226D Transmission Regulator Case Gasket Question

[HappyDaze]

Here痴 what I致e got:

Classic slipping in forward a little and mostly reverse. I致e read enough to know I知 hunting for an issue in the lower shift area and that痴 not my question.

I removed the old gasket, ordered a replacement, put it on and it made no real difference. Took it off again and I realized the old gasket and the new were completely different. The old one seems like it is a proper mate for the transmission where it bolts on, but has nothing similar to the ridges on the mating surface of the regulator case. The replacement gasket has all the right ridges in all the right places for the regulator case but only the bolt holes line up and the outer shape of the piece seems correct but it痴 different.

The old one appeared to be the problem, as it showed signs of compromise throughout. The old one also appears to be the same one in the drawing in my service manual. But it痴 different. Hopefully photos attach here...I知 not a real mechanic but I致e played one in my garage/back yard for decades and I don稚 know where to start.

Has the regulator case been swapped out? Did they just update the gasket...?

 

[winston1]

Looks like the gasket is fine to me. If the problem didn't change maybe you are looking in the wrong place. Are we sure the clutch is not slipping? Does it slip mostly in higher gear or lower gear?

 

[HappyDaze]

Thank you for the quick reply. The gasket is new but see the one that was on it is different. That is part of my question, the different gasket configurations. Can they both be the right one, just an updated model...?

It mainly slips in reverse. When it does slip in reverse, to the point it stops, the pto continues turning. That痴 without a load as I have no pto driven implements at the moment. I feel like the mechanical clutch is operating properly. However it has been run for the last 20 years with the clutch pedal only allowed about 3/4 of its normal travel as the last 1/4 has been obstructed by a fabbed/flubbed aftermarket fel bracket running perpendicular to and directly in the path of the pedals. Clutch and brakes. It痴 kind of fun getting a dirty hands education of the inner workings of this thing. It blows my mind to think how did they think to do this in the first place.

Anyway... see the one in my service manual matches the one that was on the tractor but compare it to the new green one that came from Hoyer. Then even stranger is that the new one actually matches the regulator case but the old one seems to match the transmission case.

 

[AaronM]

I don't know why the design changed. Maybe to apply more sealing force just along the ridges where it is needed? There must be a reason though because the new gasket would be considerably harder to make. I do know that gasket has been like the one we sent for a very long time and I have not ever heard of any problems. I do not think that is going to be your problem.

EDIT: I made a new TBN account to keep my personal farm stuff separate from the parts business stuff and forgot to log back in as HoyeTractor. Just in case anyone is wondering why I posted under this new name.

 

[winston1]

Okay, if you rule out the clutch what about the springs and relief valves in the regulator case? Have you checked them for broken springs or trash in them?

 

[California]

Does anyone know if there are test ports on a PowerShift transmission to see if full pressure is arriving at various circuits?

 

[HappyDaze]

I do not think that is going to be your problem.

Even with the condition of the gasket I removed?

 

[HappyDaze]

Have you checked them for broken springs or trash in them?

None were broken but the outer one was slightly shorter than spec. My calipers are pretty beat up but there’s where they stand. Is being even a hair short enough to make it slip?

 

[HappyDaze]

Another couple questions regarding the gasket...

Do I need to use a gasket sealer?
If so, which one and does it get applied on one side of the gasket or both

What is the correct order to tighten the regulator case? Seems like I would start in the middle and then alternate between opposite sides around the outer then follow it again with the torque wrench...?

 

[HappyDaze]

Bottom so it is only pushed in roughly 3/4 of the way down with your foot on it.

 

[normde2001]

' the clutch pedal only allowed about 3/4 of its normal travel as the last 1/4 has been obstructed"

Tell us about this. Which end of clutch pedal travel is obstructed? If the top end it has to be slipping.

 

[winston1]

Does anyone know if there are test ports on a PowerShift transmission to see if full pressure is arriving at various circuits?

Yes, there are test ports, at least on his 226D. Page 250-10-21 gives the procedure. Assuming HappyDaze has a manual based on his spring length information.

Since the manual gives no information about sealant I would not use any, if I did it would be a very light dose. You don't need any sealant getting in all those passages.


