Only shifting when hot? And even then, laggy? L2900 GST

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Hey all, so I've finally got my tractor reassembled and driving!

I flushed all the fluids on the Kubota, and replaced all the filters with genuine Kubota replacements.

Nonetheless, it only wants to shift when it's warm. And even then, it feels "laggy" inbetween gears. There's a delay that doesn't seem normal.

Any idea what the culprit might be?

L2900 with GST.


I'll try and update with a pic and vids in a few!
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,286
4,853
113
Sandpoint, ID
GST's are very picky about the pressures delivered to the system, and the type of fluid it's running with.

More information might help narrow down the exact problem.
Does it just not move when it's cold?
What happens when you go from forward to reverse?
When it's lagging does it have solid power?
 

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Wolfman, I flushed the old stuff (which looked pretty damn good, by the way) with somewhere around 11gallons of SuperUDT.

I'll check the hydraulic pressure i've got to see if it's within normal operating range... I'll post back as soon as I do so.

Thanks!
 

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Shaun,

I did OVERFILL it with my initial flush by a bit. I've since drained a bit and can finally see a bit of the bubble at the top of my fill glass. So looking at it on my level concrete garage floor, the system is perfectly full with Super UDT.

Since this is my first tractor, I can make a video tonight and post it to youtube. It'll have been sitting since yesterday, so it'll be "cold".

I could totally be doing something wrong and you guys can point it out...
 

ShaunRH

New member
Lifetime Member

Equipment
L3200
May 14, 2014
1,414
6
0
Atascadero, CA
Oil level should be halfway up the glass, not to the top (at least according to my L3200's manual). If it gets too full, you can end up with the oil making contact with items that just churn in air. If that happens the oil cannot hold even pressures and the air literally floods the system causing all kinds of problems. It should actually run better 'cold' in this condition than 'warm' so it's backwards of what you are experiencing but air does weird things in hydraulic systems.

I guess I don't know what a "GST" is, I was assuming it stood for "Gear Shift Transmission" but that shifting is a function of clutch and gear lever position so I'm not sure what the changing the oil would do to that setup. Now, if it's an HST, then that's all about hydraulics and the air or other factors come into play.
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,286
4,853
113
Sandpoint, ID
ShaunRH, GST is a Glide Shift transmission, simply put it's a geared transmission that is shifted by hydraulic mechanisms and a hydraulic clutch.
The shift forks are moved hydraulically, not with a shift lever.

Air is most likely not your problem.
How is the steering? Is it laggy or stiff?
 
Last edited:

ShaunRH

New member
Lifetime Member

Equipment
L3200
May 14, 2014
1,414
6
0
Atascadero, CA
Well, see, thar ya go. Helps to not assume one thing when he really meant GST not HST... LOL! :rolleyes:

Just ignore me... going over here to this corner and beat my head against this brick...

<thud><thud><thud>...
 

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Steering is just fine. I think I'm going to re-drain all of the hydraulic oil, and take the valve body off.

Anybody know what size/thread the valve body hydraulic pressure ports are? 1/8 NPT or 1/8 BSP?

I can see the valve body area looks "new". It's not the same color as the rest of the surrounding area, and i can see a rubber gasket peeking out. I think the PO tried something in there.....

 

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Okay folks, so here's a vid of my hydraulic fuid pressure within the tranny upon intial startup. The tractor has been sitting for about 2 days. About 80* outside. I'll start it up, and then put the trasmission in DRIVE, and then shuffle through a few gears.

http://youtu.be/aP_7cMC90DU

ZERO psi. Won't budge.
 

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
And here she is after about 25 minutes of warming up by idiling in the garage. We're finally showing 360 PSI consistently across the gear range, in FWD and REVERSE.

But you can see about 4 second delay while the transmission build pressure within the shifts.

https://www.youtube.com/watch?v=t2mIRhhqfh8
 

CaveCreekRay

Well-known member
Lifetime Member

Equipment
L3800 HST, KingKutter box scraper, KingKutter 66" rake, County Pride Subsoiler
Jul 11, 2014
2,631
93
48
Cave Creek, AZ
Don't know your tranny but...

Could there be a gear selector valve that ports pressure from PARK (zero) to any gear that has frozen closed? Whatever powers the clutch engagement is not getting ported pressure. I.E. your transmission is stuck in zero.

Back to the sidelines
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,286
4,853
113
Sandpoint, ID
Which port were you testing?
Input pressure from the pump
or clutch input?
Was the shuttle in forward or reverse when you tested?

