Re: Ultramatic transmission problems

Posted by Ross On 2023/11/14 21:47:08

My guess is that the sprag clutch inside the convertor is not taking up its load as you coast to a stop. If it does not grip and hold the stator turbine still, the convertor becomes remarkably inefficient and will hardly even move the car with high revs. Some how when switched off the sprags regain their grip and you can move off.

For trouble shooting purposes I assume you have tried the High, Drive and Low positions. It would be good to plumb a gage into the high range port mentioned in the sevice manual to be certain it is getting pressure when you attempt to take off in high. If you get suitable pressure there and no forward motion on takeoff, then it is almost certain the sprag clutch is not holding.