Ramy,
If the effort to pull the release, seems to be less, you may have a broken spring. There are two return springs, one on each side of the Tost release. For ground towing, I'd get a chain that measures 1/4" thick X 1" X 1.5".............the cost of new Tost rings ($44.00) means they are used forever........I remember seeing one that was older than dirt and had failed at 2 places, 180 degrees apart.
Hope this helps,
JJ