OK....you made me curious so I just went out and tried that test on our
M59. Ours is one first M59s made, a thousand hours on the clock, and it is stock i.e. No additional wheel weights or tire fill. I didn't know what to expect - honestly I had my doubts the backhoe would lift the tractor at that geometric disadvantage - but I had to give it a try. Kinda hate to tell you this, but ours did the tests easily. No hesitation at all. Sure surprised me. Are your tires loaded? Would that make a difference? I set it up at our typical warm-up idle of 1000 rpm and left the front loader bucket vertical and jammed into the ground. Did not lower the backhoe legs at all. With the boom and dipperstick fully extended and the bucket teeth pointing vertically I first tried the boom cylinder. Not surpisingly the boom cylinder easily lifts the rear and front wheels of the tractor while pivoting on the edge of loader bucket.
Then I tried your test doing the same move but using only the dipperstick cylinder. That way the geometry is more difficult because it requires that the backhoe not only lift the whole tractor off the ground, but since the dipperstick rotates as it lifts it also has to drag the loader bucket backwards through the ground. I wouldn't normally do that; using the dipper cylinder alone without the boom cylinder to aid it isn't the kind of move I'd make when digging. It seemed to me that doing that puts a lot of stress on the system, but to my surprise the backhoe didn't seem to care. At that same rpm it lifted the tractor even though it had to drag the loader bucket backwards through the dirt at the same time. My dirt driveway now has a couple of new divots ...
Next I extended the bucket all the way so it was flat on the ground pointing out away from the tractor and tried the same tests again. That's an even more difficult geometry with even less leverage, but there was no difference except to prove that the BH will also lift and drag the tractor simply by rotating the bucket when fully extended.
None of the tests loaded the tractor motor or caused any hesitation at all. It did it all easily without even noticing. The over-all impression was that the backhoe didn't know or care whether it was lifting the tractor or not. It has way more than enough power to do any of those tests. That's not always good because the
M59 backhoe can sure throw the tractor around when working. Several people have remarked on that.
All the tests were at fast idle with the throttle set at about 1000 rpm. I usually warm it up at that rpm, and rev up to maybe 1250 rpm when doing backhoe work in rocky ground. Digging in regular dirt is much easier on the machine and so for that I'll rev up to about 1400.
You might want to check the system hydraulic pressure on yours. I've heard that some M59s came from the factory with the hydraulic pressure set differently and apparently it is an simple adjustment. I'm betting it is something simple.
On the HST+, in ten years now I haven't heard of anyone having problems with the tranny. I agree; HST+ is very convenient.
Let me know what you find out,
rScotty
