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Discussion Starter #1
I have recently replaced the travel control plate on my 646. Forward travel now seems to be very strong, with good response from the speed control pedal. However, I've clearly done something wrong, as reverse has almost no power at all, barely enough to move the machine. Looking at the linkage, it seems that when the direction control lever is in the reverse direction and the speed control pedal is pushed the linkage tries to push in the TCV spool, but the combination of the spool being able to turn and the ball joint movement, the linkage simply turns to the side and barely moves the spool. Clearly, I have something wrong here, but I'm not sure how it EVER worked like this. I'll try to upload some pictures tomorrow, but if anyone has any ideas I would greatly appreciate it!
 

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Discussion Starter #4
Thanks for the links to adjusting the linkage, that will be really helpful.

I've uploaded a video of the problem I'm having. Fortunately for me, the previous owner cut out a section of the floor making accessing the travel linkage much easier than crawling under the tractor. The forward direction seems to work easily, but as you can see when shifted into reverse, the linkage allows the valve spool to simply spin rather than push in. Has anyone seen anything like this before?

Here is a link to the video on YouTube.
 

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I don't know how the PO got that to work. Thats the WRONG valve for that tractor. Both spools should have the ball joint that the lower, lift control has on it.

That joint at 90 degrees to the spool is from a old old 4xx tractor.

See if the end of the spool is drilled and tapped for 5/16 fine thread. If so you should be able to get a ball joint and put it in and get it working.
 

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The part manual for that tractor should be online here: https://casecoltingersoll.com/showthread.php/11113-Case-644-646-648-Loader-and-Loader-Backhoe-Tractors Look for the section on Valve - control Linkage, around page 65 and it will show how that is supposed to be assembled.

The joint on your 'lift - 3 point' control looks correct, and you could swap the ball joint out of that side into the travel side and I think you'll then see how it supposed to work. New joints are readily available: https://salempwr.com/c19025/ Also good picture of what the part looks like..
 

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I don't know how the PO got that to work. Thats the WRONG valve for that tractor. Both spools should have the ball joint that the lower, lift control has on it.

That joint at 90 degrees to the spool is from a old old 4xx tractor.

See if the end of the spool is drilled and tapped for 5/16 fine thread. If so you should be able to get a ball joint and put it in and get it working.
That is not correct. The valve is the correct valve. But obviously the linkage parts are wrong by the way it is not working. I attached a link to the correct parts diagram.
 

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Thanks for correcting that.. I should have said the linkage looks wrong..

I've gotten a hold of one of the TCV valves with the 90 degree linkage for parts, but I never realized that they put those in the 1st 646 that were made.. Hmmm. if the rod #19 C17557 is gone the only work around would be to drill and tap that spool to 5/16 fine thread like the other spool and use the inline ball joint like the later models.

Or, I guess MAKE a new #19 rod.. Which Steve you or I could do in our shops, Not so sure how shgreen can accomplish that..
 

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Discussion Starter #10
OK, looks like the linkage is wrong I guess. I've had this tractor for a few years now and I'm not sure how it has been working at all. Maybe the 90 degree ball joint piece was seized up or something, preventing it from just turning. Anyway, I removed it and yes, the end of the spool is tapped! I've got the new linkage bolted directly to it now and it seems to be working just fine. I'll have to adjust it's length to maximize the movement, but it is drive-able again!
 

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The OP.

Seeing his avatar, I remember he had trouble starting the clone, and I think some one said the clone wasn't big enough. Just wondered where he went with it?
 
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