Videos like this are what make YouTube worthwhile.

I was repairing a new skid steer, where one side had no power.  Took it apart twice, without finding anything.  The factory sen.t out an expert, who found nothing.  The company sent out a new unit, and the old unit sent back.  A few weeks later they diagnosed the issue.   The pump and motor use the same size pistons, but the slippers are different.  Someone put pump pistons in a motor assembly.  There was .0001 difference in diameter in the lube holes in the slippers on the pistons.

Imagine the brain power it takes to dream up an invention like that.

My friend rebuilt the powertrain for a 15” gauge miniature train locomotive.  The train as built in 1947 used a simple clutch between the gas engine and the driveshafts for the trucks.  Obviously, it had no reverse!  When the clutch suffered a catastrophic failure, we could not find a direct replacement for it or even parts to repair it.  The most recent parts list from the manufacturer was dated 1963.  So we swapped the ancient, smoky Onan motor for a new Honda 25HP and, instead of the clutch, used an Eaton Series 11 hydrostat.  All it took was moving to motor mounts forward a few inches and fabricating a couple of brackets for the transmission.  We got excellent power throughout the speed range, plus a reverse.  No more pushing the train backwards 400’ to put it away at night!  It helped that the company I worked for was an Eaton distributor, so I got him the employee price of cost + 10%.

As a 'mechanical layman', this explained how hydrostatic transmission works simply & clearly - well done, and thank you!

I have never learned so much in 15 minutes about concept and operation of a hydrostatic transmission. I have been wondering about this for decades. Your presentation style is the best I’ve seen on youtube.  Thank you for taking the time to share your talents. They are a gift for all, and best 15 minutes of time spent learning in quite a while!

terrific explanation of a hydrostatic transmission

Swash plate pump, swash plate motor. Lucas improved the efficiency of fuel pumps on gas turbines engines with their swash plate pumps, instead of the gear pumps that were being used. They pump the amount of fuel required as opposed to the gear pumps which pump the maximum amount of fuel which is bled off when not required.

I just love the amount of entusiasm when explians the math of the transmission. And at the end, as a final conclussion, he finishes it with a "pretty cool". Love it.

What an interesting way to create a continuously variable transmission.
Thanks for taking the time to rip one apart and dig into the subject!

This is the same idea as a variable piston pump only one pump drives the other. Wild

I've even driven tractors with hydrostatic transmissions.  It's a weird feeling when you're used to old school manual transmissions on them

When I was growing up in the mid 70's we had a Wards 16 horse garden tractor that had hydrostatic drive and I knew it was a hydraulic pump and motor but watching this video it was more simple than I thought

Appreciate the explanation. How these mechanisms are conceptualized and manufactured is amazing. I have a compact tractor with a hydrostat, which is super convenient and smooth compared to the traditional gear transmission. I could picture early farmers being skeptical of this incredibly complex mechanism initially though.
The whole rotation mechanism is similar in concept to a helicopter rotor  hub with the awash plate, connecting rods and bearings.
I’m going to go easier on my ride on mower and tractor now, keep ‘em in low gear. Stuff is intricate.

It's a simple concept, brilliantly executed.

Man!!!!that was an awesome explanation, I'm 53yr old, been running and repairing heavy (and smaller) equipment 34+yrs ....often wondered but never knew, I appreciate you taking the time to break down and explain,  I'm saving your channel.  You'll definitely be another one of my go toos:)

Very cool instructional video!

I felt like Alton Brown was teaching me about transmissions!

You have a great speaking voice and cadence to keep the audience interested.

This is a video I've always wanted to see.  Thanks for making it!  Now I have to go check out your others.

Thank you, for enlightning me on the hydrostatic system, you do good!

Smartest man on the interwebs usually these type of video there’s like an insane amount of cutting done to make it look consistent but this guy just makes sense normally and he’s not even going off a script , insane my guy