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| | | | Joined: Oct 2008 Posts: 121 Shop Shark | | Shop Shark Joined: Oct 2008 Posts: 121 | Swapped out the 3 speed in my 55 for a supposedly good runner only to find out it is making noise in 3rd and now my speedo does not work, so not much further ahead. My original was dropping out of 3rd under load. Any one know where to get a rebuild kit or what the transmission designation is?
Thanks
1955 Chevy 3100
| | | | | Joined: May 2005 Posts: 487 'Bolter | | 'Bolter Joined: May 2005 Posts: 487 | Check with Jim Carter's. He's got trans parts listed in his catalog. Your local manual tranmsission shop may also have some parts to fit. Mine in Fort Worth does. regards, Leon | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | For gaskets and seals, try Napa. But if you need hard parts, try Northwester Transmission Parts. They deal in vintage transmissions. I have dealt with them personally, very good service. 4 Speeds by Darell might be another...n with Darell as well, very knowlegable. Just from the description, sounds like a detent has gone sour, whcih will make it jump out of gear. The speedo is most likely an unreleated problem, could be a stripped speedo drive gear, plastic gears are not uncommon in thise, or a bad cable. Your trans should be an SM318.
Last edited by LONGBOX55; 07/13/2009 1:16 AM. Reason: extra information added
Bill Burmeister
| | | | | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 | LONGBOX55, Is the detent a part inside the transmission housing? If it is, is it shown in this diagram (it's a car transmission but the part name/location should be the same). My 54 3-speed also jumps out of third, but it does this when I am cruising. I have tried adjusting the levers that connect to the arms on the shift box in the engine compartment, on the steering column. These seem to be centered nicely. I have found a place that sells shift forks (4.303 in the diagram) for 2nd-3rd, 48-61 trucks. By any chance is this the detent? Thanks, Tim | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | The detent is the Ball abd Spring, parts # 8-899 and 8-807 respectiely. Could have a weak or briken spring, I doubt that the ball itself is worn, but that is possible, too. There is also a possibility that the shift cover is worn, but again, I find that unlikely. The SM 318 is identical, exept it is open drive.
Bill Burmeister
| | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | Tim - I think the detent Bill means is the spring and ball between the cover and the fork assy's - it presses into a depression in the cover I believe, spring may be weak or ball groove worn .... my experience with jumping out of 3rd at cruise is bad syncro - happened with my 57 with slight deceleration, as might be caused by minor variations in the road grade [he beat me  ] Bill
Last edited by red58; 07/13/2009 2:07 AM.
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