You can also pull the old axle and take it to your nearest Dexter axle dealer. The dealer will take the critical measurements. They can order you the axle directly.
Take these documents with you for reference. The differnce between a #10 and #11 axle will be size of the axle tube, spindle size and brake drum size. Also look at the tag on the side of the trailer. This will have the axle weight rating. You will need this number when ordering a new axle.
PM me if further info needed. I have been thru this a few times.
Steve, Christy, Anna and Scout (Border Collie)
1994 30'11" Excella - rear twin
2009 Dodge 2500, 6 Speed Auto, CTD, Quad Cab, Short Bed
Hensley with adjustable stinger
WBCCI # 3072
AIR # 6035