L1500DT Transmission Help

[jhodge]

Hello everyone, I'm a new member and Kubota owner. I have recently purchased an L1500DT with loader, low hours, good overall condition, known reverse issue. From this site, found out that it is a cross between the American models L175 and L185DT.

Once purchased and hauled home, I put in a new battery, fired it up and drove it around the yard (bump started it prior to purchase to verify it ran). All operations functioned properly except for reverse. I then parked it in the garage and pulled the shifter cover to find as described in a number of posts here that the rearward portion of the reverse gear was ground up and worn away. The mating gear on the main shaft was a bit worn, but still appeared to be ok. From there I ordered a replacement reverse gear and changed out the damaged one. This is possible to do without splitting the tractor. Remove the clutch inspection cover and feel inward toward the transmission case. There will be two bolts that hold in the reverse shaft retaining plate. These can be reached with a 3/8” drive 12mm deep well socket. Once that plate is removed, slide the reverse shaft forward and reach down in through the top (with trans. cover removed) and extract the damaged gear. Assemble in reverse order. Note: to reinstall the retaining plate and bolts have an assistant with small hands help. Overall the job will take between 4-5 hours.

Now, moving on to the issues. After the completed install and reassembly I took the tractor for a test drive. Shifted into reverse and backed out of the driveway. No issues. Drove forward and backward a couple times for about 20ft with no issues. Drove forward and took a scoop of concrete debris (from a project started that was a reason for acquiring tractor), backed rearward out of pile and proceeded to drive out back to dump by creek, approx. 350ft from the pile. Still no issues present. Then, dumped the bucket, backed up, shifted to go forward and was met with sounds of grinding. I then tried reverse and same result. Completely disheartened, I put into neutral, shut off, and towed back to the garage with the Wheelhorse (which on a side note is an awesome little tractor).

Once in the garage I pulled the shifter cover back off to inspect. The rear corner of the reverse gear was nicked very slightly. However, the mating gear on the main shaft was ground out very similar to the original damaged reverse gear. The other gears appear to be ok, but I’m not sure until I pull the transmission and inspect everything.

This brings me to my questions. Based on my research, I will need to replace the entire main shaft. Should I replace the reverse gear again? The damage is sustained is about equivalent to a 1/32” chamfer or less. What should I look out for or into specifically once the case is pulled? I already have the tractor split and supported. The service manual led me down the wrong path so tonight I have some reassembly to do and will plan to separate the trans. case from the rear differential/axel housing. Any suggestions for this? I read another member did so with a come-a-long. In addition, what other bearings, etc. should I change or would be recommended to change as just a preventative maintenance purpose while I have it apart?

Any suggestions for those who have been there would be greatly appreciated.

Thanks all,
Joel

 

[jhodge]

Hi all.
Just an update for any who read: I've completed the rebuild this weekend and tractor is back together - well all 3 main sections. End up replacing all drive gears, main shaft, main shaft bearings, clutch, pressure plate, and throwout bearing. For those who have purchased the service manual, do not follow it for transmission removal. It states to remove the axles and differential in order to remove the transmission. I should have known better, but started down that path before I realized it was unnecessary.

I have to finish up the brake/clutch linkage, hydraulic lines, misc. electrical, fluids, etc. and then it'll be back in service. I'll have pictures and such to add to hopefully help others, forthcoming.

Until then, should anyone come across this and need some help, don't hesitate to contact me. I'll try my best to give pictures and advice.

Joel

 

[North Idaho Wolfman]

For those who have purchased the service manual, do not follow it for transmission removal. It states to remove the axles and differential in order to remove the transmission. I should have known better, but started down that path before I realized it was unnecessary.

That is because what you call the transmission they call the clutch housing, and what they call the transmission you would call the rear end, or differential housing.

 

[gpreuss]

Gosh, I'm late with this information. Back when my L185DT was about a year old Kubota had a recall having to do with the gears jamming. It happened to me once, while I stopped on a very steep incline. I got jammed up, and couldn't move. Somehow I managed to get it into a gear - it was 35 years ago, and I really don't remember what I did. Anyway, I got it home from the mountains, and took it to my dealer. He told me about the recall, or free fix, and the service department had it running like new in a couple of days.
If your dealer was around when Kubota was new, he may remember something about the problem. It had to do with the gear linkage, and sounds vaguely like what you are describing.

 

[jhodge]

After I put in the new reverse gear my best guess is that the main shaft had a good burr on it that I didn't catch from looking through the shifter cover. When the fresh gear meshed with the main shaft, it must have grabbed the imperfection and loaded the shaft. This assumption is based on the lack of thrust washer - upon reassbembly I found it to me missing. I have to assume that it was either worn out over time or due to the new force introduced by the fresh gear loading the damaged main shaft. Either way, once that washer was gone, the force was able to pull the main shaft out of alignment which in turn scrapped the main shaft and a drive gear.

 

[jhodge]

I would say that section has a set of steps that doesn't belong - possible due to a translation error, etc. The steps start off correct, but the added parts of removing the axels, pulling the pig and bearing cases just seem out of place. I'm glad I stopped to rethink. Initially, those instructions seem likely as I thought the shafts continued into the rear and those components had to be pulled to release them. if you don't realize there's a set of couplings that connect the drive and PTO shafts to the rear section then it's easy to tear down significantly more than necessary. To anyone who is going to undertake a project like this, take your time and study the parts diagram.