Kubota L2550DT Transmission PTO Gear Rebuild

We bought our used 1989 Kubota L2550 in 2001 to help maintain our 10 acres. The bush hog for mowing field, box scraper and wood chipper are used a lot. Ever since we bought it when you would pull the PTO lever up to engage the PTO shaft it would pop back down in to neutral now and then. This got worse over time and for the last 10 years or so I used a bungee cord to hold the lever up and in to gear as I used the tractor. Finally it got so bad that the gear would grind and pop out even with it pulled up with bungee.

So decided to split the tractor case and pull the transmission out and replace the PTO gears that looked bad. Was not obvious when I started project but once I had things pulled apart and looked at them that I have the L2550DT with Dual clutch(DC) and synchro mesh transmission. When going through the exploded parts list you will need to know this since the parts sections are broken up among these types of tractors.

Once I was through I ended up replacing the Dual Clutch assembly, main engine oil seal, all transmission oil seals and two worn PTO gears that where causing the problem. Also replaced the throw out bearing for the clutch. The reason for the new clutch and replacing all oil seals is that when I pulled the clutch the plates where covered in oil. Was not sure oil was coming from transmission side or engine side so replaced them all. also went ahead and bought all new ring clips used inside the transmission for the ones I removed to service the transmission.

Is so much work to take the covers off along with all the control linkages and then split the case that you want to make sure you dont have to take it apart again for any reason so replace any part in doubt. Some of the other internal gears had some small pitting on inside surfaces but decided they where OK since they where the large pieces in the $400 range and should last long enough.

Manuals Etc Required

The two main pieces of info you need is the expanded parts list on the Kubota USA site and the Kubota Work Shop Manual (WSM) for the L2550.

The exploded parts list can be accessed at the Kubotausa web site.

See: https://www.kubotausa.com/parts

Click through to the
Illustrated Parts List and select L2550DT for Model Name or your tractor type. Mine is the 4WD with dual clutch. The dual clutch has two clutch plates so that when you first start to let the clutch pedal out the PTO clutch engages spinning the PTO up before the transmission to wheels is engaged.

The exploded parts list is very important to see how all the parts fit together and then go back together. I printed all pages for the transmission Counter, main and PTO shafts and case so I could refer to them as I worked. Once you drill down to the specific page use the split print to put a diagram on one page and the parts list and the following page(s).

I got my WSM for $35 or so back in 2002 at the local Kubota dealer and currently might be able to get one on EBAY etc. The WSM gives the order of taking the tractor apart and putting back together with the exploded parts list giving more detail.

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Tools Etc

More or less used a metric set of socket and crescent wrenches and screw drivers. Did end up buying a good snap ring plyer set and a set of punches. The transmission contains a number of snap rings and the external linkages for brake pedals, steering and drive shaft have roll spring pins you will need punches to remove. I used a regular punch set but a roll pin punch set would work better.

Lang Tools (3495) 12-Piece Fixed Tip Combination Internal/External Snap Ring Pliers Set

Also ended up using a metal drill bit extension tool for tapping out shafts and various wood pieces for leveraging/jamming gears from turning etc as you work inside transmission.

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Also carefully bagged all parts for each section so that I could make sure that all parts where returned. Also replace all bolts you can back in the holes they came out from so you know where they go on re-assembly.

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Tractor Seperation

In general the tractor separation of transmission from engine and transmission from mid-case went smoothly. For separating transmisson from engine you push on the top of the rear tires to roll it back or forward.

For removing transmission from mid-case just used the engine crane from the side. For this stage I did end up getting a leveling bar to make fine adjustments easier. See:https://www.harborfreight.com/2-ton-capacity-heavy-duty-load-leveler-60659.html

The first thing to do is go to the WSM separation section to remove the metal covers and control linkages so that you can separate the clutch housing from mid-case WSM Pg S.S-14. I left the front end loader on the tractor dropped the bucket and propped up the front end on blocks with gears in neutral. Then a two ton engine hoist was rolled in from the rear of the tractor and strapped to the middle of the mid-case. Once the bolts are removed from clutch housing crank up the hoist to support the mid-case and roll the back of tractor back to separate the case. Make sure you leave enough room, when you block the rear, when you pull it back to be able to pull the clutch housing forward off the rear end and hoist it out.

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The steering post is then removed from the case. Next the hoist was moved to the side of the tractor and the transmission case supported by the hoist and pulled off from rear axle mid-Case and placed on a table on the side of the tractor.

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After separation the next step is too remove the steering gear case and clutch throw bearing and main shaft cover from the front of the transmission case WSM Pg S.3-7. With the PTO shaft at the bottom you have to remove both the counter and main shaft to access the PTO shaft from the top plate on the transmission. From the front, see below, you can see the configuration of the three shafts from top to bottom, Counter Shaft, Drive Shaft and PTO shaft.

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Remove counter Shaft Pg S.3-8. The front cap is pulled of from front of case and then the counter shaft is slid out the back of the Case. The counter shaft is the most complicated shaft in the transmission so as I tapped the shaft to the rear I carefully placed the gears coming off the end in order on a broom handle to keep them in order.

Take a picture to note the (3) KEY,SYNCHRONIZERS(Part#
32430-21440) held within the COUPLING and SHIFTER which can easily fall out of the coupling. When putting the transmission back together I stuck them back in embedded in grease to hold the keys in place.

