I think that for a 2008 RV that the motor will have a phenolic housing over the motor gears. I don't know anyone that has identified those motors as being window lift motors or at least not for a Ford. They may be available from Amazon but none of you have given a specific part number. How about an little real help here.
APOLOGY; Some of the step motors listed on Amazon are Ford specific.
COMMENT: I suggested and feel it is fair to ask the OP to state what brand of steps, mfg and any part number on the motor. Also is the gearing on the motor in an aluminum or phenolic casting. Who really manufactured the steps. More later I'm being called by she who must be obeyed. (Edit) All this information would have helped. I believe in 2006 that Kwikee changed from Ford type lift motors and went to AM Machinery step motors, they were very helpful at AM Nachinery. Then Kwikee sold to US Power Gear and they sold to Lippert. I would bet that Lippert is still using the AM Ind motors. Perhaps Chris Bryant will step in if he knows.
My point is if you bought a motor from Amazon, which one for what set of steps manufactured in what year. Maybe yours are the same as the OP.
By the way, the 888 manual is still the manual for the Ser. 32 steps and others.