Shuddering on left side of Z724 zero turn

[Mowbizz]

Thanks for all the input guys. I just got word that the dealer has a new transaxle arriving from Kubota this Monday, and the dealer will install and deliver the mower back to me. I asked what the part # is, he said K3811-10032. Interesting. The original P/N was K3811-10030 and both times the transaxle was replaced previously was with K3811-10030. As I mentioned above, Messicks showed that K3811-10030 was replaced with K3811-10032. But Kubota still showed K3811-10030 on their parts drawing.

After Lugbolt said that Z7XX uses Parker transmissions, I got to thinking, and here's my theory:

Parker realized there was an issue with K3811-10030 and fixed the issue resulting in K3811-10032 being the replacement. This was made available by Parker, but Kubota either had an existing stock of K3811-10030 they had to burn through, or had to go through their own red tape to implement K3811-10032 so there was a delay in sending the updated P/N to dealers. Maybe Kubota had hopes that the issue wasn't 100% of the units and that by continuing to replace problem mowers with K3811-10030 that a good unit would show up. Guess what - now the Kubota drawing shows K3811-10032:

View attachment 129689


So at least now I have hope that the issue will be fixed, I will see probably in about a month after several mows if the mower is still running well. If not, well then I've got a lot of great advice from you guys, so thanks! I'll start with checking tire slip and belt issues as you guys mentioned.

The crappy part is that I've had to pay for someone to mow my lawn many times the past 2 years while my new mower was in the shop. Also really tarnished my opinion of Kubota overall - I still can't believe there's no support if you call Kubota corporate. But if this fix sticks, I can move on. Cheers!

Great! Hope it works out for you! I’m not sure I would have been as patient as you!

 

[Lastking]

I have the exact same issue. I have the twheels, so the tire slipping on wheel is not the problem. K replaced tensioner spring which stopped it for a while(30 hrs). Started shuttering again last week.

 

[jetfisher]

I have the exact same issue. I have the twheels, so the tire slipping on wheel is not the problem. K replaced tensioner spring which stopped it for a while(30 hrs). Started shuttering again last week.

I think that is what my dealer did first (tensioner spring), and yes the issue came back but much sooner than 30 hrs, more like 2-3. After the transaxle was replaced with the new Part#, everything has seemed to be fine (all mows over the summer), until just recently. I started to notice the shuddering again a couple mows ago - I told myself it was just in my head but then it happened again. This time, it's much less severe but I'm keeping a close watch. Keep me posted on your experience, I'll update on mine, although I only have a few mows till the end of the season.

 

[Mowbizz]

I may do my last mow of the season today with my Z422…if the dew on the grass dries up sufficiently. Hopefully, no shuddering!

 

[lugbolt]

Thanks for all the input guys. I just got word that the dealer has a new transaxle arriving from Kubota this Monday, and the dealer will install and deliver the mower back to me. I asked what the part # is, he said K3811-10032. Interesting. The original P/N was K3811-10030 and both times the transaxle was replaced previously was with K3811-10030. As I mentioned above, Messicks showed that K3811-10030 was replaced with K3811-10032. But Kubota still showed K3811-10030 on their parts drawing.

After Lugbolt said that Z7XX uses Parker transmissions, I got to thinking, and here's my theory:

Parker realized there was an issue with K3811-10030 and fixed the issue resulting in K3811-10032 being the replacement. This was made available by Parker, but Kubota either had an existing stock of K3811-10030 they had to burn through, or had to go through their own red tape to implement K3811-10032 so there was a delay in sending the updated P/N to dealers. Maybe Kubota had hopes that the issue wasn't 100% of the units and that by continuing to replace problem mowers with K3811-10030 that a good unit would show up. Guess what - now the Kubota drawing shows K3811-10032:

View attachment 129689


So at least now I have hope that the issue will be fixed, I will see probably in about a month after several mows if the mower is still running well. If not, well then I've got a lot of great advice from you guys, so thanks! I'll start with checking tire slip and belt issues as you guys mentioned.

