Hello.

I've been trying to figure out what line pull rating
my Tulsa 18G worm gear winch might have.  Nowadays
it seems to be (according to web pages) a 20.000lbs
winch, but during WWII it was only a 10.000 winch.
Mine has mechanical fork like system (a sliding block
on the drive axle, looks bit like a butterfly with
wings spread) which engages the drive axle to the
reel.

Gearbox is round type like here:

http://www.chars-francais.net/kithobbyist/m3gmc1.htm

(see the last picture showing winch from upward)

Nowadays gearbox seems to have more square appearance:

http://www.ryanhyd.com/oldhtml/tulslow.htm

The winch has "18G" and a serial number stamped on
top of the gear housing.  If it's original equipment
on my truck, then it should be from the sixties.

Does anybody know?