clinter36
Bronze Member
This is a follow up to my thread about a week ago regarding a dragging (failing to disengage) Ever Clutch on my Kubota L4850. BTW - thanks for all your help.
I have since spoken with a number of dealerships/parts places, scoured the internet for information, and spent days studying the service manual. What has resulted is a growing knowledge of the Ever clutch / hydraulic shuttle system found in the L4350, L4850 and L5450. (There was also a wet clutch version in the L2650, L2950, L3450, and L3650 how close it was related, I dont know)
I am completely baffled in the lack of information and understanding of this system particularly from many dealers a few of which had never heard the term Ever Clutch. I will say however that the staff at Messicks has been unbelievably helpful in providing information.
Anyway, I am starting this thread to cast the information that I have obtained out into the world. In my current situation, I will be splitting my tractor and replacing/rebuilding the Ever Clutch. I am planning to continue to post my findings in this thread along with any helpful advice or pictures as I go through this process.
Here is the overview of the systems as I know it:
The L4350, L4850, were offered in 3 different clutch/transmission arrangements. The L5450 offered only the dry dual clutch and Ever Clutch.
L4350, L4850, L5450 Model designation: MDT (Manual shuttle, dual traction = 4x4)
- From the service manual: the manual shuttle type tractor is equipped with a dry type dual-stage clutch. Operating the PTO clutch pedal, the traveling clutch and the PTO are turned on and off one after the other
- This clutch system has two clutch disks one right after the other within the clutch housing. One clutch is the traveling clutch the other is the PTO clutch.
- The shuttle system is manually operated
L4350, L4850 Model designation: HDT (Hydraulic shuttle, dual traction)
- From the service manual: The hydraulic shuttle type tractor, on the other hand, is provided with a dry type, single-plate clutch. With the clutch pedal pushed down and released, the traveling clutch and PTO clutch are turned on and off at the same time.
- This clutch system has only one dry clutch that operates both the PTO and traveling (they are not independent)
- The Hydraulic shuttle system incorporates a separate forward and reverse wet clutch pack within the transmission that allows the tractor to be operated with only the shift lever on the column. This clutch pack is operated via hydraulic pressure through a control valve assembly mounted on the right side of the transmission. (** this is important because the Ever Clutch is virtually identical, however is operated with a different control valve assembly mounted on the left side **).
L4350, L4850, L5450 Model Designation: HDT-W (Hydraulic shuttle, dual traction, wet clutch = Ever Clutch)
- From the service manual: On the Ever Clutch type tractor, the drive train clutch is a hydraulically actuated wet type specifically called Ever Clutch and the PTO clutch is of dry, single plate type. The traveling clutch is operated with the clutch pedal, whereas the PTO clutch is controlled with the PTO clutch lever.
- There is a single plate dry clutch located in the normal clutch housing this is only the PTO clutch, and is activated with the lever located to the left of the seat.
- The traveling clutch, referred to as Ever Clutch is located in the transmission housing and consists of multiple clutch packs for both forward and reverse. This clutch is operated via hydraulic pressure from a control valve assembly mounted on the left side of the transmission housing.
Ever Clutch in more detail
No one can say what Kubota engineers were thinking when they created this clutch system, however, I find it suspicious that the Hydraulic Shuttle system with the single dry clutch (HDT) appears to be almost identical to the Ever Clutch system (HDT-W). And I dont know if there was any model year order to these being available, but it seems almost like one day one of the engineers said: ya know - why dont we use the hydraulic shuttle system as the main clutch and use the dry clutch for the PTO. They would have then created a new control mechanism, probably beefed up the clutch packs a little and there you have it? or, possibly it could have gone the other way after experiencing difficulty with the Ever Clutch.
The Ever clutch itself (again we are talking inside the transmission here) is similar to the clutch packs found inside an automatic automotive transmission. It consists of a round metal housing that has a forward side and a reverse side (see attached pics). The forward side consists of 5 forward clutch discs and 5 metal plates and the reverse side consists of 5 clutch discs and 5 metal plates (see pics). There is a forward gear and a reverse gear located at either end of the respective clutch packs.
This is very difficult to explain in words But basically the metal discs are held to the metal clutch case/housing via 6 tabs on the OD of the metal disks allowing them to slide in and out. There is a clutch disc in between each metal disc and the clutch discs are splined on the ID and attached to the metal gear on the end of the clutch pack they can also slide. So basically the gear and clutch housing can rotate independently until there is pressure applied to the clutch pack which ties the gear and housing together. Got it..?
The pressure to the clutch packs comes from a piston in the center of the housing. There is a forward one and reverse one that push out from the center toward either end. These pistons are pushed out by hydraulic pressure pushed in between the piston and the center of the clutch housing. When there is no hydraulic pressure the piston is held inward away from the clutch packs with a spring.
Hydraulic pressure comes from a hydraulic control box mounted on the left of the transmission under the left foot rest. The control box is fairly simple in concept provide pressurized hydraulic fluid to the forward clutch pack or rear clutch pack as well as the lubrication/cooling passage. In design this control box is quite complex due to having to regulate the hydraulic pressure for smooth clutching and shuttle take off.
