below the drivers seat, so I ordered the repair manual section that covers PTO & Hydraulics. I do have to push the clutch to engage the PTO and yes, the tractor stops moving with the clutch engaged. I will definitely check for the free play adjustment and report back. Thank you!

 

[Tx Jim]

Pto clutch appears to be hyd controlled. I would suggest to check hyd pressure on pto control valve. How long since hyd filter was changed & sump screen cleaned?

 

[mac1520]

I'm not up on these tractors. If this was my MF with a two stage clutch, I'd suspect the PTO clutch was out of adjustment. The PTO shift knob popping out adds another dimension to the problem. Hopefully it's an inexpensive symptom of something being out of adjustment.

Agreed... Trying to hopefully "Keep it Simple" for now... I've had the tractor since 300 hrs and realized this year the problem has really progressed. Last two mowing seasons just thought it was normal with thick grass. My simple thinking: Think the RPM not changing is the key... I would think it would drop a little with the heavier grass. This year we have had SOOOOOooo much rain and the grass just keeps coming... Normally this time of year it's brown and only have to mow every other week. Not complaining mind you, but I can hear it growing as I type this! Lol.. Checking the operators manual now to see how to adjust correctly... If not there, then repair manual will be here in a few days. Appreciate everyone's input. Hate going down the wrong rabbit-hole!!:laughing::laughing:

 

[mac1520]

Pto clutch appears to be hyd controlled. I would suggest to check hyd pressure on pto control valve. How long since hyd filter was changed & sump screen cleaned?

just changed both filters and 9 gallons Hyd fluid. The old fluid was pretty rough and I did not check the sump screen... I will check that also! Thanks.

 

[SPYDERLK]

Interesting... I saw a similar problem on a TC35, and was thinking it had one, but there is no access panel below the drivers seat, so I ordered the repair manual section that covers PTO & Hydraulics. I do have to push the clutch to engage the PTO and yes, the tractor stops moving with the clutch engaged. I will definitely check for the free play adjustment and report back. Thank you!

Pto clutch appears to be hyd controlled. I would suggest to check hyd pressure on pto control valve. How long since hyd filter was changed & sump screen cleaned?

These appear incompatible.

 

[mjonesnh]

Own the same model tractor. Looked in repair manual and saw nothing that would connect it with a hyd. pto. looks gear driven to me with a single stage clutch to engage and dis-engage. Looked for troubleshooting info but found nothing that would apply to your issue. Never had my bushhog slow down without rpm's dropping accordingly. Unless your clutch is slipping I dunno.

 

[STx]

I have a TC40, mine is a hydraulic clutch. I had a problem with aeration in my fluid and one of the symptoms was exactly what you're describing. Is there any air in your fluid? If so, it's likely your issue. Mine was getting aerated from a small crack in the supply line to the pump. They found the crack by pressurizing my fluid reservoir so that it would drip.

 

[motownbrowne]

I know nothing about the tc34, but I agree with SPYDERLK on this one. If you have to put in the clutch to start the PTO, it doesn't seem to be hydraulic. We are gonna need to sort that out before any other advice makes sense. If it's not a hydraulically activated clutch, you can forget about the whole hydraulic system. I do know that the PTO clutch on my tc29 is not hydraulic, but that may be completely different.

If it's not hydraulic, and it's not a two -stage clutch, and it does have enough power to mow, but seems to be slipping, it would seem to me that your primary clutch is slipping. It should be pretty easy to test that. Go push up against an unmovable object. Put the tractor in high range and put the clutch in. Depress the rocker pedal most or all of the way. It should stall your engine pretty easily, or maybe go into relief, but if it seems reluctant to bog the engine, your clutch may be slipping. Might be a simple adjustment to make. Might require a new clutch.

Whatever it is, it's probably better to figure it out before using it more.

 

[mac1520]

Own the same model tractor. Looked in repair manual and saw nothing that would connect it with a hyd. pto. looks gear driven to me with a single stage clutch to engage and dis-engage. Looked for troubleshooting info but found nothing that would apply to your issue. Never had my bushhog slow down without rpm's dropping accordingly. Unless your clutch is slipping I dunno.

Agree... Reading the owners manual and the only adjustment is for the free play on the single stage clutch. Hyd PTO is not a player for this model. I'm the second owner and don't think it's ever been adjusted, so I'll see how much it's out of whack and report back this evening.

 

[mac1520]

I know nothing about the tc34, but I agree with SPYDERLK on this one. If you have to put in the clutch to start the PTO, it doesn't seem to be hydraulic. We are gonna need to sort that out before any other advice makes sense. If it's not a hydraulically activated clutch, you can forget about the whole hydraulic system. I do know that the PTO clutch on my tc29 is not hydraulic, but that may be completely different.

If it's not hydraulic, and it's not a two -stage clutch, and it does have enough power to mow, but seems to be slipping, it would seem to me that your primary clutch is slipping. It should be pretty easy to test that. Go push up against an unmovable object. Put the tractor in high range and put the clutch in. Depress the rocker pedal most or all of the way. It should stall your engine pretty easily, or maybe go into relief, but if it seems reluctant to bog the engine, your clutch may be slipping. Might be a simple adjustment to make. Might require a new clutch.

Whatever it is, it's probably better to figure it out before using it more.

Think you guys are on the MARK! I'm doing errands right now, but when I get back I'll do all the above... Really believe the single stage clutch has too much free play... I'll let cha know what I find!