Originally Posted by TRUKTOR
SURE JEREMY, if you'd like to post that E-mail it wouldn't hurt any. I'm buried in LA on a very looney Gwen Stefani commercial, so I won't see the light of day for a week or so...Thanks.
Ok John. Hopefully you're having fun on location though;
"As for the CLAAS unit, it is a 22% overdrive in every gear, so ROAD &
WORKING GEARS = 16/16 X 2 (splitter) =32/32. Now, I don't know anybody
that goes through a series of shifts in reverse, but you can do it...I
did it just to have done it.
The CLAAS unit is triggered with a little tab that is welded to the
[BOTTOM OF THE] clutch pedal, which hits a solenoid that shifts the unit from LOW (NORMAL)
speed to HIGH(22% OVERDRIVE), depending on the position of the TOGGLE
SWITCH, which is mounted on the main gear shift lever.
So, in use, it goes like this : I'm heading towards a hill on the way
to the house in the woods,I'm in 8th HIGH (TOGGLE IS UP),
I know I can't carry the hill in 8th HIGH, so I click the toggle DOWN;
nothing happens(nor is it supposed to ).Then, just as the truck begins
to bog or lose revs on the uphill, I stab the clutch ,without touching
anything else, and I've downshifted 22% TO
8th LOW (which is the NORMAL UNIMOG 8th gear), and I continue up the
hill. If I think it is going to require another downshift, I move the
toggle (and nothing else) back to the UP position, and when the time is
right, depress the clutch pedal,DOWNSHIFT THE LEVER FROM 8TH TO 7TH, and
I am in 7th HIGH (22% OD), and we are carrying the hill again. I can
move the toggle minutes before I'll need the gear and hit the clutch
whenever, OR, I can hit the toggle as I shift and do it all at once...It is
easier to "pre-select" a gear and just stab the clutch, as then you
are not moving the gear shift lever, but that only works within a
Now , in a practical sense, I don't use the CLAAS unit around town
much. You want to start the UNIMOG in 5th from a dead start
(according to SEAN and a number of other guys), and go on up from
there. The trick is to not "use" the clutch upon starting out, just dump it
and go, no slipping the clutch to get the beast moving, just dump it
and let the UNIMOG pull itself up by the torque and get rolling. Sounds
brutal, but that is the ordained way, in order to preserve the clutch.
This procedure is easier if one starts out in 4th, not 5th, but nobody
tells you to do that. WHY? You might well ask...Well, the synchro in the
4th to 5th
upshift is rotten, and has a tendency to grind. My transmission is
newly re-built, and it will do it. Brand new U1650's and
U1450's (5 different ones) all did it, and they were brand new! You
have to wait on that shift, hesitate, wait, wait, and then go to 5th. Mine
is fine once it is warmed up to operating temps, but when cold, I skip
5th and go from 4th to 6th. Once it is warmed up, 5th comes back into
the mix. They all do it. Sean told me every one he has driven did it,
and that goes for me as well.It is no big deal, you just have to know
So, around town, start in 4th or 5th (NORMAL), and go up and down,
staying in the normal ranges (TOGGLE is DOWN), and it is all fine. You can
play with the O/D if you want, but there isn't much reason to split
stuff, unless you are wanting more top end, or
you are dealing with hills as above.If you decide to use it around
town, you are increasing your clutching for no real advantage.
Maybe people on the street will hear all of these short shifts and
wonder how many gears that dang thing has, but, for me, I don't bother.
There are two ways to look at it: A. THE CLAAS will give you
(potentially) 22% more top end , but your trans, axles, driveshafts are also
going 22% faster than "NORMAL", or B. at a given speed (say 60MPH), the
CLAAS unit will slow everything down 22%, which means it is all turning
22% SLOWER than NORMAL,and is that much quieter FOR THAT SPEED. So, if
you use it a bit for this (22% faster) and a bit for that (22% slower),
you wind up with NORMAL, as far as wear and tear. In Germany, the CLAAS
unit has a good rep for durability.
The top end is POTENTIALLY 22% faster, but unless you have the
horsepower to turn the big tires (XM-47's), you will run out of grunt before
you run out of gear.
Off road, or when winching is when the CLAAS unit really shines, as it
gives you twice the ratio choices, more or less. You just have more
flexibility for the terrain/speed equation. When winching, you can more
easily match the truck speed with the drum speed of the winch, simply
because you have more ratios to play with."