826 Hydrostat

Now, on my mower, if you're going full-speed forward or back, and you suddenly jerk the lever back to the middle, it stops-right now. Make the tires slide even!
As for this tractor... You coast to a stop. Eventually. First thing done was to fix the brakes.
Second: the "clutch" pedal. Try this: push that pedal down while moving, slide the lever to neutral, and release the pedal. I've a habit of holding the clutch pedal (which is only a hydraulic release valve, according to my book) until the tractor stops. Having put the lever in the neutral position, I'd expect that when I release the pedal, the tractor would stay put. Not so; it'll start moving again and then coast to a stop. Boy, I'm glad I fixed them brakes!
(I've learned to lock up the brakes before releasing the clutch pedal. This makes a new loud 'whooshing' noise lasting about 3 seconds, but then when I release the brakes the tractor doesn't move.)
Third, I can live with a little hydrostat hiss. I'm used to that. But what's with the loud buzz-saw-on-sheet-steel noise that happens at about 1/3 and 2/3 throttle?

(Looks like oil seepage on the side of the hydro, in front of and just under the cab. I'm guessing the previous owner did some playing with it.)

Tach and hour meter didn't work when I got it. Speedometer quit a couple days ago. But today, as I did a U-turn out of one field and into the next, I witnessed the tach spin up to about 1500rpm before suddenly quitting again. I'm thinking this shouldn't be that big an issue to fix...soon as I'm done planting with it.

Hydraulics bleed down. I've seen that happen before, it's usually a question of finding a bad O-ring someplace. But this is a new one on me: this one bleeds down--with the engine running, even at full throttle! All the hydraulics seem to work, it just bleeds down.

Finally, this tractor has a Year-A-Round QT-1 cab. It's like a tin box with (stuck) windows. What can I do to dampen the noise? Wearing hearing protection (ear muff style), if I sit down I hear a deafening roar in the sub-200Hz range. If I stand up I hear the hydrostatic whine, also at more-than-unpleasantly high volume. But that low roar drowns out the whine when I sit.

So, to summarize my problems: the hydrostat is probably needing adjustments, the hydraulics need work, some gauges are not working. And boy oh boy, is it loud!

Where do I start?

Thanks!

It shouldn't "coast to a stop". That function is controlled by the anti-coast valve and is located in up the control manifold. A lot of guys call these two valves "capsules". Takes about 3 minutes to swap 'em out.

Don't worry about the "clutch". All it is, is a "dump to sump" needle and seat, which empties the line pressure. Just don't see how you can hurt it by using the clutch.

Hope ya get 'er figured out,

Allan