Re: ultramatic

Posted by Ross On 2015/3/10 5:28:38

Don't believe there is any HD spring for that.

Twin Ultramatics sticking in park is a plague coming from 3 typical sources:

On 55s, the geometry of the linkage is unfavorable resulting in very little leverage at the trans to pull it out of park. There is a service bulletin about that which I'll try to find later.

Second there is a little roller that pushes the parking pawl up into place. The widget that holds the roller is often distorted. More importantly and often overlooked is the little stop pin that is to keep the roller from traveling too far as you pull the mechanism up into park. These pins bend or break and the mechanism goes over center. When this happens the car will only come out of park if there is zero parking load as the roller must push the pawl into tighter engagement before it can actually release it. The pin can be replaced with tranny in the car, but the tailshaft must come off.

Third is a category of damaged components, typically a bent operating shaft, pawl with burs, damaged parking gear.

Packard issued a bulletin about grinding a chamfer on the control valve to alleviate the problem. They were mistaken--that is pretty well never the problem.