NEW YM336D PROBLEM

[careyo63]

With no mention of any Debris in the Pan. Metal,Clutch material would be a good sign the problem was in the Valve body. I would clean everthing up. New correct Fluid, Filter, Cleaned Pickup screen and button it back up and see what happens. If it still does it your probly be going to Splitsville. I use to work in the evenings in a friends/roomates Transmission shop that worked on all all types. Learned alot and seen alot. Esp. what not to do.

 

[California]

is this the first power shift problem we have seen on here where it could possibly something inside the transmission?

I dont recall seeing anything more than low fluid, wrong fluid, or plugged screen or filter.

There have been some instances over several years where the symptoms were similar to a slipping conventional clutch, and Norm's advice to replace that broken pressure relief spring was the answer. I assume the line pressure is what binds or releases clutch packs identical to those inside an automotive A/T.

I don't recall any threads where problems inside a PS were more severe than this (or dirty screens etc).


This is what a severely dirty screen looks like. But this was in the manual-transmission YM240. The screen disintegrated while removing it so I had to replace it. That much debris didn't seem to hurt anything. The hydraulic system still works fine 10 years later.

 

[winston1]

I recall one thread with a broken clutch shaft. I guess anything is possible, well, most anything. Talking about clutch pack shaft.

 

[grainger12002]

RB Do you a field to mow ? Is it smooth enough to run in hi range ? Mine the ground speed is just too fast to brush hog with in ho range, my 336d has 4 forward speeds (range) and three plus reverse on the power shift

 

[normde2001]

is this the first power shift problem we have seen on here where it could possibly something inside the transmission?

I dont recall seeing anything more than low fluid, wrong fluid, or plugged screen or filter.

In my 13 years of following Yanmar forums powershift probs have never been anything worse than those broken springs, but obviously that is not the case here.

 

[R Barger]

RB Do you a field to mow ? Is it smooth enough to run in hi range ? Mine the ground speed is just too fast to brush hog with in ho range, my 336d has 4 forward speeds (range) and three plus reverse on the power shift

No I mow in 3rd range and 3rd on the powershift. As I said before it seems like low oil pressure getting to the clutch pack. Waiting on a gasket from Hoye. Going to put it back together and keep my fingers crossed. Winston,Did I understand you right that the valve under the valve body control that pressure?

 

[kenmac]

I should know this ,but doesn't the powershift have it's own pump ? If so could that be the problem ? I have to admit, I don't know as much as I should about my tractor. I've never had any problems with mine

 

[R Barger]

I should know this ,but doesn't the powershift have it's own pump ? If so could that be the problem ? I have to admit, I don't know as much as I should about my tractor. I've never had any problems with mine

Yes the powershift does have it's own pump. When I put it back together I'm going to try to check the pressure if I can figure it out. When I first started having the problem it would come and go. This made me think it was something like a valve. I have a YM2002D I have owned for over 10yrs and all I have done to it is replace the front tires and change the oil every year so I'm spoiled to not having to work on Yanmar's.

 

[winston1]

No I mow in 3rd range and 3rd on the powershift. As I said before it seems like low oil pressure getting to the clutch pack. Waiting on a gasket from Hoye. Going to put it back together and keep my fingers crossed. Winston,Did I understand you right that the valve under the valve body control that pressure?

My statement was unclear so let me clear it up. That second relief valve under the valve body controls lubricating oil pressure to the clutch packs. The main relief valve controls operating pressure to the clutch packs.

Kenmac is correct, the powershift does have it's own pump and I would say that is a possible but very unlikely cause of the problem.

No drawings or anything on the 336 but am confident it has ports for checking both operating and lubricating pressures. Your manual should locate them and tell you what pressure to expect.

 

[R Barger]

My statement was unclear so let me clear it up. That second relief valve under the valve body controls lubricating oil pressure to the clutch packs. The main relief valve controls operating pressure to the clutch packs.

Kenmac is correct, the powershift does have it's own pump and I would say that is a possible but very unlikely cause of the problem.

No drawings or anything on the 336 but am confident it has ports for checking both operating and lubricating pressures. Your manual should locate them and tell you what pressure to expect.

The bad thing is my manual is missing to trouble shooting section on the powershift. It does have the complete tear down and reassembly. No specs like pressures. The valve body has 2 ports that are most likely for testing.

 

[winston1]

The bad thing is my manual is missing to trouble shooting section on the powershift. It does have the complete tear down and reassembly. No specs like pressures. The valve body has 2 ports that are most likely for testing.

Interesting, most manuals I am familiar with have a repair section toward the front of the manuals and then toward the rear it has an operation and test section on the different components. That is the section that information would be in.

For what it is worth the 226 operating pressure is to run 213 to 227psi at 104-122F with range shift in neutral and power shift in R,1,2, and 3.

Same temperature fluid the 226 lubricating pressure is to run 5.4 to 6psi with range shift in neutral and power shift in R,1,2, and 3.

 

[R Barger]

Interesting, most manuals I am familiar with have a repair section toward the front of the manuals and then toward the rear it has an operation and test section on the different components. That is the section that information would be in.

For what it is worth the 226 operating pressure is to run 213 to 227psi at 104-122F with range shift in neutral and power shift in R,1,2, and 3.

Same temperature fluid the 226 lubricating pressure is to run 5.4 to 6psi with range shift in neutral and power shift in R,1,2, and 3.

Thanks again for the info. Maybe the gasket will be here tomorrow. I'll update you then.

 

[R Barger]

The bad news is 3days and $24.00 to get a gasket and I didn't expect it to help anything but the good news is the tractor works fine. I haven't worked it under a load yet but it feels solid even in the highest gear. Before it wouldn't even pull itself up the slightest grade. At first I thought it had effected the power till I saw I had the parking brake on.The valve must have been sticking. Thanks for all the thoughts and ideas.This forum is a powerful resourse.

 

[normde2001]

A sticking relief valve is not uncommon, although they are usually pretty obvious once you get into them.

 

[R Barger]

Thanks again for the info. Maybe the gasket will be here tomorrow. I'll update you then.

Winston, Like I said earlier my repair manual is photo copied one and who ever made it left out 75% of the testing section in the rear. That will be hard to locate just that part. Might have to get another manual.Your input was a great help.

 

[kenmac]

Is the 336 manual ? If so I have A 336 service manual. Let me know what pages you need and I'll see if I can copy them

 

[grainger12002]

there was also mention of a website where you could download manuals for yanmar, and yes this is a great group, glad you are progressing with the 336 !!

 

[Melenka]

I have a 336d and have problems with powershift. When tractor oil is cold works fine as oil heats up pressure in 2 & 3 power shift drops to 60 psi, first and reverse at 215 psi hot or cold, can you help solve the problem.

 

[normde2001]

Read the thread.