Help...shoudnt the tires spin ???

CobyRupert · Sep 1, 2015

There's always an ongoing debate over the pro/cons of hydro vs. gear tractors. If hydro's go into relief, then there's a black mark for them.

I understand why a hydro would have a relief valve, but good god, shouldn't it be rated/set higher than the maximums torques that the engine could produce? (essentially protecting the tranny if someone made post-factory modifications like boosting the fuel pump or adding a bigger turbo etc..) That is, the tranny should be able to handle any torque the engine can dish out and more.

If I buy a 40 hp tractor, I'd expect that all the torque would be able to get to the tires and the tires should either spin or the engine should stall. I WOULDN"T expect the tranny to go into relief at some lesser value! Otherwise I haven't bought a 40 hp tractor.
This is like having a gear tractor and expecting the clutch to slip if the wheels get too much traction and the load is too heavy.
TOTALLY UNACCEPTABLE!

buickanddeere · Sep 1, 2015

CobyRupert said:
There's always an ongoing debate over the pro/cons of hydro vs. gear tractors. If hydro's go into relief, then there's a black mark for them.

I understand why a hydro would have a relief valve, but good god, shouldn't it be rated/set higher than the maximums torques that the engine could produce? (essentially protecting the tranny if someone made post-factory modifications like boosting the fuel pump or adding a bigger turbo etc..) That is, the tranny should be able to handle any torque the engine can dish out and more.

If I buy a 40 hp tractor, I'd expect that all the torque would be able to get to the tires and the tires should either spin or the engine should stall. I WOULDN"T expect the tranny to go into relief at some lesser value! Otherwise I haven't bought a 40 hp tractor.
This is like having a gear tractor and expecting the clutch to slip if the wheels get too much traction and the load is too heavy.
TOTALLY UNACCEPTABLE!

In such a configuration when the drive train can take full power. Now when the hydraulic loaded is operated the engine will bog. Now some operators are going to complain about an under powered tractor . Can't win.

peter3759 · Sep 1, 2015

I guess my tractor is set to the minimum pressures for everything because I've never heard any of my relief valves blow off!

k0ua · Sep 1, 2015

Put a hydrostatic tractor in hi range on a three range hydro, and push up against an immovably object and the relief valve will relieve. On a gear tractor put it in your highest gear and push it against an immovable object. What do you think will happen? And if you say the the tires will spin on any kind of hard surface you a most likely telling a whopper. No the most likely thing to have happen is a bunch of clutch facing wear and a bogged down and dying engine.

I think a lot of folks don't realize that the range control is nothing more than a simple gear transmission behind the hydro. Why so many insist on using too high of a gear ratio for the work at hand is a mystery to me.

peter3759 · Sep 1, 2015

If I put my tractor in high I better be on a hard level ground, let alone trying to do any work! If I try to take anything more then a little scoop of the manure pile in med rang I can't do it! Low range is the only suitable "working" range for my 4041h! I have never hear my relief valve go off and I have stalled my tractor working in medium range a few times while in the process of learning that less pedal means more grunt!

Woodshaver · Sep 1, 2015

Ok won't talk about "ramming"
XR4046H No problem in M range moving with loads of brush and even pushing the piles up. Even been able to push some small trees up with roots. Have also stalled the engine doing this a few times but not much "tire spinning" in M range. No problem spinning tires in L range. Have not found much use the H range except for a small amount of road travel and our road is very flat.

CobyRupert · Sep 2, 2015

k0ua said:
Put a hydrostatic tractor in hi range on a three range hydro, and push up against an immovably object and the relief valve will relieve. On a gear tractor put it in your highest gear and push it against an immovable object. What do you think will happen? And if you say the the tires will spin on any kind of hard surface you a most likely telling a whopper. No the most likely thing to have happen is a bunch of clutch facing wear and a bogged down and dying engine.

I think a lot of folks don't realize that the range control is nothing more than a simple gear transmission behind the hydro. Why so many insist on using too high of a gear ratio for the work at hand is a mystery to me.

(IMHO): The "weak link" on a working tractor should be either motor horsepower (torque) or traction. Not a transmission relief valve (or slipping clutch) that doesn't allow all of the engine power to get to the wheels. Stall or spin!

RKJeepXJ · Sep 2, 2015

My R4047H will spin 3 tires on pavement in low gear. It'll go into relief in mid range. I can't complain with that. Theres a lot of variables to each situation as fat as ballasted weight and tire pressures and the surface you're on. I feel like mine puts down a good amount of its potential power to the ground before relief.

peter3759 · Sep 2, 2015

I feel like the 4047 is a more appropriate hp for that frame then the 4041 at least in the hydro. The thing I don't get I its all the same hydraulics so why does the 47 seem so much more responsive?