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6x4 Gator hard gear engagement. Primary clutch not releasing - how to fix for $32

I have to start by saying I did all this more than a year ago and tried to post the write up then. However the user ‘friendlyness’ of the site made it frustrating and near impossible to post the info. I tried lots of different ways and gave up. It now seems pretty good, but they say add pictures to help, but there still is only a limit of 10. That still isn’t enough, but it’s easy to cut and paste now, so I’ll add part 2 to the next post.

Part 1

Symptoms
Crunching engaging gears. Sometimes drives secondary clutch at idle. Primary clutch makes a click/popping noise when engine turns off.

Possible cause
Primary clutch rollers damaged/ missing.
Picture 1
13426


Picture 2
13429


Solutions
  1. Replace whole primary clutch at about $500. Special tool required.
  2. Replace spider assembly at $200. Different special tool required.
  3. Find another solution.

Option 3A
After a bit more internet searching I came to the conclusion that these gator clutches were probably made by Comet Industries. I managed to find a company called Belt Palace (https://beltpalace.com) that sells a Comet 72C for about $250. Their part number 218360C. This was not on their website. Not knowing how difficult replacing the spider would be, I took a gamble and bought a complete clutch from the really nice and helpful folks at Belt Palace. Here’s the old and new clutch:

Picture 3
13427

So, indeed the Deere gator clutches are Comet 72C clutches.

Now the cam weights are worth mentioning. My old one has J10 weights at about 135 grams

Picture 4
13428

Whereas the new Comet 72C has about 113 gram cams.

Picture 5

13432


From the Gator Technical Manual TM1518 it may be that the cam better matches the diesel version.

Picture 6
13431

However, my old clutch should have had the D shaped J10 weights, but actually has J10 round holes, so confounds the manual data.

The new clutch with lighter cams works fine in my 2004 gas 6x4 gator. So job done for half the price from the dealer! Now I have this old clutch, with not much wrong with it. On to option 3B.

Option 3B
The only thing wrong with the original clutch was the worn and missing rollers. Figuring out what replacement Comet rollers were suitable seems impossible for this obscure Comet 72C. After reading about someone using drill guides, I figured I’d give it a go. The rollers dimensions appear to be 1/2” od x 3/8” id x 3/8” long. Press-in style drill bushing are easy to acquire at a few places. I found the ones I needed at McMaster-Carr 8491A726 for about $8 each plus about $8 shipping.

Picture 7
13433


These guides needed to be ground out slightly on the ID. It was only a few seconds each with the dremel sandpaper drum.

Picture 8
13435


Guides installed.

Picture 9
13434


The mechanism seems to function okay, but I have not yet tried the rebuilt original clutch with new ‘drill guide’ rollers on the gator. It’ll be a spare.

So you could fix the gear crunching for about $32.

Additional Information - Specialist Tool Alternatives
Clutch removal tool.
After looking online there are lots of instances of home made versions of John Deere tool JDG813-1. I found the 9/16-18UNF x 3” long bolt with 1/2” OD x 2-1/2” long stud works well with air impact gun:

Picture 10
13430


Continue to part 2.
 

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Discussion Starter #2
Part 2

Spider removal tool
After looking online there was not a lot of info on options for the JDG813-3 tool or even what it really looks like in real life. There were some indications that it would be difficult to remove the spider and clutch damage was possible (which is why I went with the new whole clutch).

Picture 11
13436


Picture 12
13437

My spider was actually very easy to unscrew with the Craftsman 20523 oil filter wrench that I had.

Picture 13
13438

To prevent rotation of the stationary pulley I used a 2x4 with a couple of lag bolts at 3-5/8” apart, plus a couple of soft jaw clamps:

Picture 14
13439


Picture 15
13440
 

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Thanks for posting.
 

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I made a holding fixture almost like that, only difference is I used 3/4 plywood and had 4 bolts, but that was before I seen it was only torqued at 100ftlbs.
 

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Discussion Starter #11
It’s more than a year since I did this stuff and have not been researching Other posts any more. My logic is the existing rollers are too soft, hence the failures, so harder is worth a try.
 

