Mowing MX6 Engagement Noise w/ 3520

[Thowle]

Hey Guys,

Got a used MX6 the other day -- it's a 2009, in decent/good shape. Checked the gear box, seemed dry so filled with new oil. Haven't flipped the cutter up to look under at the blades yet.

Last night when I got it, I engaged it around 2000 RPM with my John Deere 3520 tractor; it engaged fine, had some vibration until I got it up to speed, but mowed good. Couldn't hear anything weird from within the cab.

Today I stood outside the cab and engaged it around 1500 RPM and it made some weird noise.. almost a grinding noise for a few seconds until the tractor recouped from the RPM loss. It didn't sound like it was coming from the slip clutch or gearbox on the cutter; sounded like it was coming from the engine bay of the tractor.

Any ideas? Just because it's such a big cutter for the 3520? It doesn't do it once it's already turning; just that initial jump from no-movement, to engaged. If I feather the engagement with the PTO switch, it's doesn't do it. Engaging over 2000 RPM makes for a lot longer and louder noise... only did that once :thumbdown:

I'm assuming right now that it's normal since the cutter is at or over the high end for what this tractor is capable. Just don't want to tear anything up; or would like to figure out if anyone else has the same issue and what they do to lessen the strain upon initial engagement.

 

[murphy1244]

I engage mine at idle and then bump it up. You might be hitting it too hard.

 

[Thowle]

Tried idle. Makes noise and drops too many rpm, makes oil pressure alarm go off and about to stall.

 

[lostcreekranch]

It may be a bit too big for your 3520. Deere recommends the MX-5 for the 3520.

http://www.deere.com/wps/dcom/en_US...ity_tractor/3520_compact_utility_tractor.page

 

[mmurphydds]

The manual for the MX-6 discusses how to adjust the slip clutch after periods of non-use...I would certainly do this with a "new-to-you" used implement. The slip clutch should slip a little at engagement (solves the drastic RPM drop) and is more gentle on your driveline. Horsepower-wise, I think you're okay with the 3520, but again adjust the slip clutch so your engine doesn't lug under high load. If you don't have the manual, let me know and I can walk you through the process. Good luck, I have loved my MX-6, and used it very hard.

 

[Thowle]

Hey mark, is this the correct procedure?

http://manuals.deere.com/omview/OMW49746_19/?tM=

 

[Danscaper]

I read this all the time where people engage there implents at high rpm. Your supposed to do it at idle. ITs no differnet than hitting a stump with your blades. The people that do this are going to be in for some very costly repairs to the engine and pto's prematurely. just imagine all that shock your subjecting your equipment to while doing that. Its like going a 100 mph and then hitting a brick wall. Just saying, be careful with that expensive machine and engage pto at lowest idle which the manual states as well

 

[Thowle]

Okay... Slip clutch seems fine. Re-tightened it, still a lot of noise... Sounds like from under mower now... hmm, guess I need to flip it over.

 

[mmurphydds]

I looked at the online manual you referenced, and it has a section about disassembly, which seems like more than you need to check out its operation. I remember reading in some of my literature that you loosen the 6 bolts holding the clutch together, to the point that when you engage the PTO it slips like crazy for a few seconds, effectively burning off all the accumulated corrosion, rust and crud between the plates and giving you new, clean surfaces, to work with. After this few seconds of "burn-in" you shut it down and then re-tighten all the bolts equally, to the point where you get a momentary squeal when you engage the PTO. That way you get a clutch that, in fact, does slip if you hit something, and that stays clean because of the momentary slip each time it is engaged.

 

[mmurphydds]

Okay... Slip clutch seems fine. Re-tightened it, still a lot of noise... Sounds like from under mower now... hmm, guess I need to flip it over.

