GC2600 whining gone, then came back

   / GC2600 whining gone, then came back #1  

Dinico

Member
Joined
Jun 6, 2025
Messages
29
Tractor
Massey Ferguson GC2600
Long story short.

Tractor 650 hours. I bought with 400 hours. Maintained, scheduled maintenance since I owned it, garage kept, only repairs: new starter, two hydro lines on FEL.

My tractor has a constant whine. I determined it resonates from the steel hydro line that connects from the transmission to the PTO engage lever.

Doing other maintenance, decide to replace hydro filter with OEM filter even though doesn't need changed for another 150 hour. Suction filter was clean, cut open hydro filter and it was clean.

At start up, the whining was gone completely gone. Tractor ran, mowed, and sounded great. Reverse was even quicker and stronger. Ran better then ever. Daughter mows more than me and agreed.

Next day, on start-up, the whine is back. Like it never left, or I was driving someone else's tractor the night before. Night and day difference. Then I find that the hydraulic fluid now becomes foam when using MMmower.

Foam settles out in eyeglass after a few minutes.

ORings on suction filter looked good, not seeing any leaks.

Any advice?
 
   / GC2600 whining gone, then came back #2  
Just throwing some ideas into this. Did you notice any foaming of the oil at the beginning of all this or just since the noise went away and came back? Do you notice oil foaming if you don't use the mower? Is the oil level overfull?
 
   / GC2600 whining gone, then came back
  • Thread Starter
#3  
Never had any foaming issues prior.

1st time I've ever seen foaming was after the noise went away then came back.

Only foams when using the mower. I've taken the deck off checked for any leaks. Slightly tightened the suction filter and hydro filter. There was one drop of fresh oil on the hydro filter even though it was hand tight plus a half turn. Put deck back on, still foamy. Suction filter o-rings were properly aligned.

Disconnected the FEL lines and reconnected.

Oil level is slightly above halfway sitting in garage with FEL and 3pt down.

I'm at a loss. Can the hydro filter cause aeration?
 
   / GC2600 whining gone, then came back #4  
Long story short.

Tractor 650 hours. I bought with 400 hours. Maintained, scheduled maintenance since I owned it, garage kept, only repairs: new starter, two hydro lines on FEL.

My tractor has a constant whine. I determined it resonates from the steel hydro line that connects from the transmission to the PTO engage lever.

Doing other maintenance, decide to replace hydro filter with OEM filter even though doesn't need changed for another 150 hour. Suction filter was clean, cut open hydro filter and it was clean.

At start up, the whining was gone completely gone. Tractor ran, mowed, and sounded great. Reverse was even quicker and stronger. Ran better then ever. Daughter mows more than me and agreed.

Next day, on start-up, the whine is back. Like it never left, or I was driving someone else's tractor the night before. Night and day difference. Then I find that the hydraulic fluid now becomes foam when using MMmower.

Foam settles out in eyeglass after a few minutes.

ORings on suction filter looked good, not seeing any leaks.

Any advice?
Just throwing out a weird idea to see if it sticks: perhaps it has something to do with the PTO clutch; perhaps it is leaking. The PTO clutch is a series of wet plates that are engaged hydraulically.

In this screen print from the later service manual, the clutch pack is just to the left (forward) of the arrows from the 8 balloon. Those arrows are pointing to two O-rings that run on the shaft. Further aft, behind the gear and the bearing are two more O-rings (balloon 2). Hydraulic oil is injected through the passageway by balloon 1 into the hollow shaft between the aft O-rings, through the shaft, and exits the shaft between the forward O-rings.

Massey Ferguson GC PTO clutch pack & seals 1.jpg

Two more screen prints from the later parts manual. The PTO clutch pack is #45, the forward O-rings are #46, the shaft is #41, and the aft O-rings are #42.

Massey Ferguson GC PTO clutch pack & seals 2.jpgMassey Ferguson GC PTO clutch pack & seals 3.jpg


Try "pseudo-mowing": driving it around with the mower raised and the PTO not engaged and see if it still whines and foams.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#5  
Just throwing out a weird idea to see if it sticks: perhaps it has something to do with the PTO clutch; perhaps it is leaking. The PTO clutch is a series of wet plates that are engaged hydraulically.

