Have a go at adjusting it:
SHIFT LINKAGE ADJUSTMENT
1. Loosen the three shift linkage adjustment nuts. Install a 1/4 inch diameter alignment tool through the control bracket and levers as shown in Fig. 3, 236K.
An alignment tool can be made from 1/4" diameter drill rod bent to an "L" shape. The extensions should be 1 1/2" and 3 3/4" from the elbow. Short end of alignment pin should be inserted into control bracket and linkage holes until it bottoms.
2. Tighten the three linkage adjustment nuts and then remove the alignment pin.
3. Check the gear shift lever for a smooth crossover.