Every now and again, I used to get a nasty grinding noise coming from under my MX-6, and it was invariably due to the bolt holding the blade pan on having come loose. I would re-tighten it as best I could using a long pipe over my socket handle to give the requisite gazillion ft/lbs of torque...and then after hitting some big hunk of something later on, I would have to repeat the procedure.... I got tired of this, so I looked up the online parts manual and found that there are 3 variants of the attachment system for this pan, including a field install kit that included a weld-on collar around the bolt hold and an indexing insert and retaining spring to keep the bolt from backing out. 2 years later, all is still well and the problem seems solved. This might be your noise, and if so, I would recommend this solution.

On numerous threads in the past, people have ripped on the gearbox of the MX-6 as being a piece of crap, or unable to get parts for or whatever. So you might have to check that out, too. I have never had that issue, fortunately, although I am not nearly as tough on it now as when I was first developing my several miles of trails through my deer woods. Now it's just maintenance mowing and grinding up cornstalks in the spring from the previous year's food plots. Good luck!

 

[arlen4720]

When is your 5115M going to be delivered? That should spin the MX6

 

[murphy1244]

on the slip clutch you need to tighten it to take the force off

 

[Thowle]

Loosened all of the bolts on the slip-clutch, made a mark, engaged the PTO a few times, and it never spun up the blades.. so the slip-clutch was engaging. I tightened the bolts back up to where they were, and the noise was still present.

It almost sounds like the blades or something is scraping against something else, until it gets up to speed. I might try to make a video of it so you can hear/see.

I did raise the cutter up on some stands and crawl under it; everything looks good, clean, and the blades/pan will rotate freely by hand about 1/4 of a turn before it catches the resistance. The cotter pin and bolt on the pan securing it to the spindle are present and secure.

The gearbox does look like the top has been taken off before, and someone used gasket-maker when they put it back on -- maybe this is how it comes from the factory; but I figured JD had a pre-made gasket that fit it, instead of just anaerobic gasket maker.

 

[Thowle]

When is your 5115M going to be delivered? That should spin the MX6

Just now got the quote back on it. The lead time is 2+ months. So, no time soon. The quote for the 5115M (loaded, deluxe cab, etc), with an MX5 (loaded, with rough-ag tires), and an H260 loader was $89,000 total. I'm going to try to work that number down a bit -- seems a bit high for it all.

 

[jd110]

I guess I am a little worried about your gearbax since you said it appeared dry. The gearbox should be 1/2 full of oil. Aside from that, it is somewhat normal to have some noise on engagement on these compact tractors since the pto clutch engagement is so abrupt. The quick startup causes the swinging blades to flex, causing a temporary out of balance situation until centrifugal force can straighten them back out. The out of balance situation causes backlash in gears to chatter throughout the drivetrain and that is what causes the noise. The 5000 series and up have built in modulation of pto engagement and makes it a non issue on them. Not sure why deere doesn't have modulation in compacts, except I guess the cost would be too high and most attachments don't have alot of rotating weight to cause this situation.

 

[Thowle]

Slip clutch was for sure not tight enough.. I suppose all that noise is just because of the slip clutch?

 

[murphy1244]

Sounds like its slipping to me. How do you adjust your clutch? Do you loosen or tighten to get more slip?

 

[Thowle]

Yep, it was for sure slipping at the first; I suppose it still is after I tightened those 6 nuts up on the slip clutch plate. It's still making a very odd sound though. If it is from the slipping; I wonder if there is something up with the slip clutch, or if they all make that noise?

 

[arlen4720]

Yep, it was for sure slipping at the first; I suppose it still is after I tightened those 6 nuts up on the slip clutch plate. It's still making a very odd sound though. If it is from the slipping; I wonder if there is something up with the slip clutch, or if they all make that noise?

I'm a little confused as to why you dubbed music into a video that you want help evaluating sounds.
The clutch is definately slipping. I can see the smoke. I think the manual says to adjust the gap of the bell spring washer to 3mm. But, I'm with jd110, the gearbox may not be healthy. Can you rotate the drive shaft by hand fairly easily?

 

[Thowle]

After tightening the clutch to spec, it still makes that noise.

I can rotate the drive shaft and or blades about 1/4 of a turn before I get a lot of resistance.