L3750 hydraulicshuttle shifting issue

[heppeone]

My Kubota is having an issue shifting. Has the hydraulic shifter where there is not a need to use clutch to shift F-N-R, but now there is a hesitation/delay in what seems like hydraulic pressure build up engaging forward/reverse gears. Worse going forward. Fel will still work fine while waiting.

Thoughts? Clutch, hydro valve, other? Have new oil/filter already, prob was there previously

 

[bigbull338]

sound like there is a few things you can try.change the hydro oil and filter and see if that clears things up.your filter could be stopped up for some reason.

 

[rbargeron]

The hydraulic shuttle on these early L3 models have an adjustable orifice valve to control how quickly the shift takes place. It has three positions - for hot, moderate or cold climates. Maybe some skudge is affecting your valve.

The orifice valve is located on the end of the main shuttle valve - inside the cowl, forward of the instrument panel. It has a small rotating lever with a pin that can be pushed or pulled with a hooked tool. By unbolting the column covers and lifting the panel the orifice valve can be adjusted without removing the steering wheel. To adjust my L4150 I used a fishing rod tip - and a bright light to help see in there. Hope this helps.

 

[heppeone]

Thanks guys. Changed oil/filter before the post, was my first thought but no change on performance.

Will check for adjustment screw next.

 

[heppeone]

The hydraulic shuttle on these early L3 models have an adjustable orifice valve to control how quickly the shift takes place. It has three positions - for hot, moderate or cold climates. Maybe some skudge is affecting your valve.

The orifice valve is located on the end of the main shuttle valve - inside the cowl, forward of the instrument panel. It has a small rotating lever with a pin that can be pushed or pulled with a hooked tool. By unbolting the column covers and lifting the panel the orifice valve can be adjusted without removing the steering wheel. To adjust my L4150 I used a fishing rod tip - and a bright light to help see in there. Hope this helps.

I see the lever arm in picture of Shuttle Control Valve from WorkShop Manuel I have, any advise as far as to which way to move for season? Manual does not speak of this lever, but does speak of shims used inside to increase/decreased pressure after pressure test.

 

[rbargeron]

I no longer have my L4150 WSM which showed the valve and lever - and I don't remember which way I pushed it. There are only three positions it can click into - try them all to see what difference it makes.

The adjustment allows dealers to set up the tractor for the local climate. When set for the most rapid shifting (largest orifice) the tractor will change directions abruptly on hot days - maybe too quick. Some of the newer shuttle valve designs are less dependent on oil viscosity and don't have the adjustment.

In your L3750's case it may already be set to the smallest orifice and is being further restricted by something. Setting it to one of the bigger orifices might flush it out. It's something you could try to see if it helps.

BTW, "normal" performance of the loader is a good sign the hydraulics are healthy and the problem is confined to the shuttle control. Also, it's doubtful the pressure shims are involved in this - they don't suddenly change performance.

 

[heppeone]

Thanks Rbsrderon. Sounds like spot on advise

 

[heppeone]

Took instrument panel off and saw valve first hand. Tried what you just said, move and check difference. Your right about the quick hard shift, will keep fingers crossed that it may flush something out.

 

[rbargeron]

If the orifice itself is gummed up it may not flush out - but the other 2 should still be new and clean. Another thing to try would be switching to SUDT transmission oil. Viscosity of synthetic oil is less affected by temperature.