Scott,
Over the years, past owners have substituted parts on their trikes that were not authorized or approved by the original manufacturer. In many cases out of necessity, but in most cases they were being thrifty.
If you have a 'stock and unmolested' Lehman Trike conversion on your GL1800 Goldwing that was built before August 2004, you have a Monarch I with drum brakes.
If you have a 'stock and unmolested' Lehman Trike conversion on your GL1800 Goldwing that was built AFTER August 2004, you more than likely have a Monarch II with DISC brakes.
The Monarch I had 2 different style driveshafts and the later model Monarch I had a specific Lehman driveshaft that is not produced anymore. The earlier style driveshaft can and is being used as a replacement for the later with slight modification to the swingarm tube.
Why did Lehman do this ???????
I don't know !!!!!
The front yoke of the Monarch I is essentially a Valkyrie front yoke.
https://mjtrikes.com/shop/index.php?...bc99dab412795f
The front yoke is a slip design and uses no fasteners or clamps to hold it on the output shaft of the transmission and sometimes the front yoke will become stuck on the output shaft of the transmission, accessing it from the engine RT side panel behind the mastercylinder, with a long punch you should be able to dislodge it. Reaching into the driveshaft tube of the swingarm, you should be able to remove it.
Once removed, the driveshaft must be pre-assembled (properly phased) before installation, period.
The front yoke of a Monarch II (until 2012) is the OEM GL1800 driveshaft. If you are unable to remove the front shaft from a Monarch II, the same method should apply.