Re: ultramatic tranny cooler flow

Posted by Ross On 2014/3/20 20:38:29

Two things come to mind. The first is that the convertor inlet valve is stuck, or part of it is in backward, etc. That is the upper left valve in figure 36 on page 12 of the service manual.

The second--and I had this happen to me once--is that there was a hole not punched in the bell housing-to-case gasket.

The path of the fluid from the valve body into the convertor passes through that gasket and into a passage that goes to an annular groove on the outside of the convertor bushing. It then goes into the convertor through the 4 holes that are drilled in the convertor stub shaft.

In drive you should have 70-80 lbs before lockup, 8-15 afterward.

An old Packard engineer explained to me once that Packard charged their convertor to such a high pressure to avoid cavitation and noise during hard acceleration. The pressure drops when direct engages to prevent countering the pressure on the direct clutch piston, and because at that point cooling of the convertor is not needed. At kickdown the convertor is again charged to high pressure to push the direct clutch piston back away from the clutch disk. That is why most Ultras do not have such an instantaneous kickdown out of direct--it takes a fraction of a second to charge the convertor to a higher pressure and push the piston back.