what you need to do is pay the money to join tow411.com

I belong to the site and there is a few members with pictures of the same manley wrecker unit that you have.

They can fill you in,

The site only allows you to post pics and questions if you are a member. Otherwise your posting gets deleted.

It is worth the cost to get the right info

Poets Seat Auto
Appraisals, Parts, Service
Past: General Motor's Master Technician
Member: Northeast Chevy/GMC Truck Club
Phone Number: 413.774.5856
Collector of: 1951 Army Chevy Burb barn door,53 GMC COE,two 1934 Chevy Truck,1935 Chevy Army Truck.1950 Gmc Suburban clamshell these are just my chevy/gmc trucks.