jackofalltrades70 Posted January 21, 2018 Share Posted January 21, 2018 Does anyone have a manual for these manual 3 speed gm transmisions? I was having a terrible time with 2nd gear grinding and not going into gear. The Buick shop manual doesn’t go far enough in detail. I am worried about the space seen in the picture below. Link to comment Share on other sites More sharing options...
jackofalltrades70 Posted January 25, 2018 Author Share Posted January 25, 2018 Any help here? Has anyone had their manual tranny out of their 46-48 Buick? Link to comment Share on other sites More sharing options...
Bill Stoneberg Posted January 26, 2018 Share Posted January 26, 2018 Yes, but I have no shop manual for them. I always had to double clutch between the gears. I think the syncros were gone and never found any. Yours looks like mine looked. 1 Link to comment Share on other sites More sharing options...
DonMicheletti Posted February 5, 2018 Share Posted February 5, 2018 GM used that same design transmision for years on the larger cars. There is supposed to be a snap ring at the front of the second gear idler to hold it back against that sholder at the left of your photo Link to comment Share on other sites More sharing options...
avgwarhawk Posted February 8, 2018 Share Posted February 8, 2018 (edited) It appears to me the synchro is missing? This is my 54 3 speed. The transmission are basically the same. Minus maybe a synchro set up and gear ratios. I took mine apart as 2nd was grinding. Found a broken synchro drum. Sourced one on ebay. Is the 47 manual synchro for 2nd and 3rd? Edited February 8, 2018 by avgwarhawk (see edit history) Link to comment Share on other sites More sharing options...
jackofalltrades70 Posted February 11, 2018 Author Share Posted February 11, 2018 On 2/8/2018 at 4:36 PM, avgwarhawk said: Is the 47 manual synchro for 2nd and 3rd? Yes the sycro is for 2nd-3rd. The syncro is circled in this picture. The second gear seems to be sliding away from the syncronizer back. Link to comment Share on other sites More sharing options...
jackofalltrades70 Posted February 11, 2018 Author Share Posted February 11, 2018 If that gear would stay forward, it couldn’t slip off of the syncronizer pack Link to comment Share on other sites More sharing options...
avgwarhawk Posted February 12, 2018 Share Posted February 12, 2018 On 2/10/2018 at 7:15 PM, jackofalltrades70 said: Yes the sycro is for 2nd-3rd. The syncro is circled in this picture. The second gear seems to be sliding away from the syncronizer back. Different set up than mine from the looks of it. I have two synchro drums for 2 and 3. At the bottom sump/drain plug area , is there bits of metal from a snap ring or the like that has failed? Link to comment Share on other sites More sharing options...
DonMicheletti Posted February 13, 2018 Share Posted February 13, 2018 The larger and smaller transmissions are entirely different designs on the synchros and 2 to 3 shifting drum. 1 Link to comment Share on other sites More sharing options...
DonMicheletti Posted February 13, 2018 Share Posted February 13, 2018 The 2 transmissions shown, one is the larger series, while the video is of the smaller transmission. 1 Link to comment Share on other sites More sharing options...
jackofalltrades70 Posted February 13, 2018 Author Share Posted February 13, 2018 Yes, mine is out of a Roadmaster. I havent taken the one out of my super yet as I knew it was different. Any idea what years would be the same? 39-53? 1 Link to comment Share on other sites More sharing options...
jackofalltrades70 Posted March 31, 2018 Author Share Posted March 31, 2018 Took the transmission to an goodoleboy, backwoods mechanic from years ago. Nowadays, all he does is rebuild older engines and the such. He took the tranny apart, found that someone had installed a snap ring, that holds the gears forward, was too large to hold in the groove. Wrong diameter. Tranny is back together and should have it back Tuesday or so. Have to send the clutch disc and motor/tranny mounts to Bob’s and get the new ones back. Probably another week or so....... 1 Link to comment Share on other sites More sharing options...
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