Trolling valves are available as an option on most models of marine transmissions. In most cases, trolling valves are easily retrofitted. A thermostatic oil by-pass valve may be required to maintain proper operation and recommended oil temperature. Consult ZF for details and limits.

Where non-standard ratios are indicated (+) these are available on request and may incur additional price/longer delivery compared to standard ratios. Consult ZF for details.

In principle, all transmissions are available as non-reversing units (for instance, for controllable pitch propeller applications). Many parallel shaft transmissions can also be supplied with input and output on the same side ('U'-drive). Consult ZF for details.

All PTO’S are retrofittable except where stated otherwise. Most transmissions can be offered with clutchable or permanently driven (live) PTO’S. Consult ZF for details and limits.