Owner-Produced Paperwork Required

This mostly-new / functionally new Dukes-type Piper Comanche landing transmission basic assembly P/N 25720-003, without motor, release, coupler, or brake assembly, as shown below is $3,600 exchange plus shipping and insurance. The black and red components are powder coated and the other pieces cadmium plated, includes new placards. The updated bushing [safety issue] P/N 21038-007 is included, also owner produced.

P/N 25720-003 below includes P/N 21855-000 release components, but without P/N 21286-000 motor, 24948-000 brake assembly, or new coupler P/N 757-833.

This “new Dukes type transmission” can also be interpreted as a “repair” to your crappy Dura transmission.


P/N 25720-000 – transmission complete with release, brake, new coupler and OHC motor. After installation of your new transmission, ship your old assembly but you have only 2 weeks for this option; I need the motor and other components for exchange and refurbish for future transmissions. I charge a hefty core unless I know you; then it is optional. I trust most but a customer in Johannesburg, SA stiffed me; I trusted him too, but no more.

Similar service requirements apply as the original Dukes transmissions, i.e. 500 hour or annually; disassemble, inspect, and lubricate with Dukes specification #4 lubricant. The ballscrew lubricant specified in the SMs is AeroShell® #7 at annual and 100-hour intervals; I suggest using Aeroshell® #64. AeroShell® #7 just doesn’t lend itself to longevity of ballscrew life. Aeroshell® #64 contains 5% Molybdenum Disulfide, an extreme-pressure additive. The original ballscrews would have lived longer with regular use of this grease; ballscrews are a common failure, all of my transmissions are supplied with a new ballscrew assembly.


P/N 25720-003 includes P/N 21855-000 release arm components, without P/N 21286-000 motor, brake assembly, or coupler; $3,600 exchange each.

To simplify all this information, if you want an almost-new everything P/N 25720-000 the price is $4,500 exchange. See the “new” motor. This option includes a new coupler and new plunger-style brake assembly which are also owner- produced components.

Compare this to an exchange Dukes transmission if you can find one, that may not have any new components; $3,995. I sold an NOS Dukes for $5,000 in 2020, another shortly after for $5,500.

Dukes quoted/guesstimated between $7,000 and $8,000 more than 12 years ago for the sub-assembly P/N 25720-002 pictured above, without release arm components, motor, or brake assembly.
Photo for reference only, not for sale in this configuration.


Complete landing gear transmission assembly P/N 25720-000; using your serviced motor.


Complete landing gear transmission assembly P/N 25720-000 with “overhauled” motor.

The “overhauled” motor is available separately for $650 exchange. These motors have new field coils, rewound and dynamically balanced armature, new Kevlar pole shoe insulators, new springs and brushes as necessary, repaired brush holders as necessary, MIL-Spec wires, properly re-impregnated Oilite® bearings, and cadmium plated housing. This is as close to new as you can get.


Considering these old motors have performed 50 plus years in service, in my opinion why ask another lifetime from them. This non-FAA “overhauled” [owner produced] unit is the problem-solver. Non-FAA because nowhere in either the Piper Comanche single or twin service manuals is mention of these nor the flap motors. Official FAA overhaul language would apply if there was stated criteria, and the agency was FAA approved. I was previously supplying motors from an FAA approved repair station; after multiple failures I pursued my own approach.

The failure mode of the flap and landing gear motors is the insulation of the copper magnet wire windings in both the fields and armatures. Few entering my shop pass this test, however some do especially if newer production date.


An insulation tester is required to analyze the copper magnet wire insulation condition.


Flap Transmission P/N 23013-000 — Complete Flap Transmission Assembly P/N 23013-000 with “overhauled” motor


Same treatment as the landing gear motors the flap motors have new field coils, rewound and dynamically balanced armature, new Kevlar pole shoe insulators, MIL-Spec wires, properly re-impregnated Oilite® bearings, and cadmium plated housing. This is as close to new as you can get. $550 exchange.

Contact Comanche Gear

Please provide your complete details for invoicing such as your Card Billing Address, Shipping Address, and Aircraft Information. If you want to gab on the phone don’t hesitate to call, especially if you want to order something. If you have a problem-solving dilemma I can help with that too. This website doesn’t have internet ordering capabilities; that is for those more sophisticated. My email isn’t shown here because of scam artists and other shenanigans.

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