Yes the ports are BST.
 
Last edited:

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Which port were you testing?
Input pressure from the pump
or clutch input?
Was the shuttle in forward or reverse when you tested?

Yes the ports are BST.
That video was taken at the clutch input port.
This morning did another "cold test" (i.e. tractor was sitting all night) on the GST transmission port which gets its pressure from the pump, and i was still at 0PSI until the better part of half an hour.

I'm going to move onto the right side of the engine and take a look at the regulator/relief valve.

I'll keep following the flow on the hydraulic diagram. I'll build a plug to islolate different parts of the flow pattern. .. I'll figure it out.

I'd do it today, but I'm on my way to pick up a bike ('79 Honda CBX1000), so excuse any spelling errors as I'm typing from my phone.

Have a great weekend!
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,286
4,853
113
Sandpoint, ID
DON'T PLUG ANYTHING! it's an open system and installing a plug is a BAD thing, it will drive pressures up and blow seals.

You answered exactly what I was looking for, you don't have a trans problem you have a regulator or pump problem, I leaning to a bad seal in the pump.
I would pull both the regulator and the pump and inspect them, Avoid pulling any part of the regulator apart as they do not sell individual parts for the regulator and a replacement for it is $411.54, it's not considered a rebuildable component.

If you don't see anything obvious, send the pump to be tested.

'79 Honda CBX1000, nice big old super bike, I had a friend that had one.
 

audi200TDI

New member

Equipment
Kubot L2900 GST
Jul 5, 2014
21
0
0
CT
Wolf, thanks for the continued imput on this thread! I see you're super active, and answer (or at least point people in the right direction) on most threads on this forum.

We've isolated the GST pressure from the reducing pressure, with a special banjo fitting that he built. As soon as the engine is started, 360PSI were present instantly at the reducing valve. As such, pressure was being lost somewhere within the GST.

After all of the pressure tests we've done thusfar, we anticipated that would be the circlip would be the likely culprit. My father contacted Kubota via EMAIL, and requested a copy of the TSB about the broken circlips on the clutch packs. They referred him to the N.E. Division Rep. One week after his request, he received a phone call from a rep that told him that the TSB is proprietary to Kubto and he cannot be e-mailed a copy. He recommended we we check the rotary valve, otherwise go visit our local dealer in Orange, CT.


Based on this, he decided to pull the valve body on the GST. I think the pics speak for themselves...






We called the dealer, and they said we COULD NOT purchase the ENTIRE CLUTCH PACK ASSY. and that we would have to purchase the parts within it individually.... which means I've got to split the tractor again to identify which specific parts need to be replaced.

So my question: After I split the tractor again, do I have to remove only the CLUTCH HOUSING CASE to have access to the GST clutch assembly, or do I have to remove the MID CASE as well?

From other threads I've read to try and diagnose this issue, I thought that Kubot had release a "new and improved" clutch pack assembly for the L2900DT-GST (serial# 52797)

Can anybody point me towards somewhere where I might find the entire clutch pack assembly? It seems like when these circlips go, they damage the groove within the aluminum housing. If that's the case, I'd rather replace the entire unit...


Based on my parts manual from the Kubota website, my GST clutch assembly should be TA040-61500.

But also in the book, from serial#54589 and UP, the clutch assembly part number changes to TA040-61502. Is this an UPGRADED design?

The dealer said this newer assembly would not fit in my particular tractor, and I'd have to buy the individual parts to fix this. Why are there two different assembly numbers for the different serial numbers within this model number tractor? Is the dealer just trying to "cover its ass" and sticking strictly to the parts book?

On Merrick's website, the TA040-61502 is listed as a REPLACEMENT for my 'older' TA040-61500.


Again, I would much rather buy the whole assembly and have the piece of mind knowing everything has been replaced.

Golden Eagle, Coleman Equipment, and Messik? Would those guys have any input? Would they carry the entire assembly?
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,286
4,853
113
Sandpoint, ID
Here is what I found.

It looks like the replacement clutch assembly for both the TA040-61500 and the TA040-61502 is a TA040-61507, the odd part is both the 500 and 502 are 589.45(that is if they actually do still sell it) and the price of the 507 is $953.37 (Golden Eagle) $958.14 (Messick's), huge increase for the same parts, but my Hydralic clutch assembly runs $948.01 so about the same price.

What I'm not 100% sure is that it is a true replacement, maybe a phone call to either might give you an exact answer.

I'm with you I would rather buy the whole assembly then individual parts.