The crappy part is that I've had to pay for someone to mow my lawn many times the past 2 years while my new mower was in the shop. Also really tarnished my opinion of Kubota overall - I still can't believe there's no support if you call Kubota corporate. But if this fix sticks, I can move on. Cheers!

the change in part number could be anything, it may be that they changed a sticker on the transmission, the color it's painted, the casting, the vendor that Kubota buys it from, or maybe it's a redesign internally? Who knows? Kubota is a huge global company and when they realize there's a problem, there is a specific route to take to fix that problem-and it takes forever. Just like government, as it gets larger, the "fixes" become more drawn out. Normal, and what I call "par for the course". The downside to a company getting "that" big.

as said there were a few issues with the early Z7xx transmissions from Parker. Parker never would tell us what was wrong, neither would Kubota. When I replaced a bad one, they'd have me take it apart and take pictures. THen they'd send us a new Parker HST, we install it, bleed/test and send it to the customer.

I will say this. A lot of owners of zero turn mowers are hard on transmissions (among other things). I'm not saying that's the case in this discussion because I have not seen the equipments in question, but over the many years I dealt with lawn mowers, I'd say about 70% of "warranty" claims were neglect and especially abuse related. Problem is in most cases that can't be proven to the manufacturer's warranty dept AND we wanted to salvage customers, so we'd run it through as a normal warranty. When changing directions, most operators will just jerk on the sticks to change direction. The arms have gas shock absorbers on them that help slow down how fast one can change the speed of that wheel, helps protect the HST from damage. Directional changes, from full forward to full reverse can (and often do) put an enormous strain on the internals of the HST. Fluid changes per or more often than specified in the books are important as is keeping a fan on it (check the belt driven fan..if it's broken, the hst is GOING to overheat and fail). Similarly, keeping the hst clean helps keep it cool as well. Grass clippings built up on the hst will reduce the cooling from the fans and cause overheating/premature failure.

 

[jetfisher]

the change in part number could be anything, it may be that they changed a sticker on the transmission, the color it's painted, the casting, the vendor that Kubota buys it from, or maybe it's a redesign internally? Who knows? Kubota is a huge global company and when they realize there's a problem, there is a specific route to take to fix that problem-and it takes forever. Just like government, as it gets larger, the "fixes" become more drawn out. Normal, and what I call "par for the course". The downside to a company getting "that" big.

as said there were a few issues with the early Z7xx transmissions from Parker. Parker never would tell us what was wrong, neither would Kubota. When I replaced a bad one, they'd have me take it apart and take pictures. THen they'd send us a new Parker HST, we install it, bleed/test and send it to the customer.

I will say this. A lot of owners of zero turn mowers are hard on transmissions (among other things). I'm not saying that's the case in this discussion because I have not seen the equipments in question, but over the many years I dealt with lawn mowers, I'd say about 70% of "warranty" claims were neglect and especially abuse related. Problem is in most cases that can't be proven to the manufacturer's warranty dept AND we wanted to salvage customers, so we'd run it through as a normal warranty. When changing directions, most operators will just jerk on the sticks to change direction. The arms have gas shock absorbers on them that help slow down how fast one can change the speed of that wheel, helps protect the HST from damage. Directional changes, from full forward to full reverse can (and often do) put an enormous strain on the internals of the HST. Fluid changes per or more often than specified in the books are important as is keeping a fan on it (check the belt driven fan..if it's broken, the hst is GOING to overheat and fail). Similarly, keeping the hst clean helps keep it cool as well. Grass clippings built up on the hst will reduce the cooling from the fans and cause overheating/premature failure.

All makes sense on user neglect/abuse, I'm sure that is true in a lot of cases. However, I was consciously very gentle on my mower when new (not even pushing to full speed, definitely not doing quick turns or decel/accels) and this issue showed up with just a few hours on the engine. Also, each time it was consistently the left side (zero issues on right side). And when I received the new transaxle this summer, I was EXTREMELY gentle on accelerations, turns, etc... and still the issue is appearing. I still have <50 hrs on the mower and for this issue to show up several times while I've not been mowing aggressively at all, and always on the left side, I can confidently say my case is not user error.

Not saying you are implying this for me, but I just want to be clear that there is definitely a quality issue with my mower.