Do you have any freeplay at the top of the clutch pedal?

 

[rScotty]

I must have missed the beginning. Can someone explain again why the regulator case is taken apart in the first place? Was it leaking?

What were the original symptoms? And most importantly, what were the original internal clutch pack pressures from the test ports? And what are they now?
How does the manual clutch fee play even enter into this kind of problem?
Sorry to be so dense, am I just asking all the wrong questions?
Confused, rScotty

 

[winston1]

May need to read from post #1. HappyDaze thought the cover might be where his problem was. He has not done a pressure test. His tractor would quit moving, I suggested it could possibly be the clutch.

 

[HappyDaze]

It is/was slipping, most noted in reverse. Slow engaging in forward gears too but they engage eventually whereas in reverse it is happy to slip in all ranges. It will engage in reverse eventually in range 1, without a load.

SOLVED FOR NOW:
And here is something that seems to happen often in these 菟owershift slipping threads...I realized I had ignored the inertia brake adjustment but not much has been said about it so I didn稚 think too much about it.

It needed plenty of adjusting (see pics). Once I loosened the clutch pedal adjustment nuts and went through the motions of adjusting the clutch pedal freeplay (the manual says adjust the clutch first but it was already pretty much set correctly) then I made the correct adjustment to the inertia brake and now it (the transmission) works like it痴 supposed to. It痴 fine now. I don稚 really get it but I知 guessing it has something to do with the clutch pedal travel being limited on the down end?

Either way I知 going to remove the loader and the corrupted brackets and locate a proper mounting bracket that does not obstruct the pedals.

What does the inertia brake do? Could it have been the problem or is this like Clark Griswold痴 Christmas lights, as in did I do something else I didn稚 realize in the process and the inertia brake was just coincidental...?

 

[HappyDaze]

Here are photos of the adjustment that was made to the inertia brake:

Left one is before the adjustment and the right one is after FYI

 

[winston1]

Glad you are up and running. Only my opinion, I believe the inertia brake function is to slow down or stop the powershift clutches when the main clutch is depressed. Anyone know any different I would like to know. I sure have no idea why out of adjustment caused your tractor not to pull.

 

[rScotty]

Glad you are up and running. Only my opinion, I believe the inertia brake function is to slow down or stop the powershift clutches when the main clutch is depressed. Anyone know any different I would like to know. I sure have no idea why out of adjustment caused your tractor not to pull.

I don't know anything at all about the inertia brake. It's a real hole in my Yanmar knowledge. I've never worked on one and not sure I've even seen one. And I don't even know the how and why of the inertia brake adjustment as it interacts with the rest of the powershift tranny. The inertia brake gets scant coverage in what is otherwise a pretty good workshop manual. I'd sure like to know more about it if anyone has info.

In general, problems with powershift are rare. When there is a problem with powershift the first thing to do is to clean out the reusable lower hydraulic filter, replace the screw-on throwaway hydraulic filter, and put in new hydraulic oil. Lots of times that is all it takes - especially cleaning that lower reusable filter. If that doesn't help, the next step is to get a workshop manual and some inexpensive pressure gauges so that you can take pressure readings at the test ports on the regulator case cover. Doing that will pretty much tell you what's next.

If you need to go deeper than that, you also need to be a pretty good mechanic with a real Yanmar workshop manual and a clean place to work. And I expect that once you get done you are going to know more about powershift than I remember anyway. It's been a while ago for me.
Good Luck!
rScotty

 

[California]

...I believe the inertia brake function is to slow down or stop the powershift clutches when the main clutch is depressed. Anyone know any different I would like to know.

I didn't know there was anything adjustable as shown in HappyDaze's photos. But I wonder if this is related to a 'parking brake' effect I noticed in both of the YM186D's I have experience with. The later one has a noticeable braking force in neutral if I stop for something on mildly sloping plowed ground, enough braking that I don't need the manual brake lock. This effect is stronger than on the previous YM186D but that one had it to a noticeable degree. And starting off cold in the morning, either tractor has some feeling that it needs to warm up before brakes release. I thought I read somewhere that shifting the Powershift to neutral, routes fluid to two gears at once to provide a braking effect.

Does anyone know more about this?