L2900D with a (very) slow engaging GST

[Spectramac]

I didn't take enough banjo fittings apart to get any turned around.

I wish I'd heard about the oil 'before' I changed it. I put in Napa's tractor hydraulic in the yellow buckets. I haven't taken the valve off the pump yet cuz it's pretty busy in there. I wonder if it can be the problem if the pressure is good enough at the check port? I can here a slight buzz from it sometimes as it trys to go into gear...

I am leaning towards a problem with the valve body because the pressure is fine everywhere until I get to the clutch port. It says in that writeup to check the modulate check and modulating valve, but doesn't say where they are?

 

[KennyV]

What is the temperature of the air where this tractor is located... If it is below freezing, your choice of oil will have an impact on the GST shift and clutch engagement...(Only until it warms up)
If it is above freezing now, it will not ... My GST (along with many thousands of other GST's are and have been functioning perfectly with straight weight hydraulic oils... UDT & it's equivalent has millions of hours in these systems...
You are having a mechanical problem... NOT a chemical or viscosity problem. KennyV

 

[Spectramac]

We're in Washington state, been a cold wet summer so far but we're starting to see some 70 plus degree days. I agree we have something hanging up, just wish I could figure out what.

 

[KennyV]

We have had a record breaking number of days Over 100 degrees & Very dry... It was 114 today & I had to replace my water heater, Nice day to have no water for a shower...KennyV

 

[Spectramac]

I don't know where else to look at this thing. I wish I could just push it off a cliff, cuz it wouldn't want to drive off it!

 

[Spectramac]

Well, after a pep talk from the local dealer it sounds like the 2 valves in question are the two that go up from the bottom of the valve body. I pulled them both out and (of course) can't find anything wrong with them.

I'm seeing some foam on my gauge when I take the hose off and wonder if the anti-foaming properties of the cheaper oil might be an issue? I hate to buy more oil, but I may have to if I can't find anything else.

 

[Spectramac]

Ok, I changed the oil and it worked for almost 5 minutes, but now the clutch pressure is hanging up right at 60 psi instead of going on around to 375... It does seem to be a lot more stable now, with the old oil you never knew what it was going to do. I was almost ready to call it fixed too.

Sure be nice to find an exploded diagram of the valve bank and see if there's anything I haven't seen yet.

 

[KennyV]

Was away from my scanner... sorry for the delay...
Here is the valving for the clutch...
KennyV

 

[KennyV]

And a couple more...
I'll look through the troubleshooting section to see if there is anything worth scanning... KennyV
OOPS ... didn't attach them..

 

[KennyV]

Try again... KennyV