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5 Posts
Discussion Starter #1
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

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

Picture 2

  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 ( 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

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

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

Picture 5


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

Picture 6

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

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

Guides installed.

Picture 9

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

Continue to part 2.

5 Posts
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

Picture 12

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

Picture 13

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

Picture 15

1,185 Posts
Thanks for posting.

79 Posts
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.

5 Posts
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.

79 Posts
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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