ZD331 PTO shuttered and then stopped?

forceten

Member

Equipment
BX 25d
Sep 4, 2015
268
21
18
New Jersey
Was doing what I thought was gonna be the last cut of the season. As I started to cut i heard some funny noises with the mower deck spinning. Popped open the lower panel and I could see the belt jumping a little bit. Not slipping but like binding up for a fast sec and the idler arm jumping. Looked a bit more and then the pto/drive shaft just shut right off.


PTO will make a noise for a sec if I try to re engage it and once started to spin the shaft for a rotation or two but then stopped.

Didn't have time to look at it more today, but will this week.

Any thoughts on where to start? My first thought was the gearbox..... But open to other suggestions? The mower drives and moves fine. Not sure of the pto side of the transmission could be the problem also. Was gonna disconnect the pto shaft and see if the trans pto would spin without the shaft, and that might narrow it down to the gear box.
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
4,807
1,575
113
Mid, South, USA
If the shaft going to the gearbox won't turn, then it's either transmission/pto clutch related...OR...perhaps the engagement linkage is bent/out of adjustment.
 

forceten

Member

Equipment
BX 25d
Sep 4, 2015
268
21
18
New Jersey
So thought I would just look at the gearbox before bed tonight. Opened up the top and side plugs. Gearbox looked empty/dry


Put some gear oil into the top plug, as I was putting it in, under the gearbox leaked it right out, almost as fast as I was putting it in.

Haven't worked on a gearbox before but I assume there is a seal on the bottom that went bye bye.

Not sure the the whole gearbox is shot or not. Maybe a rebuild or new one depending on what i find when i take it off.
 

forceten

Member

Equipment
BX 25d
Sep 4, 2015
268
21
18
New Jersey
I still have to take off the gearbox this weekend to see just how bad it is inside.


If it is indeed shot, is it better to rebuild the gearbox, or just go ahead and order a new one?
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
4,807
1,575
113
Mid, South, USA
You can see what you need to from the top plug. Remove it, grab a good flashlight and look down inside. If the gears are trashed and you're seeing metal shavings in the bottom of the box, it's junk.

I have seen gear kits on eBay. Quality? Questionable. I've got about a dozen gearboxes sitting out here that are all trashed and I may buy a gear kit from eBay and see if they're any good. Based on previous experiences with eBay's garbage, I am not expecting much....

I can tell you this. I've rebuilt a few of them by request. They ARE rebuildable, and Kubota sells the parts for them individually. The problem is the cost of parts isn't much different than the cost of a new gearbox. AND...once you add labor (if you had to pay someone $100/hr like at a dealer), you're well beyond the cost of a new assembled box. Remember....the cost of parts isn't just gears, bearings, and 2 seals, it's also shims-and those suckers are more expensive than the need to be and you don't know what shims you need until you start mocking up the gearbox, then you have to adjust using different thicknesses or combinations of thicknesses by stacking shims, thus you need a nice selection of them. Thankfully (in my case) I have a selection of them because of all of the boxes I've replaced over the years. Kind of OT here but I just used one to shim the input shaft bearing on a Borg-Warner T5 manual transmission-since BW (now Tremec) doesn't offer the shims in that size anymore. Anyway....I don't rebuild them often and when I do, they're done correctly-and cost more (usually) than replacing it. Sometimes an owner will just request a rebuild and I have no problem with that as long as they're understanding of the cost differences.
 

forceten

Member

Equipment
BX 25d
Sep 4, 2015
268
21
18
New Jersey
So popped the top cover (without taking the gearbox off yet)

I was expecting it to all be trashed inside but its not. There was one metal shaving though I pulled out.






 
Last edited:

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
4,807
1,575
113
Mid, South, USA
Gears are worn.

Not "trashed" (yet) though.

There is a "feather key" in the lower shaft that spins the pulley. Pull the box, remove pulley, and see if the key is sheared.
 

forceten

Member

Equipment
BX 25d
Sep 4, 2015
268
21
18
New Jersey
Gears are worn.

Not "trashed" (yet) though.

There is a "feather key" in the lower shaft that spins the pulley. Pull the box, remove pulley, and see if the key is sheared.

Trying to do a little at a time in between jobs (I work 2). So when I get home - ate a fast dinner - worked on the mower for 30 mins, then headed out to job #2. I will definitely have more time this weekend to look at things.

First - thanks lugbolt for your advice. I'm a mechanic but not a mower mechanic. I can figure most things out if its mechanical, just need a push in the right direction for things I haven't worked on before.

So tonight I removed the pto shaft, took the belt off. Started the mower up - pto/trans spun no problems. Not under load of course but I don't think the trans/pto is the trouble.

Now the three spindles, the right one spins very freely. I can spin the pully and it will keep spinning a bit. The left spindle however is very tough to spin. I can spin it but takes some effort. So I assume that spindle is bad, and maybe it put a drag on the gearbox, and that popped the lower seal, fluid leaked out and then overheated. The center spindle, and gearbox will spin free but does get hung up once in a while. If I look inside under the bottom gear I can see another piece of metal that is getting bound up. So I assume under that gear is a bearing. Maybe overheated and the lower bearing ate itself a little.

This weekend I will pull off the gearbox and look better what happened.


Right now looks like left spindle, and gearbox lower seal and bearing maybe. Not sure the the spacers goes on the lower shaft and thats what I see shredded a bit. If so from your description it will be a pain the get the shims correct without a bunch of them.......

Still cheaper than buying an entire gearbox if it just needs some shims/spacers, a bearing and lower seal.