Guest cm64d Posted October 14, 2009 Share Posted October 14, 2009 I'm in the process of restoring a 1931 Chrysler CM6. The transmission grinds at any speed when upshifting to any gear. No problem when starting out. I can pull it it into first, engage the clutch with no hint of grinding. The clutch disc looks new and pressure plate looks & functions good (like it may have been changed before I got the car). No noise from the externally greased through out bearing. The owners manual mentions a smooth shift feature. I've seen ads for Desoto's that mention this also. I'm suspcious of this, but want info on how it works before tearing into the tranny. Does anyone out there have knowledge on this smooth shift feature?:confused: Link to comment Share on other sites More sharing options...
keiser31 Posted October 14, 2009 Share Posted October 14, 2009 I would be interested in an answer for you also as my 1931 DH6 has the same malady...and the same transmission as the CM6, I believe. The "silent shift" feature may have only come with the cars equipped with free wheeling. Link to comment Share on other sites More sharing options...
Guest cm64d Posted October 14, 2009 Share Posted October 14, 2009 My brother had a '32 dodge with free wheeling. It wouldn't shift at all in FW. I'll hunt up the owners manual and re-read about that feature. I don't remember FW being mentioned. Link to comment Share on other sites More sharing options...
keiser31 Posted October 14, 2009 Share Posted October 14, 2009 A lot of guys on this forum talk about "double clutching"....I am ashamed to admit that after all these years around old cars, I still don't know exactly what that means or how to do it. I cannot imagine that Chrysler wanted people to do that from the start. Maybe your problem (and mine) is the gear oil level being too low. It seems that if I shift slowly or hesitate a bit between shifts, it goes through the gears quieter. Link to comment Share on other sites More sharing options...
John Gelfer Posted October 14, 2009 Share Posted October 14, 2009 I believe you do have to double clutch. Clutch once to pull it out of gear, and into neutral. Clutch again and push it into the next gear. Takes a little practice. Upshifting is much easier than a smooth downshift, at least for me. I just got babtized in the "double clutch shuffle" this summer when I got my 1928 Gardner running. Link to comment Share on other sites More sharing options...
keiser31 Posted October 14, 2009 Share Posted October 14, 2009 I believe you do have to double clutch. Clutch once to pull it out of gear, and into neutral. Clutch again and push it into the next gear. Takes a little practice. Upshifting is much easier than a smooth downshift, at least for me. I just got babtized in the "double clutch shuffle" this summer when I got my 1928 Gardner running.John is correct. I just talked with a friend who owns two similar cars and he said anything with gears like the ones in those transmissions need to be double clutched or shifted REALLY slow or you will get that chinkering noise. Link to comment Share on other sites More sharing options...
Guest martylum Posted October 14, 2009 Share Posted October 14, 2009 I am driving a 1930 Desoto and a 1933 Chrysler both with 1933 transmissions and the Chrysler with free wheeling.You should not have to double clutch if the synchronizers in your trannies are working properly and shifting should be easier in a tranny with free wheeling when free wheeling is engaged as the rear axle does not drive the tranny mainshaft when you back off on the throttle. If you have F. W. there will be a push-pull handle under the dash labeled freewheeling.You do however have to take your time shifting up and down the gears and with first gear not being synchronized which means do not shift to first unless you are stopped or know how to double clutch.. I keep the Chrysler out of free wheeling to have engine breaking and I don't have the vacuum clutch hooked up which requires the car to be in free wheeling.If shifting is still a grinding affair with easy slower shifts you might have troubles with worn shnchronizers.Martin LUm Link to comment Share on other sites More sharing options...
hchris Posted October 14, 2009 Share Posted October 14, 2009 All true; until the invention of syncromesh in manual transmissions gear changing was, and still is, an aquired skill; double clutching was just a part of it. Put quite simply, what you are trying to do is match the speed of the engine input drive to the rear wheel out put drive, obviously whilst in motion these speeds differ significantly. Perhaps the best advice for smooth changes is to go through the actions slowly and anticipate that a cold transmissission will make these actions even more difficult; so clutch in - move gear lever through neutral - pause - then select next gear.One other factor is weight or grade of trans oil, this can have quite an effect on how smoothly the gear changes occur, I would start with the recommended grade and be prepared to go up a grade or two dependending on the wear in the transmission. Link to comment Share on other sites More sharing options...
John Gelfer Posted October 15, 2009 Share Posted October 15, 2009 Is it true that a 120 wt oil will make for quieter shifting than 90 wt? Link to comment Share on other sites More sharing options...
Larry Schramm Posted October 15, 2009 Share Posted October 15, 2009 I agree with the type of fluid. My old truck says 600 weight gear lube. Even new manual transmissions have multiple types of fluid/lube. Link to comment Share on other sites More sharing options...
hchris Posted October 15, 2009 Share Posted October 15, 2009 Is it true that a 120 wt oil will make for quieter shifting than 90 wt?In an ideal world the answer would be yes, however the colder the oil gets the more difficult it becomes to shift due to increasing viscosity.So if you live in a cold environment expect difficult shifting until the oil reaches correct operating temperatures.As to the original thread; I would renew the bearings and syncromesh cones if you are carrying out a restorartion, because if you have problems now it will only get worse. Link to comment Share on other sites More sharing options...
Guest cm64d Posted October 15, 2009 Share Posted October 15, 2009 When in doubt, read the instructions. The owners manual recommeds S.A.E. #160 above freezing or you may have shifting problems. I had put SAE 90 in thinking I would freshen up all lubes. I'll try it next spring as I'm going through the brakes this winter. Thanks you all for the input and help! Link to comment Share on other sites More sharing options...
Guest ken8824 Posted October 15, 2009 Share Posted October 15, 2009 You make the newbie here feel good-I got my '30 CJ in August and have a time learning to change gears without grinding-double clutch is the only thing that I have found that works. Will be watching for other suggestions. Link to comment Share on other sites More sharing options...
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