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  1. #1
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    Kubota L4850

    Default Ever Clutch Follow up

    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
    Attached Thumbnails Attached Thumbnails -ever-clutch-housing-jpg   -ever-clutch-trans-jpg  

  2. #2
    Veteran Member rbargeron's Avatar
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    Default Re: Ever Clutch Follow up

    Clint - You have provided TBN with an excellent description of the EverClutch system which will stand as a great resource to other users. Reading down through it, I have a couple observations / responses to points discussed.

    First, I think the reason very few dealers know anything about them is that comparatively few of these tractors were sold. At the time, they were slightly more expensive than Deere and Ford models of the same power. Also, during those years, kubota did not offer the whole product line through all dealers. I believe these high-end L3 models were only promoted by the bigger dealers. If you throw in the fact that the EverClutch had a very low incidence of failure, any one dealer's experience fixing them is likely limited.

    Regarding the time line of the products, the hydraulic shuttle came first, being offered in the L355ss and the earlier L3 series. Compared side-by-side the functions are the same but the clutch packs are not identical. The HDT-W EverClutch discs and plates are larger (different part numbers than those for the HDT. I think the engineers realized the hydraulic shuttle had proven itself in the field and with some scaling up in power capacity and the addition of more sophisticated progressive valving it could become the main and only clutch system for these machines.

    The multiple-disc hydraulically compressed stack is an often-seen design in automatic transmissions.

    Now to your specific tractor, with one tire lifted does the wheel start going backward immediately on switching on the starter? If so that looks like a mechanical problem in the reverse clutch pack. But if it only starts turning backward a few seconds later, after the engine has started and hydraulic oil is flowing, then I think the problem could still be in the control unit (or its linkage).

    If it is a mechanical issue, here's a possibility. The clutch disc facings are quite thin and a possible failure mode might be partial delamination of the facing. That could perhaps leave roughness or high points that could drag. The problem could conceivably be quite localized on one disc. There are 10 clutch discs in there (at $30 each) - so you might want to order parts after you've seen the guts.

    I wish you all the best in this repair - very few people have the courage to dive this deep. If you'd like someone to come hold the light let me know. If you have a flat floor and two rolling floor jacks, splitting it should be reasonable. Take care, Dick B
    L5450, L48, L3250, L345, never enough attachments

  3. #3
    Veteran Member brain55's Avatar
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    Default Re: Ever Clutch Follow up

    The clutch will also drag if the discs are warped typically from overheating. I have seen them warped to the point that when you put the machine in the opposite direction of which side the discs are warped the machine would actually lock up.

    The inching pedal should be used only for that purpose, not as a clutch pedal. With a little practice one can use the shuttle shift very effectively without even needing to use the inching pedal. The inching pedal also only meters while letting out the pedal, not while pushing it down.

    It is all coming back to me now. Originally these machines came with a pedal that looked more like a throttle pedal with very little throw, and if I remember correctly kubota came out with a pedal mechanism that looked and felt more like the traditional cluth pedal with much more throw.

    We didn't sell many of them, but I do remember having to reteach the owners how to operate them. And I do remember having to repair some of the clutch packs from the discs warping.

    Brian

  4. #4
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    Default Re: Ever Clutch Follow up

    That's actually great information Brian... There may be a key piece of information that I neglected to mention; when I first started to diagnose the dragging clutch, the first thing I did was check and adjust the clutch pedal and shuttle linkages. I did notice that the clutch pedal did not allow the inching rod to return completely. It was not far off...and by mechanical clutch standards would not likely have been more than the free play in the system, but maybe the hydraulic control is more sensitive.

    Also, I believe that the previous owner primarily used the backhoe and didn't have far to travel. I can't say for sure, but I have this gut feeling that the gear box on the machine was never put in neutral. Instead, once the clutch started catching a little, I think it was easier just to use the shuttle.... this of course would have created a lot of heat in the E.C. and if it wasn't warped discs to begin with, I'll bet it surely is now. We'll find out shortly!

    Clint

  5. #5
    Veteran Member rbargeron's Avatar
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    Default Re: Ever Clutch Follow up

    Quote Originally Posted by clinter36 View Post
    ......There may be a key piece of information that I neglected to mention...... I did notice that the clutch pedal did not allow the inching rod to return completely..........
    Just a thought - with the rear wheels both jacked up, shuttle in neutral, tractor idling in gear and in 2wd, wheel(s) slowly turning backward, does adjusting the inching rod affect it?

