Operating the winch on an M51 Dump Truck

[Robo McDuff]

I have been looking through TMs and threads quite a lot now, but I am missing something.

According the operating instructions, with everything in neutral put, unlock the winch control lever and put the winch control lever in position Low or High, or even more speed levels in between.

No problem.

The M51Dump Truck has a dual PTO. So if I understand correctly, both the front winch AND the dump hydraulic pump are served by the same PTO and engaged by the same PTO control lever. Lever completely down - PTO drives hydraulic pump, lever completely up drives winch. CORRECT??

What happened with the H and L positions of the winch? Compared with the standard w/w trucks, the completely down position in the M51 is taken by the dump control. In the TMs, I saw the winch procedures always referring to the standard truck, and the dump control referring to the M51. But the positions now overlap, and I did not see that addressed in any operating manual.

Other question. I saw some threads on it, but did anybody ever completed an air-driven shifter for the PTO on an M51A2?

 

[simp5782]

M51 dump or winch-control keeps PTO running?

I've not used my 5-ton (M-51 dump) for years now while working on it sporadically. Getting it running recently, I noticed that for some reason now, the two transmission PTO shafts spin always - the only thing that halts them is the clutch being pressed. (On this variant, one shaft runs front...

www.steelsoldiers.com

 

[BEASTMASTER]

hey pal , I've got a 61 m-51. the one pto does work the winch and dump ," BUT " they are engaged separately.. OK the dump lever all the way forward engages the pto for the dump ONLY. the winch lever only engages the WINCH, which has IN, hi and lo, out, hi and lo. I hope that helps you.

 

[gringeltaube]

... the WINCH, which has IN, hi and lo, out, hi and lo.

Almost... OUT is only one speed and it's about in the middle between IN-high and IN-low.

 

[Robo McDuff]

Almost... OUT is only one speed and it's about in the middle between IN-high and IN-low.

Which still leaves the question which positions the PTO control lever has in the dump. By feeling in my 1965 M51A2 (overhauled completely in 1973), it feels like only three:

Forward down: rear output shaft turning
Neutral: standing about 60 degrees up, the lever can be locked in this position by the little flap on the tunnel.
Backwards in upright position, almost hitting the passenger seats. This should turn the winch.

Now if I understand your comments, the arc between neutral and hitting the seat are actually three positions: in low in high out low?

Gringeltaube, I had seen your comments in the thread referred to by simp5782 (thanks) also already, and frozen links definitely was part of the problem, levers seem to work, but in reality the final link did not. Also, the winch was completely blocked. Luckily, never tried to move that one with running engine. I WD40ed and greased whatever was possible, sometimes removing the grease nipple and cleaning it out first. The Dump Control Lever is now working completely smooth and free now. I put back the final link to the control box and it goes thru the positions smoothly as well. The winch has been completely disconnected (overhaul is next job) and the propeller shaft between PTO and winch has been removed. Last thing to do now is to take of the universal joint from the front output of the PTO and we can start test it with running engine.

hey pal , I've got a 61 m-51. the one PTO does work the winch and dump ," BUT " they are engaged separately.. OK the dump lever all the way forward engages the PTO for the dump ONLY. the winch lever only engages the WINCH, which has IN, hi and lo, out, hi and lo. I hope that helps you.

That exactly shows the problems I have after reading the TMs. How you write it (and the TMs), it appears as there are TWO levers in the middle of the cabin on the drive tunnel: dump PTO and winch PTO (three if you count transfer case).

But probably, I have a reading blind spot. I am (was) confident the cabin PTO lever itself was involved in dump operations.

However, I noticed that the moving the Dump Control Lever (beside the driver seat behind the hand brake lever) on the control box also moves the link to the rear shifter shaft between PTO case and control box as well. The rear shifter shaft is in other places in the TMs also called the power take off control rod. So much for uniformity of naming.

I will recheck how things work on my truck. The one position (with stopped engine) I had not tried is the cabin PTO in neutral and the rear shifter shaft in engaged or free position. I now have disconnected all output shafts on the PTO, and with force on the shifters I managed to get both shafts in Neutral. I will see what happens if I start the engine with the PTO control lever in the cabin in neutral locked and I move the Dump Control Lever.


If so, problem solved. I will also see how much the Dump Control Lever moves the rear shifter shaft linkage on the control box and how much the rear shifter shaft has to move between free and engage. Depending on that, I will not longer try to force thing in place but adjust the linkage length if possible.

Inside - outside the truck. The few times I tried 10 years ago, I operated the dump while standing outside the truck. Is that a big mistake or can you do it with the M51A2?

Edit: rewrote this about an hour after posting, realized maybe I was barking up the wrong tree and "misunderstood" the TMs.

 

[Robo McDuff]

OK, my bad.

I had all shafts disconnected from the PTO and the engine running. And yes, off course it works how it should. Don't know where I got the idea from that the winch lever also operated the dump. Probably because the PTO is dual, and the winch shifter and the rear shifter shaft are close to each other. Mind you, that should have made me blink but ... too many other things on my head and a bad cold and and ..... just plain oops.

There still is another problem with that system tough, but at the dump section, please have a look on that thread as well.