I have a K4 Spectrum series that "wags" from side to side . I can not figure out how to remove the shell so I can lubricate and check for bent axles.  Also would the valve gear binding be more likely to cause this . ( It looks good and I can not see any issues) I can attach pictures to another email   (the pictures are to large to attach )
Thank you
dmiller

Does anyone know the difference between an Item# 81903 HO Scale 3 truck 80 ton Shay (Greenbriar and Elk River) and Item# 91907.   I am looking at a NWS replacement 3 truck gear set for: Item# 91907 Which is also  a HO scale 3 truck 80 ton Shay  . What is the difference between the two Item # s?

I am Needing to replace the gear to the front truck  front tire  and NWS lists it as: Bevel Gear, HO Bachman 3-truck Shay (81907) 80-ton, 3 Truck upgrade bevel gear (6)  Part Number:  2800-6   ( No picture available )

https://nwsl.com/products/bevel-gear-ho-bachman-2-truck-shay-81907-80-ton-3-truck-upgrade-bevel-gear-6


Thank you all!!