Tilt Gear

[genesis08]

Having problems with my OMC Stringer outdrive tilt mechanism!!,For some reason it will not go up or down.I put in a new tilt motor and also have checked the the blow coupling and worm drive.I have striped the housing itself but to no avail,changed oil etc.all I can really tell you is it makes the effort to move up and down with a CLUNK but will not complete the cycle.Any suggestions would be greatly appreaciated...Regards Brian..........