prefer HST tranny, more so in a jack of all trades tractor, that will be doing a little of everything. i get into to many situations were i am constantly changing gears, and going from forward to reverse. a manual foot clutch i have to press down every single time i have to change gears or go forward to reverse, is frankly a foot/leg/lower back killer. and it takes extra time to shift.
HST, is normally a simple button on the gear shifter to press and shift gears. and more likely a left hand lever near stearing wheel to switch between forward to reverse.
the problems i do not like with HST. is being able to place tractor in to high of gear for what you are wanting to do, and over drive the HST. causing extra heat build up of the transmission.
manual shift transmission, you can stick it down to 1st or 2nd gear and know you will have that power. and you can keep an eye on the RPM's so you do not red line the tractor, and keep eye on engine temp gauge so you do not over heat the engine.
but again, above i noted, a jack of all trades tractor. if you uses would be pulling farm equipment plow, disc, etc... i might choose manual shift. but i would most likely still go for HST tranny. it keeps the wear on the body down. and end of day, you can actual stand up and walk to bed, vs hunched over, with ice packs tied to your body, and then once in bed turning on the heating blanket. due to consonantly pushing in the foot clutch all day long.
a few extra HP lost due to HST. to me is worth it. if i am down to the money and counting those last 2 cents for power lost due to HST. then i am already in more trouble. and should be using a bigger tractor in first place.
HST also frees up either a hand or foot. so i can operate one foot for gas pedal, other foot for split right and left rear steering brakes. one hand to steer, other hand to shift. when ya get stuck, having ability to control things can help getting unstuck easier. or simply doing something. vs having to constantly press in the foot clutch. to change gears.
P.S. make sure you locate all the oil coolers and radiator. and keep them clean of debris. some tractors can be down right pain, in what you have to go through. to get an air nozzle down to oil cooler or radiator. to blow the stuff out of the grills on them.
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for a jack of all trades tractor, doing a little bit of everything. having position control, float control, weight transfer setup for 3pt hitch can make life easier. vs constantly having a hand on the lever to lower and raise the 3pt hitch. just setting in the seat and pulling lever is one thing. but you need to position yourself. so after a few hours of looking forward and looking back ever few seconds to keep an eye on things. is that lever in a good position. or is your neck, back, shoulder arm muscles going to end up killing at end of day? PTO on/off lever is it in a good position. while you may not be constantly turning PTO on/off but think about seating in the seat and being fully dresssed up for winter. with a few cover of cloths. do you have to reach between your legs and kiss your rear to deal with lever. or will you be constantly hitting it, with thick jacket/coat on?
FEL levers or joystick, is it in easy reach, or are you having to lean forward to use it?
if going with a 3pt hitch backhoe with subframe any time, does seat allow you to do a 180 and operate the backhoe? (makes for quick easy work with backhoe) or do you have to get off tractor and hope on backhoe seat to operate backhoe?
do you have room for a tool box to keep, a plier, channel locks, shear pins, some wire, hammer. so if you do break down you have a way to fix things up to get ya back to the shop, or be able to replace that shear pin or like without having to go back to shop.
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again each tractor model from the different manufacturers will be different. and some setups can be extremely funky. and given tractor more likely built and setup for this and that. were tractor will only be used for some specific tasks. and if there is need to get unstuck or doing something repeatedly over and over throughout the day. it will only be short term for project and the operatorter just has to deal with it for that one project. while all other tasks it works better for the operator.