Top speed on MB 1976 300D

[WGonzalez2]

I swaped tranys in my 300D, the old one with mechanical linkage modulation, the presently installed came from a 240D 1983. (The original I have it on the bench, in the process of rebuilding it. Came with the car not running-bad main pump, worn out crescent, and broken converter lugs)
Took it on road test and cannot get it to shift 4th. (does it have forth ?).
The trany car does not seem to be sleeping but just reving up like looking for one more shift.
I drove it with the vaccum pum on hand to supply different vaccum values to simulate de 240D.
How do I know when it has three or four speeds ? The shift stick has one 1-2-3 and R, so I assume that was a 3 speed.
The numbers on the trany are:
123 270 6302722 117 02 080663 (stamped on the edge near the valve cover)

R115 2709311 (foundry #'s on the rear casing)
37.4722.00 (foundry #'s on the rear casing)
R115 271 201 (foundy #'s on main casing -shift slector side)
Where to find the reference and meaning of all these numbers ?
Thanks, Wilson