I have a friend with a '66 Pontiac LeMans. His car has the 2-speed Tempest Turbine (Pontiac name for the Buick ST-300) and has asked me for help. The problem is this: His transmission won't shift up or down automatically. It starts off in Drive and stays there. Manually moving the shift lever to Low forces it to downshift, but if the lever's in Drive it won't go to Low, even at idle or full-throttle. Any ideas? Clogged governor? Bad modulator?
I would check to see if the modulator will hold vacuum. I wasn't giving my ST-400 good vacuum, and it really wasn't concerned with shifting out of first gear until I corrected the problem.
Thanks for the suggestions - I'll give those a try. I did check to make sure the vacuum modulator wasn't leaking. However, I did not check to see if the line was plugged. I'll also test the kick-down switch. I'll post the results.
