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| | | | Joined: Mar 2000 Posts: 18 Member | | Member Joined: Mar 2000 Posts: 18 | I have a 4spd tranny that is suppose to be from a 48-54 chevy truck and I would like to know exactly which year. the casting number on the driver's side is 591665.
thanks, Ken | | | | | Joined: May 2001 Posts: 1,904 'Bolter | | 'Bolter Joined: May 2001 Posts: 1,904 | I have the same casting number on my 4 speed in my '48 3/4T. I know the engine wasn't original but I suspect the transmission is. I don't know about casting date numbers on transmissions but I have "01 8" above the 591665. Jan. '48???
1948 3/4-Ton 5-Window Flatbed Chevrolet 34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
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#2932 01/29/2003 11:03 PM | Joined: Aug 2001 Posts: 258 'Bolter | | 'Bolter Joined: Aug 2001 Posts: 258 | Daddeo,
Can't help you with casting numbers, but if is set-up for an enclosed u-joint and torque-tube, it's definitely pre-54.
Frank McMullen
1941 Chevy dump truck
1949 GMC 100 pick-up
1954 Chevy 3600 pick-up
1955.1 4400 dump truck
1941 De Soto & other MoPars
1928 Model A F**D Special Coupe
| | | | | Joined: Dec 2002 Posts: 86 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2002 Posts: 86 | I have a 48 3/4 ton. But it does not have a torque tube it has a two piece drive shaft. Does that mean it was swaped over ? It looks like it belongs there.
47.5 Loadmaster 5 window
48 Chevy 3600
69 GTO convertible
| | | | | Joined: Jun 2000 Posts: 454 Shop Shark | | Shop Shark Joined: Jun 2000 Posts: 454 | AD 3/4 tons did not use the enclosed drive shaft. Drive shafts are exactly as you describe. Can't help with the tranny casting number.
Jeff Nelson
"Beer is proof that God loves us and wants us to be happy." - Benjamin Franklin
"Always do right. This will gratify some people and astonish the rest." - Mark Twain
| | | | | Joined: Aug 2000 Posts: 346 Shop Shark | | Shop Shark Joined: Aug 2000 Posts: 346 | daddeo,
On top of the transmission immediately behind the shift tower is a flat spot about 6 x 8 inches. On that space should be some cast in numbers with the foundry date code.
My '38 1-1/2 ton's have the following codes:
J 21 7 -> September 21, 1937
F 7 5 -> June 7, 1935 or 1945
The first number is from the truck with the original engine in it that doesn't appear to have ever been out of the truck.
In a recent publication from the National Corvette Restorers Society, there is an article about foundry marking on 'Vette intake manifolds. The tag used to make the date code indicates which SHIFT in foundry made the part by the shape of the screw heads holding the tag in place. Two flat heads -> 1st shift, 1 round head, 1 flat head -> 2nd shift and 2 round head for 3rd shift.
This was used at the Chevrolet Saginaw Foundry.
'38 Chevy 1-1/2 ton
'49 Chevy 1/2 ton
'54 Chevy 6400 2 ton
'55.2 GMC 3/4 ton
'56 GMC 1-ton
No Room Left in Shop
| | | | | Joined: Nov 2000 Posts: 1,966 'Bolter | | 'Bolter Joined: Nov 2000 Posts: 1,966 | Novak Adapters has a great website with a really informative article about the SM420 trans. Try http://www.novak-adapt.com/knowledge/sm420.htm for serial no. codes, etc. I had a 50 3/4 ton with 2 piece drive shaft. The trans. tail shaft had the 4-bolt flange for that ball shaped u-joint housing (just like a 1/2-ton) and the front drive shaft was torque-tube back to the carrier bearing. The rear shaft was open.
Professional Novice
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