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Discussion Starter #1
Hello everyone, We're having a howl/gear noise from our dual range cylinder drive gearbox. It's had it since we bought it used and we removed it before wheat harvest and had it gone through with nothing found wrong. No shavings, bad bearings, pins, gears, or anything. A couple of new bearings were installed and we re-installed it onto the 9600. We tried it out when we harvested wheat and it still had the loud whine/gear noise it always had. The intermediate drive sheave has a howl too and we plan to re-bearing and re-cam it soon. Will this sound transfer to the dual range? It (gearbox) doesn't do this when running direct. Are these naturally noisy? Our old 7720 T2 didn't make a sound in 4600 hrs. Any comments would be great. Thank you in advance.
 

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Those dual range gear cases are always somewhat noisy due to having straight-cut gear teeth but some are just noisier than others. I've had several customers with this same complaint and pulled the gear case apart and found nothing as well. Those cases are still running strong today, hundreds of hours later. Just be sure to keep the oil level up, change it regularly, and have the backlash set properly on the main shaft.
 

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Are you hearing the noise externally or in the cab? Is it the same noise it made before repair? Do you lube the lower variable sheave cavity yearly? Is the variable belt in good shape - no missing cogs or burn spots?

jd
 

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Well first thing, are you running it in wheat????should be locked up during wheat and most cases soybeans, with that being said the internal parts are not being used???so I would look elsewhere, I bet you have a bad bearing on the intermediate drive.Also check the lock out arm rubber bushing they have been known to slide over and cause the arm too rub and transfer noise, a whine in the cab.Also last thing have you replaced a intermediate drive belt lately?????have you adjusted the intermediate belt?????also known as sheave gaps?????this could also add a whine to the drive line.
 

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Discussion Starter #5
Thank you for the responses. Dual range only makes noise when engaged with the arm and the gears are turning. It is silent when running direct. It is audible in the cab and externally while walking beside it. (Sounds like an IH 1066 tractor transmission while pulling a plow!) We first noticed the noise in the fall while shelling corn with it engaged. It sounded bad enough that we ran it in high speed as slow as it would go. We cracked a little corn, but not as bad as I thought it would. You can hear it make a little noise when not under a load and it gets really noisy when a crop is going through the cylinder. It was removed and taken to JD service to have it checked out before this years wheat harvest. Nothing found wrong however a couple of bearings were replaced internally and the unit was shimmed up and set before they let us take it home. We engaged the unit while cutting wheat only to see if it would howl and the noise is exactly the same as before it was worked on. We ran it direct at about 880 RPM while cutting wheat (this year). The intermediate drive belt was new last fall, no burnt spots, and it gets greased. There is a howl in the intermediate drive (two howls from two locations) after the soybean spraying is completed and the wife and kids get to go camping we'll tear into that and replace the bearings and perhaps the cams while it's apart. I'll make a note of the arm touching and transferring noise. We just don't want to tear that thing up. Was told it's a $6500 gearbox new from Deere, won't go that route but still scary! Maybe it's just the nature of this beast but the 7720's dual range never made a sound...good combine. Thank you gentlemen!
 

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The noise from the variable belt (especially the newer belt) is common. With tension still on the lower variable sheave measure the width of the pulley spread on top and bottom, they should be about the same, if not its time for bushings inside. I then would take the variable belt off and slack the cyl belt and rotate the intermediate sheave and see if you have a rough bearing - If any doubt do the inside one first, the outer is easy to change.

If your dual range checked out ok when it was apart, I wouldn't worry to much - pull the drain plug every so often and check for sharpnel on the magnet. However, I would take a good look at the rubber bushing inside the arm that pins the drive in low speed - it uses a rubber bushing (same part #) as a 20 series combine chaffer swinger, if it's bad or going bad then and noise is transferred right thru that arm and sounds bad.

Let us know what you find.

jd
 

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Discussion Starter #7
Well, we know for certain where the problem is...now what?? The noise (howl) is coming from the dual range gearbox. After wheat harvest the intermediate drive bearings were replaced as well as the cams. The isolator bushing for the lockout arm was replaced; the arm had moved over against the bracket. The JD service manager came out during soybean harvest to listen to it in operation. He said he never heard one howl that loud before. The cylinder shaft has a slight bend to it on the end where the Dual range mounts - .030". The JD store had an old Dual range from a salvage combine and offered to let us try it. We put it on yesterday and tried it today. Quiet as a mouse!! No noise whatsoever. Our box that we took off sounds terrible and the slower it runs the lower the pitch and the louder it sounds. We also put $700 in ours before wheat harvest. What does everyone think...run the old one and put up with it screaming at me all day or buy the quiet one. Am I being to picky here or am I justified with my concern with the noisy one?? Any suggestions welcome...except trading the combine. The rest of it is in great shape! Thank you all in advance!! Beavis
 

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Did the dealer go through it the first time or you. If dealer did I would say I'll use the used one until you can get mine to run nice and quiet like it. Also there should be no more bill from here on out. Noises bother me that you know shouldn't be there.
 

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beavis.. I know how to help your problem. I have a 9500 that did the same thing and I was sure it was falling apart, but finally I figured out that the arm that you pin in place to get the thing in low range has a rubber bushing in the front of it. Take that arm off, press in a new bushing. They last about 800 hours. This quieted mine down to the point that it is not bothersome at all. Not gone, just quiet.

I can't believe nobody else knows about this.
 

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thanks to deere fever,I started hearing noise in my dual speed cyl and disconected it,checked oil and changed it with no fillings,when i read your post I checked my lockout arm and the rubber bushing was completly wore out,thanks
the combiner
 
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