77 JD 8430 clutch won't release

cact34r

Member
I picked up a one-owner, very clean 8430 from an estate sale with a clutch that won't release. 7k hours. It looks like the previous owner started looking at the clutch valves on the left side
of the tractor prior to his passing. I bought it expecting it to need a clutch, but as I get started was wondering what other things could cause this. The clutch pedal cable is moving the
valve arm, but the tractor cannot be put into gear although the synchronizers will try if you apply pressure to the gear selector. They were moving it around by starting it in gear and that's
the way I drove it home, so no clutch slipping of any kind. Any advice is greatly appreciated.
cvphoto47628.jpg
 
Clutch is hydraulically ENGAGED and there's a pressure test port in the clutch valve you've been looking at. Port is marked "CL".

(There's two more test ports for PTO clutch and brake, be SURE you are checking at the correct test port.)

As I recall, pressure at the port should be around 170 to 180 psi with clutch engaged, then drop to zero when the clutch pedal is depressed.

If it DOES drop to zero something is mechanically wrong in the clutch and a split will be required, for sure to repair it.

If pressure does NOT drop to zero, there's clutch valve issues.
 
Following up - I tested the pressure and found it to be correct and it did drop to 0 with the pedal depressed. Finally got time to get it in the shop and found all the fingers broken off the clutch casting.
 
Having trouble getting pictures to post - but all the casting mounts on the back of the flywheel are sheared off, and all of the fingers were in the clutch sump still attached to the broken pieces.
 

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