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Cincinnati HydroShift 10x36

O

OkOkie

Plastic
Joined
Nov 18, 2017
I'm trying to help a friend with a Cincinnati HydraShift that has a problem. It runs the spindle fine and will dial up and run up all gears. But we can't get it to run the lead screw. The gear train outside the head stock runs the QCGB input shaft. The QCGB will shift both gear selectors, but not the lead screw reversing lever. The lead screw will not turn by hand but is free from the apron controls. The cross feed lever and the carriage feed lever are disengaging from the gear train and the half nuts also will engage and disengage. We're down to removing the QCGB but I wanted to ask you guys opinion before going that far. Any help greatly appreciated.
 
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I would suspect a sheared tapered pin. From your description others here may help narrow it down.
Look at the pin or keyway on the leadscrew gear where it leaves the quick change gearbox.
 
The reversing lever on my QCGB (Hydrashift 12-1/2 x 36) is sometimes balky too, and since my lathe is down for clutch problems, I'll soon be opening that case to diagnose it.

But start with the easy stuff: does the QCGB have the correct lubricant in it, and at the correct level? Is the Bijur pump working?

As mllud22 suggested, there is a shear pin (the Cincy manual gives dimensions and material specs) between the output of the QCGB and the lead screw, which would explain why the QCGB won't drive the lead screw, but even if the shear pin is broken, you should be able to see if the output shaft of the QCGB is turning? If it's not, then I suspect something related to the reverse sliding clutch inside the QCGB is causing problems.
 
We have checked the shear pin between the lead screw and the QCGB and it's OK. I'm pretty sure we have a problem with the reversing clutch because it won't shift, but it seems to be in between fwd and rev so I just don't understand why the lead screw won't turn. The Bijur pump is working but the oil level is low. We'll correct that.
Elwood, do you have a thread started about your clutch problems? If so I would like to keep up with it.
 
Mike C. said:
If the leadscrew clutch is between fwd and rev, it's in neutral. That's why the screw won't turn.
Click to expand...


It would seem that I should be able to turn the lead screw by hand if the reversing lever is indeed in between gears?
We have disengaged the drop lever of the QCGB also.....still no joy.
 
OkOkie said:
It would seem that I should be able to turn the lead screw by hand if the reversing lever is indeed in between gears?
We have disengaged the drop lever of the QCGB also.....still no joy.
Click to expand...

You are at a mechanical disadvantage trying to turn that shaft by hand. The gear that drives the leadscrew may still be engaged with another gear / shaft. . Even in neutral it may not turn easy by hand. Truck transmissions have taught me this lesson.
Can you see if there are any other gears engaged in neutral?
The shaft alone should turn easy
 
Gears have a little play. Can you wiggle the drive screw back and forth .
 
mllud22 said:
You are at a mechanical disadvantage trying to turn that shaft by hand. The gear that drives the leadscrew may still be engaged with another gear / shaft. . Even in neutral it may not turn easy by hand. Truck transmissions have taught me this lesson.
Can you see if there are any other gears engaged in neutral?
The shaft alone should turn easy
Click to expand...
I have disengaged the QCGB drop lever and the two range selection levers to what feels like they're between two gears. The only other lever is the lead screw reversing lever, which won't move but looks to be between gears also.
 
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If it sat for some time or the feed screw wasn't shifted into gear for a while the slider is probably stuck to the shaft.
I would try some light tapping or a pry between where it slides on the shaft. Carefully the shifting forks break
If you can get to it.
 
We pulled the QCGB off and found the woodruff key under the drive clutch sheared (#27 in parts fiche). Also the lead screw drive worm was seized in the apron. It was probably the cause of the key shearing. Looked like no one had pumped the oilers in years. Dressed up the galled marks, changed the woodruff key, cleaned and re-lubed everything thoroughly, reassembled and it's running fine again.
 
OkOkie said:
We have checked the shear pin between the lead screw and the QCGB and it's OK. I'm pretty sure we have a problem with the reversing clutch because it won't shift, but it seems to be in between fwd and rev so I just don't understand why the lead screw won't turn. The Bijur pump is working but the oil level is low. We'll correct that.
Elwood, do you have a thread started about your clutch problems? If so I would like to keep up with it.
Click to expand...

Sorry, OkOkie, I missed your question about the clutch. No, I don't have a thread started, other then a WTB in the buy/sell. I'm looking for a clutch sleeve for the No. 2 Rockford Pullmore slipper clutch. I've had no luck in tracking one down.

Reading your last post, you noted that the lead screw drive worm in the apron had seized. Shouldn't that have caused the shear pin to fail first, before damaging anything in the QCGB such as that Woodruff key? Or is your leadscrew sleeve like mine, where the shear pin had broken and been replaced with something more substantial (and thus not likely to shear before something else failed)? It's like replacing a fuse or breaker with a higher rating because the circuit keeps blowing. :rolleyes5:
 
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