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| | | | Joined: May 2010 Posts: 144 Wrench Fetcher | | Wrench Fetcher Joined: May 2010 Posts: 144 | I have a fellow that wants to buy the 4 speed (with granny gear) that was original in my ’53 Chevy 3600. He has asked me who the manufacturer was and the model name of the transmission. He asked about Saginaw. Can anyone help out here from this limited information?
Thanks
John
| | | | | Joined: Jun 2009 Posts: 2,201 Shop Shark | | Shop Shark Joined: Jun 2009 Posts: 2,201 | Hey John, It's maybe a SM420, Does it look like this? | | | | | Joined: May 2010 Posts: 144 Wrench Fetcher | | Wrench Fetcher Joined: May 2010 Posts: 144 | I don't have it with me as I am having a new T-5 and rebuilt 235 installed about 2 hours away. I'll check when I go get it. I hoped that the '53s were all the same.
John | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | More information on the Muncie SM-420 This was the only 4-speed transmission available from the factory on any 1953 Chevrolet truck. | | | | | Joined: Jun 2009 Posts: 2,201 Shop Shark | | Shop Shark Joined: Jun 2009 Posts: 2,201 | I said maybe because it may not be "from the factory". The Jeep guys love those SM420 transmissions. Check your local want ads if you need to set a price on it. | | | | | Joined: May 2010 Posts: 144 Wrench Fetcher | | Wrench Fetcher Joined: May 2010 Posts: 144 | | | | | | Joined: Jun 2009 Posts: 2,201 Shop Shark | | Shop Shark Joined: Jun 2009 Posts: 2,201 | The answer lies in the links provide by Tim and myself. Click on the Blue words in the posts, they are links to helpful information.
Last edited by FriedGreenTmater; 08/18/2010 5:46 PM.
| | | | | Joined: Jul 2001 Posts: 3,887 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Jul 2001 Posts: 3,887 | GM made'em all - if the guy is looking for a "saginaw 4 speed" and thinking one might be in a 53 truck, he doesn't really know what he's looking for  Bill | | | | | Joined: May 2010 Posts: 144 Wrench Fetcher | | Wrench Fetcher Joined: May 2010 Posts: 144 | He said that he was indeed looking for a SM-420. Now my question gets to a new level. My truck is a 3/4 ton and has an enclosed front propeller shaft. When that is removed from the back of the transmission, it would appear that for the transmission to be used for "open drive shaft" applications, it would need a different universal front flange and oil seal. Am I correct in assuming that the oil from the transmission presently flows back and fills or lubricates the enclosed front propeller shaft, or is the rear oil seal the same for all of these SM-420s and all that would be needed would be a different universal front flange?
Thanks
John | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
The transmission's rear cover for the enclosed driveshaft would need to be replaced with the rear cover for an open driveshaft.
There is a seal in the open-driveshaft rear cover.
| | | | | Joined: May 2010 Posts: 144 Wrench Fetcher | | Wrench Fetcher Joined: May 2010 Posts: 144 | I take it from the shop manual ( http://chevy.oldcarmanualproject.com/1929_54chevyparts/04/220.HTM ) that it is called "transmission rear bearing retainer 4.317". It appears that an oil seal goes into it and then the universal joint front flange passes through the oil seal. Do you know if the universal front flange is the same for my enclosed system or different for the open drive shaft? Thanks for all of the help here. John | | |
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