Anyone building SM420's near Pittsburgh? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67K10longbed · 03-15-2022, 09:51 PM

I think I found the main shaft and coupler to fix my SM420. I have it partially apart , but without a press I am stopped. I am not sure how to get it apart from here. I would guess the 3rd needs pressed off? I am going to do some more reasearch , but in the meantime is there anyone in Pittsburgh , Pa area that rebuilds these? This is where I am with the trans.

**MJN** · 03-16-2022, 08:08 AM

You need to remove the entire main shaft assembly to remove the gears. If you have a service manual it has clear steps on disassembly. I rebuilt mine last spring with no special tools or issues, I used a rebuild kit from Novak Adapters.
If you need a service manual you can download a pdf copy here
http://67-72chevytrucks.com/vboard/s....php?p=5781194

**HO455** · 03-16-2022, 08:28 AM

As MJN stated the SM420 is an easy transmission to rebuild and Novak is a great vendor.
Since your already that far might as well go all the way. This video link may be helpful.

And Welcome Aboard.

https://youtu.be/6imX-_msbo8

67K10longbed · 03-16-2022, 09:08 AM

Thanks, I will take a look.

03-15-2022, 09:51 PM	#1
67K10longbed Registered User Join Date: Mar 2022 Location: Pittsburgh Posts: 16	Anyone building SM420's near Pittsburgh? I think I found the main shaft and coupler to fix my SM420. I have it partially apart , but without a press I am stopped. I am not sure how to get it apart from here. I would guess the 3rd needs pressed off? I am going to do some more reasearch , but in the meantime is there anyone in Pittsburgh , Pa area that rebuilds these? This is where I am with the trans. Attached Images

03-16-2022, 08:08 AM	#2
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 3,051	Re: Anyone building SM420's near Pittsburgh? You need to remove the entire main shaft assembly to remove the gears. If you have a service manual it has clear steps on disassembly. I rebuilt mine last spring with no special tools or issues, I used a rebuild kit from Novak Adapters. If you need a service manual you can download a pdf copy here http://67-72chevytrucks.com/vboard/s....php?p=5781194 __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com

03-16-2022, 08:28 AM	#3
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,350	Re: Anyone building SM420's near Pittsburgh? As MJN stated the SM420 is an easy transmission to rebuild and Novak is a great vendor. Since your already that far might as well go all the way. This video link may be helpful. And Welcome Aboard. https://youtu.be/6imX-_msbo8 __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

03-16-2022, 09:08 AM	#4
67K10longbed Registered User Join Date: Mar 2022 Location: Pittsburgh Posts: 16	Re: Anyone building SM420's near Pittsburgh? Thanks, I will take a look.

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