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1971 Mark III Shifting Issues

Hi Bill

I have a problem whit my automatic transmission of my 1971 Mark 3. It looks like my transmission will not shift in gear properly? If I drive the car my gear will not shift up like it is supposed to do?? It will only shift up when I go down on the throttle, as soon as I let the throttle go and the rpm goes down it will shift into the next gear. I have to do this with all gear's. I also sometimes (lets say always !) have to move the gear lever up en down a couple of times to get the best position to go in to his drive gear. I have checked my vacuum hose and it has vacuum on it?? I hope you have some answers for me.


The Netherlands


Hello Ray -

Welcome to the Lincoln Land blog. If I am understanding you correctly I think that you should first check the vacuum line which is located at the Modulator valve under the car at the right rear of the transmission. The steel line and rubber hose should not be damaged or deteriorated in any way and adequate engine vacuum should be available there with NO evidence of transmission fluid in the lines. Any internal leaks at the Modulator will require that a new Modulator valve will be needed. Secondly the transmission "kick-down" Rod should be inspected (with the engine OFF) for proper operation at full throttle position of the carburetor and for a return to the idle position (by a separate spring located at the carburetor) when the carburetor linkage is allowed to return back to the engine idle position. If this rod does NOT return as designed, the transmission is locked in a full throttle position. This Rod is located at the left side of the carburetor and connects to the transmission via linkage at the left side of the transmission. The above two items are important controls for the shifting of your transmission and are the first items that we at Lincoln Land would be examining on a vehicle with a shift problem such as you describe. As far as a problem with shifting into DRIVE is concerned, you should check and adjust your manual shift linkage as required as well as inspect for loose bushings etc., in this linkage. I hope that the above leads you to a speedy repair and if you should require any parts or further advice etc. we are at your service.