What is wrong with your motor?
I also have a Suburban NT30KLT in my RV. The motor started having a faint squealing noise on startup that went away when the unit warmed up.
I disassembled the unit, but was not able to get the motor out as I could not get the squirrel cage fans off of the motor shafts. Instead, I dribbled oil on the shaft ends and set the motor in a shaft-vertical orientation one way, and then turned it upside down the other way to allow oil to run down the shaft into the bearings.
I put the unit back together and it no longer squeals. I'm not sure how much oil I was able to deliver to the bearings so I don't know how long my fix will last, but the squeal is gone for a year now and the fix was free.
I'm not sure what the replacement furnace is for the NT30 but if you have pulled the unit enough to get at the fan assembly then you have probably realized you can also replace the entire furnace yourself. They cost about $500.
Steve
