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rusty wrench
Frequent Visitor

Any Old J.I. Case mechanics ?

I've got an old case 970 that has me really stumped.  While I was chopping haylage, I stopped to change wagons. When I started up again, I engaged the pto clutch, then opened the throttle. The chopper came up to speed, then started coasting back down and came to a full stop, with pto engaged and full throttle. After I determined that the clutch linkage  was all working, I tried again, same result.  About then I also discovered that I seemed to have no hydraulic function at all.( steering, power shift ,3 pt or remotes )  with full throttle. Next I cracked the fittings on the pump and found no output at all.  I then  took out the six bolts and  pulled the pump off. I grabbed the splined shaft in the housing (on tractor,not the pump, which I had laid aside) and turned it by hand.  After dinking around a bit, I could no longer turn it by hand. I then decided that I must have stripped the splines on one of the shafts or couplings inside. I put the pump back on and connected up started the engine and had  normal function of hydraulic system. So I unhooked the chopper and gingerly drove the tractor about 5 miles home. I rented a tractor to finish chopping, and then worked a 4 day swing at the paper mill. When I finally got to it, I drained out the oil and removed  the pto asembly from the rear of tractor. I pulled that long shaft and inspected all the couplings and  looked carefully at the splines on the shaft up in the front.  Found all in perfect shape. While I was in there, I also dismantled and inspected the pto clutch, which I had replaced-rebuilt two or thee years ago and might have 150 hours on it, at the most.  I could not find anything wrong with the clutch either, so put shat back in coupling and tried to turn it  by hand. I could not budge it, so pretty well ruled out a stripped spline in flywheel or transmission shaft. When I put all back together, Hydraulics work fine, pto shaft turn when clutch is engaged, stops when disengaged, but will not even run a forage blower empty or take any load whatsoever Any help, suggestions or ideas are greatly appreciated.  TIA  

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6 Replies
Honored Advisor

Re: Any Old J.I. Case mechanics ?

Could it be a loose detent screw allowing the pto to slip into neutral when under load? Good Luck.

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Veteran Contributor

Re: Any Old J.I. Case mechanics ?

Sounds to me like you sheared the rivets off that fasten the female splines to the pressure plate on the engine clutch which gives you live PTO& hydraulics, I am assuming it has a live PTO, I fixed a IH966 for the same thing also on a forage chopper they are really hard on that. Dan

 

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Re: Any Old J.I. Case mechanics ?

From your detailed description of the problem, I would suspect the PTO clutch is slipping under heavy load. 

 

It may have sheared rivets as someone else has suggested.

 

If splines, couplings, or gears were stripped, it would make a horrible "new" noise when engaged and slipping.

 

 

 

I am not a Case expert, but have a lot of experience working on older equipment.

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rusty wrench
Frequent Visitor

Re: Any Old J.I. Case mechanics ?

I finally found it.  It waas a rinky dink little spring pin behind the back plate of the pto clutch.  when that pin either broke or fell out,  the pressure on the clutch piston would push that hydraulic pump shaft back just far enough to disengage the splines and stop the pump.  As long as I didn't try to use the pto, the pump would work just fine.  Thank you fellas for your good advice and suggestions.  The hair that I pulled out should grow back in a while!

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Re: Any Old J.I. Case mechanics ?

just wondering if you ever figured out what the problem was cause mine is doing the exact same thing

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Senior Contributor

Re: Any Old J.I. Case mechanics ?

Did you leave it in reverse with the PTO engaged?
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