Detroit Mower - Case VAI - lift mechanism

Hello,

I put this same post in the Case / DB forum, but thinkin' this might be a better place for it.
http://ytforums.ytmag.com/viewtopic.php?t=497820


I have a 43 Case VAI that I've been tinkering with. Gettin' 'round to the mower. I'm a complete newbie to this tractor thing, but not afraid to turn a wrench as long as I have a general idea of what I'm gettin' in for.



Plate on tractor i.d.'s the mower as a CD 14, after some research here a Case Detroit mower. It's a mid mount. This VAI has no hydraulics, but rather uses a pulley driven gear box of sorts that drives the main drive shaft to the sickle-knives and has a pulley with cable that raises and lowers the whole sickle bar. I got all the grease fittings cleaned up an injected with new grease, got the belts adjusted, pto shaft works o.k, little slopply I think, that's a topic for another post.



Sickle drive shaft and knives move along just fine. Pulley for adjusting height is another thing. It barely moved by moving the lever attached to the gear box. Looked in the square filler plug on top, looked liked grease or very old gear oil on the visible gear. There are some other square plugs towards the lower back side of the gear box. I put in some 80-90W gear oil, didn't help, thing doesn't move at all. I suspect I have some gear or engagement lever or maybe some sort of friction plate that isn't grabbing properly or just plain worn out. Before I open the top of the thing I was hoping someone here might have some experience with these things before I open Pandora's box.


Ok, I popped the top of the mower gear box. No visible signs of damage, broken gear tooths etc. The first photo is looking straight down into the gear box. Top of photo is towards front of tractor, pulley with cable to raise/lower sickle is attached to large brass gear on right side of gear box. There is a worm gear beneath this large brass gear. There is a small gear at the end of the worm gear shaft that engages the large gear towards the front of the gear box. On the end of the shaft towards the rear of the gear box there is also a small gear, but at this end there is a chain that attaches to a large gear at the rear end of the main shaft going through the gear box.


At each end of the of the main drive shaft going through the gear box there appears to be what I'm calling a clutch pack. Some sort of wet clutch pack I'm guessing. In between the two clutch packs are what looks like three large washer, the center washer actually has ball bearings in it. What's not shown is those three large washers get covered by a half moon retainer that has a post on it each side of it that a fork, similar looking to shift fork, that is attached to the external lever on the gear box. What I think is supposed to happen, when you move the lever, the shift fork then presses the clutch pack, either front or rear depending upon how you move the lever, compressing the clutch pack and that will then drive the gear, which then drives the worm gear, brass gear and pulley etc.


I drained whatever goup was in there, flushed it out with kerosene, and some brake cleaner. Then put some Case IH Hy-Tran Hydraulic fluid in it, which says on the container for hydraulics, transmissions, wet brake and clutches. Not knowing exactly what these "clutch packs" are they appear to be a wet clutch of sorts. Anyhow no luck at all, nothing happens when I move the lever.

So I'm scratching my head trying to figure out what might be wrong. I'm thinking either the clutch disc's are just completely worn out. Or the worm gear shaft bearings are siezed, bound up in some way, so that even though the clutch packs may be engaging there not strong enough overcome the binding on the worm gear and move the worm gear shaft. Really don't know, just guessing, right now. I can't move the pulley, brass gear at all by hand, not sure I should be able to or not anyhow. Don't understand how the sickle stays in position, if neither clutch pack is engaged when the lever is in the neutral position. There must be some degree of resistance in order to prevent the sickle from just always dropping to the ground under it's own weight?

If anyone has seen anything like this in the past and/or has any hints or clues as to what to try next please let me know for I'm at a loss, other than a total disassembly.


Any help would be appreciated.

thanks,

DP

Just a couple of observations.
1) A worm gear like that is self locking unless the worm is turned.
2) If those are clutch packs, then is the wishbone lever which moves the slider back and forth working properly?
3) If you put a pry bar on the large gear at either end of the gearbox will it turn the worm gear to turn the pulley in either direction?

4)If the big gears turn the worm gear, the output shaft isn't frozen up.

Just asking.

Thanks for the input. I think my next plan of attack is first try as you suggest and see if I can get a pry bar to move the large gear on the main drive shaft and see if it can move the worm gear.

If it does, then perhaps there is something wrong with the half-moon and fork that go over the center washers as you mention. There"s not much to it, a shift fork of sorts, very heavy duty, looks like a cast part, not your typical tranny shifter fork. Half-moon appears to be a cast part as well. Center underneath of half-moon does show some wear, maybe enough such that it doesn"t engage and push the washers enough into the clutch packs? I dunno" maybe. I'll take a closer look at it when I open it up again.

Thanks

Just in case anyone searches for a similar topic in the future. I finally got around to this again. Took another good close look at the yoke, shifting fork looking thing that mates to bearing carrier inbetween the clutch packs. Tried reinstalling it and actuating it numerous times. Finally the lightbulb came on, seems so obvious now, why can I move the lever so far yet the space in the gear box is so small. Uh duh, cause the yoke is slipping on it's shaft. Couldn't move it by hand and it appeared all frozen/crudded up that there was no way it could slip. But after picking away at some of the crud I noticed a small hole that appeared would hold an allen head screw key of similar. More picking, cleaning, hole on the other side, ah hah, broken bolt or pin of some sort. After disassembling the whole yoke / shaft mechanism, and cleaing it up real good. Put a hardened bolt in holes for the yoke and shaft. Lever only moves couple of inches now vs the foot+ it did before and lift mechanism works like a champ. You think by now I would have learned to check the obvious, but no that's too simple.

thanks for the suggestions.