- The control box has three outputs Forward, Reverse, Lubrication. There is always fluid traveling though the lubrication passage to keep the clutch cool. The forward or reverse passages only get fluid pressure when the clutch is engaged to forward or reverse. In neutral and/or with the clutch pressed in all of the available fluid pressure is diverted into the Lubrication passage.
The shuttle control lever operates a diverter valve within the hydraulic control box. There are three positions.
- Neutral: Pressurized hydraulic fluid is sent to the lubricating port. No fluid pressure is sent to the forward or reverse ports.
- Forward: Pressurized hydraulic fluid is sent to the forward piston within the clutch via the forward port. A pressure regulating valve allows some fluid to continue to flow through the lubricating port.
- Reverse: Pressurized hydraulic fluid is sent to the reverse piston within the clutch via the reverse port. A pressure regulating valve allows some fluid to continue to flow through the lubricating port.
The clutch peddle actuates what is called the inching rod. The inching rod is a modulating type valve which, as the clutch pedal is pressed, opens a bypass port and allows the hydraulic pressure going to either the forward or reverse ports to escape back to the lubrication port. When its completely pressed and the inching rod is pulled all the way out (open) the hydraulic pressure is routed completely to the lubricating port.
For purposes of diagnosing the dragging clutch on my tractor its important to understand that the Ever Clutch is only engaged by hydraulic pressure. This means that with the engine off the rear wheels are free to rotate even with the gearbox in gear. This leads us to a simple test as pointed out by Dick on this forum: by jacking up 1 rear wheel (open differential) with the engine off and the parking brake not engaged, that wheel should be free to rotate with the gear box engaged.
- This was done on my tractor and resulted with the wheel being difficult to turn when in gear (not impossible, but difficult). And alternatively, easy to rotate with the gearbox out of gear.
- Also, with the engine running and the clutch or Shuttle shift in neutral the raised rear wheel spins in reverse.
This tells me that the dragging clutch is not a problem with the hydraulic control unit, but rather a mechanical problem inside of the Ever Clutch itself. Having studied the schematics of the ever clutch, I can only see two mechanical reasons that the clutch wont disengage.
1) The spring that keeps the engaging piston off of the clutch packs has broken causing the clutch pack to remain in gear.
2) The piston itself has seized or is somehow stuck and cant travel away from the clutch packs.
With that, I am ordering the clutch packs and spring kits this week. Depending on their lead time, I am planning to split the tractor toward the end of this week or this weekend. My intention is to take pictures and document the project and post the information as I go.
Any last minute words of wisdom or advice is more than welcome!
Clint
I have since spoken with a number of dealerships/parts places, scoured the internet for information, and spent days studying the service manual. What has resulted is a growing knowledge of the Ever clutch / hydraulic shuttle system found in the L4350, L4850 and L5450. (There was also a wet clutch version in the L2650, L2950, L3450, and L3650 how close it was related, I dont know)
I am completely baffled in the lack of information and understanding of this system particularly from many dealers a few of which had never heard the term Ever Clutch. I will say however that the staff at Messicks has been unbelievably helpful in providing information.
Anyway, I am starting this thread to cast the information that I have obtained out into the world. In my current situation, I will be splitting my tractor and replacing/rebuilding the Ever Clutch. I am planning to continue to post my findings in this thread along with any helpful advice or pictures as I go through this process.
Here is the overview of the systems as I know it:
The L4350, L4850, were offered in 3 different clutch/transmission arrangements. The L5450 offered only the dry dual clutch and Ever Clutch.
L4350, L4850, L5450 Model designation: MDT (Manual shuttle, dual traction = 4x4)
- From the service manual: the manual shuttle type tractor is equipped with a dry type dual-stage clutch. Operating the PTO clutch pedal, the traveling clutch and the PTO are turned on and off one after the other
- This clutch system has two clutch disks one right after the other within the clutch housing. One clutch is the traveling clutch the other is the PTO clutch.
- The shuttle system is manually operated
L4350, L4850 Model designation: HDT (Hydraulic shuttle, dual traction)
- From the service manual: The hydraulic shuttle type tractor, on the other hand, is provided with a dry type, single-plate clutch. With the clutch pedal pushed down and released, the traveling clutch and PTO clutch are turned on and off at the same time.
- This clutch system has only one dry clutch that operates both the PTO and traveling (they are not independent)
- The Hydraulic shuttle system incorporates a separate forward and reverse wet clutch pack within the transmission that allows the tractor to be operated with only the shift lever on the column. This clutch pack is operated via hydraulic pressure through a control valve assembly mounted on the right side of the transmission. (** this is important because the Ever Clutch is virtually identical, however is operated with a different control valve assembly mounted on the left side **).
L4350, L4850, L5450 Model Designation: HDT-W (Hydraulic shuttle, dual traction, wet clutch = Ever Clutch)
- From the service manual: On the Ever Clutch type tractor, the drive train clutch is a hydraulically actuated wet type specifically called Ever Clutch and the PTO clutch is of dry, single plate type. The traveling clutch is operated with the clutch pedal, whereas the PTO clutch is controlled with the PTO clutch lever.