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There is some merit to that Scott but the main problem is a buildup dirt that stops the bushing from spinning, so if you get harder ones you'll want to decide is it cheaper to replace bushings or weights. Good cleaning once in a while will extend longevity, I pull mine down once a year.
 

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Great writeup. Thanks for sharing. Curious what the original part number was on the primary clutch that matched the Comet clutch?

I have a few gators here. 2010 HPX gas with AM138485 which looks similar to the picture above 3 spokes in the spider.

Anyone match up a primary clutch from a newer Turf gator AM138536 to a comet ? This one has 4 spokes in the spider.
 

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6x4 Gator hard gear engagement. Primary clutch not releasing - how to fix for $32

I have to start by saying I did all this more than a year ago and tried to post the write up then. However the user ‘friendlyness’ of the site made it frustrating and near impossible to post the info. I tried lots of different ways and gave up. It now seems pretty good, but they say add pictures to help, but there still is only a limit of 10. That still isn’t enough, but it’s easy to cut and paste now, so I’ll add part 2 to the next post.

Part 1

Symptoms
Crunching engaging gears. Sometimes drives secondary clutch at idle. Primary clutch makes a click/popping noise when engine turns off.

Possible cause
Primary clutch rollers damaged/ missing.
Picture 1
View attachment 13426

Picture 2
View attachment 13429

Solutions
  1. Replace whole primary clutch at about $500. Special tool required.
  2. Replace spider assembly at $200. Different special tool required.
  3. Find another solution.

Option 3A
After a bit more internet searching I came to the conclusion that these gator clutches were probably made by Comet Industries. I managed to find a company called Belt Palace (https://beltpalace.com) that sells a Comet 72C for about $250. Their part number 218360C. This was not on their website. Not knowing how difficult replacing the spider would be, I took a gamble and bought a complete clutch from the really nice and helpful folks at Belt Palace. Here’s the old and new clutch:

Picture 3
View attachment 13427
So, indeed the Deere gator clutches are Comet 72C clutches.

Now the cam weights are worth mentioning. My old one has J10 weights at about 135 grams

Picture 4
View attachment 13428
Whereas the new Comet 72C has about 113 gram cams.

Picture 5

View attachment 13432

From the Gator Technical Manual TM1518 it may be that the cam better matches the diesel version.

Picture 6
View attachment 13431
However, my old clutch should have had the D shaped J10 weights, but actually has J10 round holes, so confounds the manual data.

The new clutch with lighter cams works fine in my 2004 gas 6x4 gator. So job done for half the price from the dealer! Now I have this old clutch, with not much wrong with it. On to option 3B.

Option 3B
The only thing wrong with the original clutch was the worn and missing rollers. Figuring out what replacement Comet rollers were suitable seems impossible for this obscure Comet 72C. After reading about someone using drill guides, I figured I’d give it a go. The rollers dimensions appear to be 1/2” od x 3/8” id x 3/8” long. Press-in style drill bushing are easy to acquire at a few places. I found the ones I needed at McMaster-Carr 8491A726 for about $8 each plus about $8 shipping.

Picture 7
View attachment 13433

These guides needed to be ground out slightly on the ID. It was only a few seconds each with the dremel sandpaper drum.

Picture 8
View attachment 13435

Guides installed.

Picture 9
View attachment 13434

The mechanism seems to function okay, but I have not yet tried the rebuilt original clutch with new ‘drill guide’ rollers on the gator. It’ll be a spare.

So you could fix the gear crunching for about $32.

Additional Information - Specialist Tool Alternatives
Clutch removal tool.
After looking online there are lots of instances of home made versions of John Deere tool JDG813-1. I found the 9/16-18UNF x 3” long bolt with 1/2” OD x 2-1/2” long stud works well with air impact gun:

Picture 10
View attachment 13430

Continue to part 2.
Thank you for a great article! I am trying to gain more information on the primary clutch and this was better than anything else I have read. I do have a question for you regarding the clutch that you rebilt with the pictures shown. n Was this the new style or the old style? Mine is going to be the old style based on my serial no. Can the old style clutch be replaced with the new style or do you have to make modifications? Thanks for your time.
 

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Another question for you on the roller replacement for the clutch: How do you remove the pins from the arms to replace the rollers? I don't want to break anything trying to remove them!
 
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