I just purchased a 2005 Honda VTX1800 with a Motor Trike conversion. The seller knew nothing about the conversion so I want to do whatever maintenance I can ASAP. Oil change and air filter done. I'd like to change the differential fluid but can't locate a filler plug. Also, I'd like to grease the universal joints on the drive shaft...but no fittings. I'm about 200 miles from the nearest Motor Trike dealer. Can anyone talk me through this?