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| | | | Joined: Jul 2009 Posts: 367 'Bolter | | 'Bolter Joined: Jul 2009 Posts: 367 | I have a 59 with a sm420, ran in to a guy that has one out of a 52. was wondering if it will fit in mine. It was from a closed drive shaft truck mine is open and has the emerg brake on the back. mine has a lot of noise in second and am wondering if the parts will interchange . price is probably right on the trans. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Always good to have a spare, however, probably more work than to just rebuild existing 420. Novak in Salt Lake City has all the parts you will need.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | Both bolt to the bellhousing the same, all SM240's do.
I believe that you can mix and match output parts and convert one to the other type of driveline, but I have not done it.
They're so cheap and plentiful I'd just find one that actually fits.
Grigg | | | | | Joined: Aug 2017 Posts: 1 New Guy | | New Guy Joined: Aug 2017 Posts: 1 | here is information from Novak's website. Looks like the difference is a weep hole on the 52.
1947-1953:
No ribs on the case
Grooved worm on the input shaft instead of neoprene seal
Synchro rings all differ from each other. 1st-2nd synchro ring is bronze
Weep hole at 6 o'clock on the bearing retainer snout
Six digit casting number on the case, usually like "59xxxx" e.g., 591665.
1954-1963:
Same as previous but uses a neoprene input oil seal
No weep hole at 6 o'clock on the bearing retainer snout
1964-1967: Same as previous except
1st-2nd synchro ring is aluminum and 3rd-4th synchro rings are identical to each other
Seven digit casting number usually like "37xxxxx", "38xxxxx" or "39xxxxx"
1968-1981: Military Con-Diesel version. Features the strongest case and optimized internals. Usually equipped with unique top cover, but can be converted to standard top-shift control. | | |
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