In this screen print from the later service manual, the clutch pack is just to the left (forward) of the arrows from the 8 balloon. Those arrows are pointing to two O-rings that run on the shaft. Further aft, behind the gear and the bearing are two more O-rings (balloon 2). Hydraulic oil is injected through the passageway by balloon 1 into the hollow shaft between the aft O-rings, through the shaft, and exits the shaft between the forward O-rings.

View attachment 3595347

Two more screen prints from the later parts manual. The PTO clutch pack is #45, the forward O-rings are #46, the shaft is #41, and the aft O-rings are #42.

View attachment 3595348View attachment 3595349


Try "pseudo-mowing": driving it around with the mower raised and the PTO not engaged and see if it still whines and foams.
Hope it's not the PTO clutch. That is above my pay grade.

I did some "pseudo-mowing" as you calles it. Moved some bucket loads of compost to the garden, mower raised, and PTO not engaged. Still whines, but did not foam.
 
   / GC2600 whining gone, then came back #6  
foaming could be from deck vibration I suppose.
I have a whine with deck engaged, I have cap on tractor and it amplifies the noise. noise is mostly from deck itself, airflow/gear noise/etc.
I don't have foaming though.
there is ALWAYS a little hydro noise even on brand new GC tractors, thats normal.
run it until it breaks. you'll drive yourself insane chasing noises.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#7  
Good morning all,

I'm thinking the best course of action is to retrace or redo what caused the hydraulic fluid foaming. It wasn't foaming before I changed the filter. New one is AGCO filter 4265229M92 Made in Japan. That shouldnt be the issue.

The O-rings on the suction filter are properly seated. If I tighten it any more, it will break. Suction tube hose- I did tighten the clamps a turn for good measure, but that was after the foaming started.

Cold fluid level was slightly above the middle sitting in level garage with FEL down and 3pt down.

That leaves the obvious. The fluid. I am using the NAPA Starfire Premium HTF. Says it's M1145, Permatran III and 821 XL, anti-wear, foam suppression, VI is 141, GL-4, Group II Base oil. Same brand, I was using along with a NAPA cross-refernced filter.

So my plan:
1.Drain the fluid that's in it. It's junk.
2. Use the oil that was in it before the change to kind of flush out what junk oil remains. (I had drained it into a clean pan, and put into a clean bucket. Nothing was wrong with the oil when I changed it. I had read that an OEM filter may stop my whining. Which it did for about 2 hours. Then next day whine was back along with foam.)
3. I will cycle it and drain.
4. I'll do this and report back if it is foaming.


Questions are: Will this procedure help to get most of the foamy oil out so I don't contaminate new oil? Do I need to do this multiple times to get all junk oil out?

Should I replace the brand new filter I just put on with a new one?

And what fluid? The closest dealer to get Permatran 821 XL is 70 miles one way. Is there something better? At this point, I want what is best. Kinda answered my own question on that one. 🤷

Thanks for any suggestions or comments.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#8  
foaming could be from deck vibration I suppose.
I have a whine with deck engaged, I have cap on tractor and it amplifies the noise. noise is mostly from deck itself, airflow/gear noise/etc.
I don't have foaming though.
there is ALWAYS a little hydro noise even on brand new GC tractors, thats normal.
run it until it breaks. you'll drive yourself insane chasing noises.
You are right about the chasing noises. Would be glad for just the whine and no foam at this point.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#9  
OK. I drained the foamy oil. Emptied out filter. Put back in the oil that was previously in it. Let it warm up a but before cycling. Then cycled the FEL and 3pt lift.

No foam in eyeglass while it's idling.

Should I put the deck back on to cycle the PTO?
Doing it without a load seems not good.

And after cycling the FEL and 3pt, they are both down now, the eyeglass barely shows any fluid.

Top it off?
 
   / GC2600 whining gone, then came back #10  
yes to both, top off then test with deck on. fwiw I use little red dye to easily see in glass and trace leaks.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#11  
Oil level went back to middle after starting it and curling the bucket. Both FEL and 3 pt were down.

Oil was clear driving, using FEL, and 3 pt lift.

I put the deck on to cycle it. Engaged PTO for about 15 seconds. Checked fluid. All cloudy with heavy foaming layer at top. Engaged another 15 seconds and it was all foam.

Drive back into garage. Lowered both FEL and 3pt while it was running at idle. Fluid cleared in about 1 minute.

Was at middle level.

