GST shuttle shift and tractor rpms

[dannyk]

My owner's manual for my L39 with GST says to "Reduce engine speed to low idle before shifting the shuttle shift lever." Is this really necessary? If I have to use the throttle lever to go back to idle every time I change direction (forward to reverse and vice versa) and then I have to use the throttle lever again to increase rpms before moving, this would seem to be a very cumbersome transmission!

What am I missing here? Is the preferred technique for dirt work to keep the engine at idle and use the foot throttle?

I'm confused!

Danny

 

[DK35vince]

I would think foward/reversing at higher RPM's would be addition shock on the transmission and wear /tear on the clutch's.
Simply use the foot throttle for loader work. What to forward/reverse let off on throttle peddle, want to go push down on throttle peddle.

 

[art]

I hate not having a foot throttle for loader work! They are the best even on skid steers!

 

[DUMBDOG]

I use the clutch when going from forward to reverse, sometimes at 2000 rpm without a problem.

 

[dannyk]

OK, so I get the feeling that there are two methods for using the GST when doing a lot of forward-reverse movements.

One would be to keep the engine at idle and use the foot throttle as necessary.

The second would be to run at normal working rpm but use the clutch when shifting from forward to reverse (or reverse to forward) using the shuttle shift.

I'm wondering which of the two methods most people use and which method is most productive?

Danny

 

[Soundguy]

Bottom line.. even if you keep the engine speed up and use the clutch.. you will be getting more clutch wear... IE it will slip more...

I think leaving idle speed set and using the foot throttle for the variable speed control is probably an ideal way to let the powershifting style trans work best.. ( though i don't own one nor have i read their manual.. however.. the fact that your manual specified that.. and not leaving it running full tilt and using the clutch.. well.. lets just say that i feel that their engineers probably knew what they were doing when they wrote those specs.. )

Soundguy

 

[KennyV]

Soundguy is right on…
The foot clutch (dry clutch) will wear out much faster slipping the trans input. Use the foot throttle and the shuttle shift (wet clutches). The clutch is only generating heat, with limited air to dump the heat (dry clutch), it will burn itself up a lot faster than the wet clutch pack, this system has the entire hydraulic system to shed heat. This has been discussed at length within the past 6 months. As before, I still never use my foot clutch, ever. I cut the rpm and shift using GST or the shuttle shift, letting that actuate the hydraulic clutch pack. Much more efficient. (I drive my tractors like I never want to see the inside of the drive train)…
In your car or truck, you would never set a high rpm then move your gear selector from reverse to first and back to reverse… at least not many time$... KennyV

 

[Ben3130]

All this makes sense when talking about doing FEL work, but what about when running a rear pto implement? For example, what about when you are brush cutting and need to change directions? Granted, the amount of direction change is a LOT less than when doing FEL work, but I still don't want to idle down, shuttle shift, power up, back up, idle down, shuttle shift again, power back up, then resume mowing. It seems like that is also a lot of wear on the tractor. In this case would it not be better to just shift without changing your rpms? Some of my mowing is around obstacles where manueverability is less than optimal, so I end up having to shuttle shift at least once to change directions.

I don't mean to sound antagonistic, but I've started doing a fair amount of mowing for friends and relatives, and I don't want to be running the tractor in a way that will cause unnecessary wear and lead to earlier than expected failures.

 

[KennyV]

Ben…
When I am running my RFM at pto speed, and I need to reverse, I can easily slide my selector GST down through the gears, this slows forward momentum and I can shuttle to reverse and slide back up the gears to reach a speed in reverse that is easy to control what I’m doing, then back to forward and etc… all this happens very smoothly and never do I need to slip a dry clutch…
The main point may very well be, as you stated, while mowing you don’t really need to be reversing a lot… KennyV.

 

[dannyk]

Kenny,

But when you do this, do you drop the engine rpms when shifting to reverse? If I understand you correctly, you always drop the rpms to idle using the foot throttle when shuttle shifting, even though this will also drop the pto speed?

Sorry, still a bit confused. By the way, I did find the thread entitled "Why use clutch with GST" that was started on 9/27/06. There's lot of useful information there that I have to study.

Danny