[TRUKTOR]

OK, I am looking for some help on the nature of the Hydrostatic Drive on the SBU
Series. On the Snow Cutter I looked at yesterday, it was equipped with a drive as pictured in the photos of the Trans on the pallet. The instructions for using the drive are as shown. I suppose the Instructions on the red engraved plate echo the same instructions in German
which are under it.

I couldn't get the truck to do anything other than what you'd expect of a UNIMOG. Admittedly, I only moved it a few feet forward and a few feet back, but the Manual trans
worked as normal, the working gears also, but I could not get the thing to act as if there
was a HYDRO-anything, despite the position of the lever, etc.



I know some of you can explain it all to me. Thanks.

 

[TRUKTOR]

Gentlemen, thanks for the answers. The picture is becoming clearer,much clearer than mud.
We were planning on driving back out there again, so I'll probably have another go at it.

I....um...., noticed a button on the dash that is probably the missing link-at least a button
I failed to push, which was probably the difference. Maybe I was breathing the Automatic Ether or something. The Hydro Control Lever was DEAD, as in, it had no resistance like it controlled anything or was connected to anything, but I'd expect that would be different once the system was on and charged.

So, I get the concept, and you "drive" the truck via the Hydro Control Lever, which
on this truck is on the shift plate, but is often mounted up , off of the dash. So, depending on the speed you'll need, you choose a gear 1 through 4. (Can you be in the working gear range and use 1-4 ? I'd guess yes...) No Clutch, OK, understood. F/R in Neutral, OK.
And forward/reverse is determined by the Hydro Lever. What about speed ? Do
you use the "accelerator" pedal for speed, or is that also determined by the position of
the Hydro Control lever ? I'd guess pedal...but there is a range of movement on the lever
that might account for speed as well.

OK, so let's say I get it working and can move the truck with it. What are the advantages/
disadvantages to having a truck so equipped ? I understand that the Zweiweig Rail trucks
are often equipped with the system, and then you have this Snow Cutter. Is it all
about controlling slow speed work, or is it a way to put maximum power down gradually while taking it easy on the driveline ? Or something else ?

One disadvantage I see, if the truck were to be converted to "normal" recreational use,
would be the added complexity of carrying a system that you may never use. Or would
you ? Hypothetically, If you were to take this truck, after it shed all of the Snow Cutter equipment, to Moab, let's say, would you find a use for the Hydrostatic drive in that situation ?

Thanks for all the help, I appreciate it.Thanks for the generous offer of shipping the Manual for a look-see, w5yk, but I think it is a bit early for me to get too deep. It is an interesting
bit of UNIMOG equipment that I had never paid any attention to, so it is good to figure
it out, whether I'd ever really have to live with it or not.

A truck and a hobby all in one, it seems.

OOPS : The lower-left photo is Not supposed to be here-it does not show a Hydro static drive system.

 

[TRUKTOR]

YES, that bit of Jethro Engineering was apparently installed to PREVENT the use of the
lockers....Why, I could only guess.

A short wheel base, rear-steer UNIMOG with LARGE running gear, a Very Large Cummins
in back, and Tons of braces, drive shafts, Gearboxes and so on ....and a bonus :a muffler full of water...

And they don't want to be able to LOCK it up ?

There is a sticker that says not to use the rear steer over 15 MPH (Chickens...), but why they would eliminate the Diff Locks is baffling to me.

I'm not going to purchase this truck in any event, but a buddy of mine is all hot to trot, and I am doing my duty and leading him astray and down the path to UNIMOG ownership.

This might be a tough truck to start with, but he IS a tinkerer, and there is lots to
screw around with on this beast. I was trying to point him towards a U1300L, but he seems
to be vectored in on this thing.

There are a LOT of things on this truck that still need to be tested on the GO/NO GO
list before a price can be discussed with any reason...

This truck has no Mechanical PTO on it, nor does it have the AUX (belt driven) air Compressor or the standard Hydraulic pump (engine driven ), which is not to say it does not have gobs of stuff running all over it.

 

[TRUKTOR]

Thanks guys, I appreciate the help. I realize that IF I had taken more time while on site
and carefully read the RED plaque, I should have been able to pass the Jethro Test and get the Hydro Drive fired up. It was all there in Red and White. There
was a lot going on, my buddy was frequently asking "what is this thing ? Does your truck have one like this ?" etc...In Short, I flunked the Jethro Test. The shame of it all. I'll try for a do-over.

It is a very thickly packed chassis- all sorts of plumbing going on , as well as all the Snow Cutter equipment, sub frame and bracing and the rather low hanging auxiliary drive shaft. A lot to be crammed into the regular, short wheelbase. Physically, I'm not really ready to be squirming around on my back looking at trucks, a fact my body was happy to make me aware of both at the time and later.

Trev, thanks for the tip on the Genset Power plant. I'll pass it along.

 

[TRUKTOR]

Temperature info from the UHN book.

 

[TRUKTOR]

Here is page 201, which was referenced in the other post, and a couple more pages relating to the hydraulic system - this might not relate specifically to the Hydrostatic Drive - and the oil specs and everything else is from the UHN book, so specifications may have evolved.