Help Needed-GST transmission question

[tamu94]

I posted earlier regarding my GST transmission temperature. I noticed last week it was very hot after using my PTO and yesterday I noted the same thing. I am concerned the PTO clutch is slipping and causing the problem as the PTO spline heats up first. Everything seems to run fine and the transmission fluid is normal.

For everyone with a GST transmission do you see the same thing when using your tractor? Is this normal or should I call the dealer?

 

[art]

Most transmissions run around 200 degree's with the hydraulics in todays systems.

 

[WAB85]

I read your earlier post, and of course this one. The temp's you are describing don't sound right to me.
I have an L3830 GST with just under 60 hours. I use a 6 ft. pull type KK mower (bush hog type) to mow some pasture, water-ways, and along crop fields. The other day I mowed at least 4 hours without stopping. When finished I always unhook the mower. I sure don't feel the kind of heat you are talking about.
I would have it checked out if it was mine.
KW

 

[Leejohn]

I had a L3010GST for 3 years and my trans seemed to run hot. It was like that from day one. I would say it was around 200 degrees like art said and that is hot when you touch it. My PTO shaft did just as yours does. I would say run it as long you have no loss of power. I got the L3130 HST after that and it didn't run as hot. I haven't checked my new L4240 yet.
Lee

 

[tamu94]

Thanks for relating your experiences. I will run it by the dealer just in case. I don't think anything is wrong but it is very different than my old 2350.

 

[_RaT_]

Like Art said, 200 degrees is normal. Next time check the temp. I'll bet your in that range. Thats hot to touch but for metal, thats barely warm.

 

[MichKubota]

I see this is old post but I don't understand why the GST would get so warm. The only thing the hydraulics do in the GST transmission is engage/disengage clutch and shift gears.

The hydraulic forces used to shift gears are temporary loads (only when shifting) and the load to engage clutch is minimal.

I would think the heat in transmission is due to the friction on the gears which even a non-hydraulic transmission will see.

I have GST and it doesn't get hot at all after over an hour. However, I am doing more loader work which has lots of stop/go/idle time.

 

[Yankee Clipper]

Tamu,

You could have a PTO pack issue (slipping) or more likely a slipping GST clutch. You did not say what his model was but the old GSTs (00/10 series/L35) did have an issue with the GST clutch cup. The cup would break in the root of the snap ring groove and the pack would slip or not correctly engage/disengage.

The recall program started in 1997 is long over - it lasted 7 years. Both parts and labor were paid on select machines for the first 5 years and parts only during the last 2 years.

The best thing is to take it to the dealer and have them run a pilot and clutch pressure test. Maybe drop the GST control valve to see if the GST clutch is out. A GST is not something the unitiated should attempt to handle. While not rocket science, you have to know what you are doing or you will get to do it twice, so I would again suggest to get the dealer to do the inspection and if necessary, the clutch overhaul.

Good luck!

 

[_RaT_]

Hot day, lots of loader use, lots of hydraulic fluid being pumped, it gets hot. Remember, the GST uses the same reservoir for hydraulic fluid as the hydraulic pump. Lots of pumping will warm the fluid. Just bypassing the pump on a hot day will warm the fluid.

I see this is old post but I don't understand why the GST would get so warm. The only thing the hydraulics do in the GST transmission is engage/disengage clutch and shift gears.

The hydraulic forces used to shift gears are temporary loads (only when shifting) and the load to engage clutch is minimal.

I would think the heat in transmission is due to the friction on the gears which even a non-hydraulic transmission will see.

I have GST and it doesn't get hot at all after over an hour. However, I am doing more loader work which has lots of stop/go/idle time.

 

[Yankee Clipper]

Most all tractors and all Kubotas use the transmission case for the reservoir for hydraulics as well as the splash lube for the transmission.

If the heat problem is what you are after, check to be sure the three point hitch is coming off high pressure - neutrallizing at the top of travel.

This is easy to do - with the engine dead and the hitch arms empty, grab one of the lower arms and lift it to the top of travel. Make a mark with a piece of chalk or magic marker on the arm and top cover - a straight horizontal line when you feel the bellcrank under the top cover hit the stop.

Then get on the tractor - start it and pull the position control handle fully back and see if the arms travel to the top. The mark you just made should not be lined up but should be offset / staggered. If the mark lines up, find the external linkage (on one side of the rockshaft externally) and extend the linkage until such time that the line is offset / staggered.

This means the position control valve is fully seated and neutralized. If it is not, the pump is constantly blowing the relief and that makes heat in the system.

If you want to verify the symptom, shorten the linkage and listen to the engine load up - when you lengthen it, you will hear the engine RPM change.

This also will make your loader not have as much power to lift with the hitch fully raised. Very common issue because people mess with the linkage to get more lift height. Just as easy to fix, if this is the source of the heat.

Good luck!

YC