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When I pulled the transmission cover off I could see the bad (2)PTO gears, in the top of the photo below, below the Counter Shaft. Gear-18 on PTO Counter Shaft-2 and below it Gear-23 on PTO Counter Shaft-1 where badly worn. I could also see that pulling up on the PTO lever would pull the two gears together better making the bungy cord pulling the lever up make the PTO work on worn gears for 10 years.

a bit confusing but the WSM calls parts list “PTO Counter Shaft-2” the “PTO Gear Shaft” as on WSM PG S.3-9.

Replaced:
KUBOTA GEAR 18 (PART#: 31351-25260) PTO Counter Shaft-2

KUBOTA GEAR 23 (PART#: 31351-25170) On the end of PTO Shaft-1

The PTO shift fork was also badly worn and no longer available so I had to order from a used tractor parts place “West Kentucky Tractor Parts”.

See: http://wkytpstore.com/

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You then go to the rear of the transmission and simply pull out PTO Counter Shaft-2 shown at the bottom of the picture below Pg S.3-9. An internal snap ring is then removed and you pull out the PTO Gear Shaft that is mounted in line behind the main shaft driven by the engine.

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Next as shown on WSM Pg S.3-10 you draw out the 16T main gear shaft from the front, remove the internal main shaft snap ring and tap the main shaft out the rear. The main shaft is located in the middle hole below. The Counter Shaft bearing is above the Main Shaft and the PTO Shaft Cover is below. Next you remove PTO Counter Shaft-1 as shown in WSM Pg S.3-12 by pulling pull out the PTO Shaft Cover, sliding the snap ring and shift fork located inside the case forward and tap the PTO Shaft out the rear.

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WARNING WARNING WARNING

THIS COST ME A WEEK OF WORK!

When you slide the PTO fork foward be aware there is a bearing installed under a bolt screwed in with a spring in the transmission case from the side.

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This ball bearing fits in to an indent in the fork rod that holds the gears in place when the PTO is engaged. If you pull the fork rod past the end the spring forces the ball bearing over in to a hole, at least on my tractor, on the far side of the fork rod channel in the case. When I tried to put the rod back in you hit the ball bearing preventing the road going back in. I ended up taking out the main gear forks to try to get the bearing out but never could. Prying from bolt hole, inside of case and heat/cold did not work. Ended up putting a piece of copper tubing in bolt hole to protect threads and drilling out ball bearing with cement carbide bit. Ball bearings are very hard and took many hours of drilling to get it out but finally got it done. Also then took some time to clean out copper tubing using a tap set and pick.

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You put the transmission back together in the reverse order that you take it apart in WSM, just start from the last page you used and work towards the front. The PTO shaft goes in easy and then the Main Shaft.

Since I had removed the main shift forks, in my failed attempt to pry out the PTO shift fork bearing, I had to put the main shift forks back in the case. The tricky part is that you have to place the main shift rod bearings in the hole under the shift forks and slip the rod in the case in to them some how. No way to do this from the bottom of the forks while in the case so needed to figure a way to do it before I put them in the case.

I ended up cutting off the tube that is used on the front of an old grease gun and inserting it through the fork and inserting the bearing and spring. I then placed the fork in the case and pushed the fork rod from the front through each fork displacing the tube while retaining the bearing in the fork. I kept the fork rod indents turned away from the rod bearings until I had rod completely inserted then turned the rod to place bolt at the front end in to shifter.

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Last but not least is the Counter Shaft, the top shaft in the case.

The Counter Shaft is trickier since you have many gears you have to slide the main shaft in too while fitting them around the shift forks. The back gears up to and just past the back fork you can just slide on one at a time as you slide the shaft forward from the back of case.

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To get the gears on the front fork was more difficult.

I ended up using the gears on the broom handle as a guide where as I slide the shaft in back from the back I would push the broom handle out of the gears I was holding towards the front.

The hardest part is keeping (3) KEY,SYNCHRONIZERS(Part#
32430-21440) held within the COUPLING and SHIFTER, as shown below, so I zip tied this set to help hold it together while trying to fit between shifting forks. Also had to move the shift forks back and forth by pushing/tapping the external shift rods, to get all the gears in.

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Main Shaft Tranmission Oil Seal

Since there was oil on the clutch I went ahead and replaced the main shaft transmission oil seal and the main seal in front of the clutch too the main engine along with a new Dual clutch Assembly.

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The internal CIR-CLIP they used has no rings for snap ring plyers so I fabricated this from a screw driver using my grinder and cut off wheel. Found this tip on the internet. Combined with another small screwdriver you can lever under ring with tool to get it started and pry it out the rest of the way screw driver.

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Once the clutch is removed I went ahead and changed the main bearing and main oil seal on the engine side of the split tractor. The Dual Clutch(DC) KUBOTA CLUTCH DUAL ASS (PART#: 32425-14200) is a single assembly that contains both clutches and simply bolts up to the fly wheel.

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I used the “stuff wet toilet paper in to the main bearing with a bolt” method to remove it (Google it). Worked well so did not need to buy the bearing removal tool. To replace the main oil seal I removed the 16 bolts around the bearing case cover. Then removed the cover with the oil seal in it where I could easily remove the old oil seal on the bench and press in the new one before re-installing in the tractor.

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It is not that clear in the WSM but when re-installing the fly wheel you need to line up the plate under the bolts with the holes in the fly wheel before trying to put the fly wheel on. The bolt holes are not symmetrical so you align the dimple on the plate to the hole in the flywheel, as shown below, before you try to place fly wheel on tractor. Then when you lift flywheel to put on tractor you align the hole and dimple with the small hole between the bolt holes on the main shaft.

After the fly wheel and new clutch installed just went in reverse order in WSM using engine lift from the side to put transmission back on rear of tractor. Then rolled engine hoist back in from back of tractor to lift back end off blocks and rolled forward to bolt back to front end.