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406 forst
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Discussion Starter #1
I am new to Unimog's. I just had a Unimog 406 with 6 speed transmission (UG 2/27) delivered from across the country and didn't inspect it. The transmission shifts smoothly between 1st and second but I can't shift into third gear or higher. The main shift lever won't move laterally even when the engine is stopped but I think someone on this forum mentioned there could be a problem with oil pressure. I have both the owner's manual and the service manual but there is no troubleshooting guide for shifting the tranmission.

I don't know if I am shifting it properly. There seems to be some sort of 'gate' that you have to pass to get into higher gears.
 

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Hi Kool! I had the same trouble and I bet many people do. 1 and 2 are considered low off road gears and are locked out from the main drive gears 3-6 in order prevent accidental engagement at higher speeds. Hopefully all you need to do is find neutral,let the clutch out and then shift past the gate.

I mentioned in another thread that my shifter was stressed cracked and I got to be the one that snapped it off. It occurred to me that others may have cracks too, or maybe it was an inclusion in the rod. When I first tried to shift it I was trying to apply only enough force to overcome what might be a sticky shift, but any number of unfamiliar people that had to move a truck that didn't belong to them would be more likely to get frustrated and abuse the shifter.
 

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'78 Mog 416.141 DoKa
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3,420 Posts
As Daniel said, there is a gate between 1-2 and the higher gears. Until you're used to the motion of shifting through this gate, it can feel like something is broken.

You don't need 1-2 on the road, unless you're reversing. Starting up in any gear below 3rd is a useless exercise. Consider your trans to be a 4-speed on road.

The more you use the gate, the smoother it will get.
 

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406 forst
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313 Posts
Discussion Starter #4
My Forestry Mog has a rear sprag which, when lowered, lifts the rear wheels off the ground. I was able to experiment with various combinations and get the feel of the shift gate.

I am greatly relieved that I do NOT have a transmission problem. Thanks for the tips! [:D]
 

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2001 S500
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To get through the 1 2 gate I use a double bump with the heal of my palm rather than shoving it through. With a little practice it works quite well. I can shift from 2 to 3 without rolling to a stop. Now lets see some pictures of this forestry beast!
 

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406 forst
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313 Posts
Discussion Starter #6
Thanks for the tip H20Diesel.

I am still waiting for a camera. Meanwhile here are pics from the ebay transaction (they will be deleted soon).

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4530171942&rd=1&sspagename=STRK%3AMEWN%3AIT&rd=1
 

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unimog 406,121,13004657 first reg date 20,05,1966 5,7 diesel.
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5th gear problem

hi
my 1967 406 6 gearbox does not enter the 5th gear. the mog has about 6000hrs. all other gear works finer. the shifter has a good deal of slack. any idas? i have not opened the tanny yet. when i try to put it into 5th , it scratches and does not enter.

tks
 

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link no longer good. lets see some pics. the forestry mogs are second only to race mogs. Ag following a very close 3rd.
 

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1976 406 w/ backhoe and dozer blade, a small collection of implements too
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1,498 Posts
I second that. I'm trying to make mine into a nice forestry/ag mog. Split personality is an excellent trait amongst these machines.
 

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unimog 406,121,13004657 first reg date 20,05,1966 5,7 diesel.
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406 5th

hi
my 1967 406 6 gearbox does not enter the 5th gear. the mog has about 6000hrs. all other gear works finer. the shifter has a good deal of slack. any idas? i have not opened the tanny yet. when i try to put it into 5th , it scratches and does not enter.

tks
 

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U-406/416
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688 Posts
Nice rig Koolmoose, did you get your ROPS FOPS off an SEE unit, what size tires are you running 405 or 425. Everything looks great, keep up the good work.
 

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406 forst
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313 Posts
Discussion Starter #14
The ROPS is off a SEE. After scratching my head for months I moved the winches back 4 inches and adapted it to the winch mount.

The tires are 405.
 

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mogless, except for my friends MB4-94. And a bunch of other diesel junk.
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Koolmoose, your truck is looking bad assed right now. I remember when it was listed on ebay before you won it and it looked nowhere near as good. A real shame that they lost the hardtop and hood. Tell me a little more about the crane you've added to the bed, and the rear upper arm assembly (above the sprag) that has the cable pulleys on it. How's it working out for you?
 

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406 forst
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Discussion Starter #16
Koolmoose, your truck is looking bad assed right now. I remember when it was listed on ebay before you won it and it looked nowhere near as good. A real shame that they lost the hardtop and hood. Tell me a little more about the crane you've added to the bed, and the rear upper arm assembly (above the sprag) that has the cable pulleys on it. How's it working out for you?
Thanks esde.

Losing the hardtop may have been a blessing. I replaced it with the SEE hardtop which provides a more effective 'hardhat' in the woods. The crane is an old 'armstong' sign crane. It is pretty light weight; probably a good thing since I use the rear spade as the stabilizer. The crane has a reach of 40' but I typically only use 20' reach.

It is pretty steep where I live. I have been playing around with it as a light weight skyline. I self guy the crane to the front of the mog to support the load when used as a skyline tower.

The 'upper arm assembly' acts as an arch to provide some lead for yarding over obstacles when pulling longer distances. The cable pulleys swivel to provide fairlead. It works very well. However with a hard pull it can rare up like a horse. A safety line to a tree opposite the direction of pull will prevent this bad behavior.

Key word search 'unimog 406 forst' will show some videos that show how mogs without the arch operate. I haven't found any that show the arch in use.
 
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