- There is a single plate dry clutch located in the normal clutch housing this is only the PTO clutch, and is activated with the lever located to the left of the seat.
- The traveling clutch, referred to as Ever Clutch is located in the transmission housing and consists of multiple clutch packs for both forward and reverse. This clutch is operated via hydraulic pressure from a control valve assembly mounted on the left side of the transmission housing.
Ever Clutch in more detail
No one can say what Kubota engineers were thinking when they created this clutch system, however, I find it suspicious that the Hydraulic Shuttle system with the single dry clutch (HDT) appears to be almost identical to the Ever Clutch system (HDT-W). And I dont know if there was any model year order to these being available, but it seems almost like one day one of the engineers said: ya know - why dont we use the hydraulic shuttle system as the main clutch and use the dry clutch for the PTO. They would have then created a new control mechanism, probably beefed up the clutch packs a little and there you have it? or, possibly it could have gone the other way after experiencing difficulty with the Ever Clutch.
The Ever clutch itself (again we are talking inside the transmission here) is similar to the clutch packs found inside an automatic automotive transmission. It consists of a round metal housing that has a forward side and a reverse side (see attached pics). The forward side consists of 5 forward clutch discs and 5 metal plates and the reverse side consists of 5 clutch discs and 5 metal plates (see pics). There is a forward gear and a reverse gear located at either end of the respective clutch packs.
This is very difficult to explain in words But basically the metal discs are held to the metal clutch case/housing via 6 tabs on the OD of the metal disks allowing them to slide in and out. There is a clutch disc in between each metal disc and the clutch discs are splined on the ID and attached to the metal gear on the end of the clutch pack they can also slide. So basically the gear and clutch housing can rotate independently until there is pressure applied to the clutch pack which ties the gear and housing together. Got it..?
The pressure to the clutch packs comes from a piston in the center of the housing. There is a forward one and reverse one that push out from the center toward either end. These pistons are pushed out by hydraulic pressure pushed in between the piston and the center of the clutch housing. When there is no hydraulic pressure the piston is held inward away from the clutch packs with a spring.
Hydraulic pressure comes from a hydraulic control box mounted on the left of the transmission under the left foot rest. The control box is fairly simple in concept provide pressurized hydraulic fluid to the forward clutch pack or rear clutch pack as well as the lubrication/cooling passage. In design this control box is quite complex due to having to regulate the hydraulic pressure for smooth clutching and shuttle take off.
- The control box has three outputs Forward, Reverse, Lubrication. There is always fluid traveling though the lubrication passage to keep the clutch cool. The forward or reverse passages only get fluid pressure when the clutch is engaged to forward or reverse. In neutral and/or with the clutch pressed in all of the available fluid pressure is diverted into the Lubrication passage.
The shuttle control lever operates a diverter valve within the hydraulic control box. There are three positions.
- Neutral: Pressurized hydraulic fluid is sent to the lubricating port. No fluid pressure is sent to the forward or reverse ports.
- Forward: Pressurized hydraulic fluid is sent to the forward piston within the clutch via the forward port. A pressure regulating valve allows some fluid to continue to flow through the lubricating port.
- Reverse: Pressurized hydraulic fluid is sent to the reverse piston within the clutch via the reverse port. A pressure regulating valve allows some fluid to continue to flow through the lubricating port.
The clutch peddle actuates what is called the inching rod. The inching rod is a modulating type valve which, as the clutch pedal is pressed, opens a bypass port and allows the hydraulic pressure going to either the forward or reverse ports to escape back to the lubrication port. When its completely pressed and the inching rod is pulled all the way out (open) the hydraulic pressure is routed completely to the lubricating port.
For purposes of diagnosing the dragging clutch on my tractor its important to understand that the Ever Clutch is only engaged by hydraulic pressure. This means that with the engine off the rear wheels are free to rotate even with the gearbox in gear. This leads us to a simple test as pointed out by Dick on this forum: by jacking up 1 rear wheel (open differential) with the engine off and the parking brake not engaged, that wheel should be free to rotate with the gear box engaged.
- This was done on my tractor and resulted with the wheel being difficult to turn when in gear (not impossible, but difficult). And alternatively, easy to rotate with the gearbox out of gear.
- Also, with the engine running and the clutch or Shuttle shift in neutral the raised rear wheel spins in reverse.
This tells me that the dragging clutch is not a problem with the hydraulic control unit, but rather a mechanical problem inside of the Ever Clutch itself. Having studied the schematics of the ever clutch, I can only see two mechanical reasons that the clutch wont disengage.
1) The spring that keeps the engaging piston off of the clutch packs has broken causing the clutch pack to remain in gear.
2) The piston itself has seized or is somehow stuck and cant travel away from the clutch packs.
With that, I am ordering the clutch packs and spring kits this week. Depending on their lead time, I am planning to split the tractor toward the end of this week or this weekend. My intention is to take pictures and document the project and post the information as I go.
Any last minute words of wisdom or advice is more than welcome!
Clint