I turned off the tractor and watched the fluid level drop to below the eyeglass.

What's up with this? Do I have a vacuum somewhere?
 
   / GC2600 whining gone, then came back
  • Thread Starter
#12  
yes to both, top off then test with deck on. fwiw I use little red dye to easily see in glass and trace leaks.
Good call on adding some die. Definitely going to get some. I did test with deck. Still foam.

My most recent post explains the fluid level.

It's at middle with FEL and 3pt down. I shut it off. Then the fluid in the glass drops below the sight. I've never seen this happen before.

I've never read about it happening either.🤷
 
   / GC2600 whining gone, then came back #13  
Never had any foaming issues prior.

1st time I've ever seen foaming was after the noise went away then came back.

Only foams when using the mower. I've taken the deck off checked for any leaks. Slightly tightened the suction filter and hydro filter. There was one drop of fresh oil on the hydro filter even though it was hand tight plus a half turn. Put deck back on, still foamy. Suction filter o-rings were properly aligned.

Disconnected the FEL lines and reconnected.

Oil level is slightly above halfway sitting in garage with FEL and 3pt down.

I'm at a loss. Can the hydro filter cause aeration?
I can see the filter gasket seal having some effect on air ingestion, but the PTO use (or not) should have no bearing on that. This is a belly mower using mid mount PTO? I can see the additional gears turning having some bearing on this depending on oil level, but it shouldn't cause any problem. No hose clamps on any suction line connections? I always tighten them with a 1/4" drive ratchet now since I can't get them tight enough with a screwdriver or nut driver.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#14  
I can see the filter gasket seal having some effect on air ingestion, but the PTO use (or not) should have no bearing on that. This is a belly mower using mid mount PTO? I can see the additional gears turning having some bearing on this depending on oil level, but it shouldn't cause any problem. No hose clamps on any suction line connections? I always tighten them with a 1/4" drive ratchet now since I can't get them tight enough with a screwdriver or nut driver.
Yes, belly mower using mid mount PTO. 2 hose clamps on the suction line. I had to use a ratchet myself to tighten them up.

Is it possible for the hydraulic filter itself to be faulty?
 
   / GC2600 whining gone, then came back #15  
Possible? I guess most anything is possible, but that wouldn't explain why operating a mid PTO would make a difference. What happens if you run just the rear PTO?
 
   / GC2600 whining gone, then came back #16  
Possible? I guess most anything is possible, but that wouldn't explain why operating a mid PTO would make a difference. What happens if you run just the rear PTO?
I was just gonna ask if there was a rear pto implement (snowblower, tiller,etc) that could be hooked up to isolate if only front 2k rpm output or both outputs affected.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#17  
I was just gonna ask if there was a rear pto implement (snowblower, tiller,etc) that could be hooked up to isolate if only front 2k rpm output or both outputs affected.
Possible? I guess most anything is possible, but that wouldn't explain why operating a mid PTO would make a difference. What happens if you run just the rear PTO?
Haven't thought of that. Your both right as it could isolate the issue. Haven't had the tiller on this year. Honestly the whining sound always made me anxious when I ran the tiller. I will hook it up and give it a spin.
 
   / GC2600 whining gone, then came back #18  
is it possible you left old seal on when changing filters?

when testing with tiller do what you can to make sure pto shaft is straight from output to tiller to help negate any joint noise.
 
   / GC2600 whining gone, then came back
  • Thread Starter
#19  
Something doesnt seem right.

It's never done this before.
Tractor is at idle.
It's setting level with FEL and 3pt down.
Hydro level is at middle.
Turn off engine and level drops below glass.

I have released any residual on both. I actually disconnected all of the FEL quick connects.
When I start the engine, oil level immediately returns to middle.
Turn it off, drops back down. Where's the fluid going? Is there a pressure relief valve not opening?
is it possible you left old seal on when changing filters?

when testing with tiller do what you can to make sure pto shaft is straight from output to tiller to help negate any joint noise.
Didn't leave oil seal on. Already rechecked. I had cut open the old filter to check for if it was clogged.
 
   / GC2600 whining gone, then came back #20  
Is the foam from the PTO gears turning in the oil? If pump was cavitating it would be happening all the time and not just when PTO is engaged.

I know that running the PTO on both the BX1850 I used to have and 2400H I currently have heats the oil up more than just driving around without PTO engaged.
 

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