53 In PA Posted May 31, 2019 Share Posted May 31, 2019 1953 Desoto With Fluid Drive transmission. Has run like a champ for years, but lately it seems to not want to shift up to the higher gear after the car warms up. Shifts fine for a few miles while cold, but then won’t upshift when releasing the throttle. I have checked all fluids, including trans fluid inside car under carpet. Anything else to easily check? Or any thoughts in what the issue might be? Thanks in advance . Link to comment Share on other sites More sharing options...
c49er Posted May 31, 2019 Share Posted May 31, 2019 Too high of Idle speed possibly.... needs to be around 450 RPM... Governor points could be dirty too. Link to comment Share on other sites More sharing options...
53 In PA Posted June 1, 2019 Author Share Posted June 1, 2019 Interesting you mention idle speed. Sometimes when the sticking occurs, the engine idles very high in neutral. Link to comment Share on other sites More sharing options...
c49er Posted June 1, 2019 Share Posted June 1, 2019 Proper idle speed being slow enough lets the direct speed blocker ring sync up with the input shaft.... causing the up-shift. Link to comment Share on other sites More sharing options...
53 In PA Posted June 1, 2019 Author Share Posted June 1, 2019 Odd that it’s fine until car warms up a bit. Is adjusting the idle done at the carb? Link to comment Share on other sites More sharing options...
keithb7 Posted June 13, 2019 Share Posted June 13, 2019 Cold oil is thicker. Hot oil thinner. If oil pump or shift piston is starting to wear, it’ll be easier to build and hold pressure with cold oil. The tranny needs oil pressure to overcome spring pressure to shift. When it does happen to up shift, does it easily down shift when slowing down? Consider an oil pressure test. Instructions are readily available. Link to comment Share on other sites More sharing options...
53 In PA Posted July 10, 2019 Author Share Posted July 10, 2019 Yes, when cold it easily downshifts as well. Link to comment Share on other sites More sharing options...
c49er Posted July 10, 2019 Share Posted July 10, 2019 Carb automatic choke slow to open holding the fast idle cam on too long.... Link to comment Share on other sites More sharing options...
53 In PA Posted July 12, 2019 Author Share Posted July 12, 2019 How to fix that? Link to comment Share on other sites More sharing options...
61polara Posted July 13, 2019 Share Posted July 13, 2019 It's a long shot, but since this is a new problem after years of diving it, look for something that has changed. Is a motor mount going bad that has shifted the engine some and increased the idle speed because of the movement? Link to comment Share on other sites More sharing options...
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