Unimog Club UK

with the gears on this....... on my 404 I had a similar problem to start with, the low two, nearest you, 1&2, then in neutral push lever away one click, then another - quite a long way! but then you must push forward 3rd as mine had a sequencing device so that you had to go to 3 after 2! You cannot short shift - at least on the military 404! There are actually 8 possible gears in there but you have to mod the guts to get them! and reverse only operates in low - dont listen to anyone who says "ah you can take the interlock out and get high reverse" its bulls$$t! as the reverse gear is on the low range shaft... ask me how i know!!
If you want to take the top cover off to play...... park or jack the back of the vehicle so the gearbox is level, it normally slopes down towards the rear, that way when inside the box it prevents all the dogs sliding rearward every time you try and line the lid up! Bitter experience!
This is all assuming yours is similar to the 4041
Phil.