e_student, we got a MB trac 1500 1985 model. The transmission on this tractor is the same as on the Unimogs. Difference: Unimog has 8 gears to shift while the Mb-trac has the 8th gear blocked. By taking off the shifter cover from the transmission and using a grinder, one can easily remove the blocker and go much faster than 40.  I'm fairly sure that ours will go over 60 Kmh.   We do Spray with ours and it goes good.

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MBsprayer.jpg (66KB - 225 downloads)