    How much drag is there? Can the wheels be stopped easily with the foot brake? Does it drag enough to change the engine sound when the brakes are on?
    Last edited by rbargeron; 04-13-2010 at 09:56 AM.
    L5450, L48, L3250, L345, never enough attachments

  6. #6
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    Default Re: Ever Clutch Follow up

    I didn't jack up both tires, but with one tire up and rotating there is absolutely zero affect of pushing the clutch pedal in. I tried hard and fast, slow, pumping etc. It doesn't affect the rotation even slightly.

    I also tried playing with the shuttle lever to see if some adjustment would change that - but nothing.

    It does not take much brake pedal to stop the wheel from turning. With the tractor back on the ground when I put the shuttle in neutral or push the clutch in, the tractor stops moving - for the most part. If I am on really level ground it will creep backward.

    I ordered the clutch pack kit and spring/piston kit today. I am reasonably confident that this is a mechanical problem and most likely the warped plates...there is a consistency in the symptoms that is difficult to explain, but seems to fit well. As apposed to the piston sticking or the spring broken, which would seemingly be a little more sporadic.

    Now I am trying to figure out what else I need to inspect or replace while I have the thing apart - I don't want to do this again for a couple more years.

    Clint

  7. #7
    Veteran Member rbargeron's Avatar
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    Default Re: Ever Clutch Follow up

    Only reason to jack up both is safety - so it doesn't grab and jump off the jack. Sounds like it isn't rubbing that hard. The warped plate idea is looking more like what's doing this. I keep wondering if it could be a leaking gasket or o-ring in the control valve somewhere. But if it was pressurized oil leaking to the reverse clutch piston or not being fully vented it would maybe drag harder.

    I can't think of much else to do while you're in there - beyond cleaning out any dirt, grit, filings or other contamination. The pto clutch on that machine has probably not been used much - so unless it's stuck there's no reason to take it apart. If you don't unbolt the clutch the tractor should go back together without needing an alignment tool. It might be a good idea to replace the pto clutch release bearing. On these rigs it tends to rack up a lot of hours because the pto lever is left up for starting. Dick B
    Last edited by rbargeron; 04-13-2010 at 11:44 PM.
    L5450, L48, L3250, L345, never enough attachments

  8. #8
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    Default Re: Ever Clutch Follow up

    Finally got the tractor apart and Ever Clutch removed. I will try to take some better pictures when reassembling for a write up on splitting the tractor.

    Splitting the tractor was fairly straight forward and it came apart without too much trouble. Once the tractor was split, I removed the Ever cluch hydraulic control unit and a few brake linkages then unbolted the clutch housing (ever clutch housing) case and removed it with an engine hoist.

    Its amazing how great of condition the gears and bearings seem to be in.

    Take a look at the close up picture of the Ever Clutch. You can see the warped and discolored plates on the left this is the side that is dragging. I am hoping to disassemble this EC unit further this afternoon and get the new plates and clutch discs ordered.
    Attached Thumbnails Attached Thumbnails -100_2607-jpg   -100_2606-jpg   -100_2597-jpg   -100_2603-jpg  

  9. #9
    Veteran Member rbargeron's Avatar
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    Default Re: Ever Clutch Follow up

    Great pictures - wearing parts are pretty far gone on that side. Any theory about how they got that way? Seems like if an operator was riding the clutch pedal all the time, it would be the forward-direction pack that would get burned out first.

    You mentioned finding that the inching-rod travel was being restricted by the clutch pedal. Wouldn't that affect both directions equally? I hope my comments are not a PITA - but if a cause isn't found this damage might happen again.
    L5450, L48, L3250, L345, never enough attachments

  10. #10
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    Default Re: Ever Clutch Follow up

    I have a L5450 with an Ever-Clutch. Tractor has 2500 hours and has started to become difficult to put into gear. Both gear selectors are equally difficult: High - Low, and 1-2-3-4. It was particularly difficult this winter on really cold days. It engages just fine. Do you guys have any advice for me on this?
    Thanks

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