6066 (1960-1966) GMC Truck Club Bitcoin now accepted here! 
Pay Dues
Pay Dues or become a Site Supporter
 



Go Back   6066 (1960-1966) GMC Truck Club > 6066 GMC Truck Club Forum > Transmissions and Rear Ends
#Sponsored

Transmissions and Rear Ends Three on the tree or four in the floor? Shift it all here.

Reply
 
Thread Tools
  #1  
Old October 20th, 2020, 05:15 PM
IslandGMCguy IslandGMCguy is offline
Junior Member
 
Join Date: Oct 2020
Location: Victoria, British Columbia
Truck: 1966 GMC 910 1/2 ton fenderside (Canadian)
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
IslandGMCguy is on a distinguished road
Default What transmission is this?

I have my 1966 GMC 910 (Canadian) 1/2 ton pickup at a transmission shop for having the transmission rebuild. They told me it was a rare and unusual transmission in it?? It is a 4 speed manual on the floor. They said they were having a lot of problems finding internal parts for it. They told me the trans was a MNNP420 transmission. I have never heard of this and can’t find any info online either. Anyone know what this is???
Reply With Quote
  #2  
Old October 20th, 2020, 06:25 PM
FetchMeAPepsi's Avatar
FetchMeAPepsi FetchMeAPepsi is offline
-= Dues Paid =-
 
Join Date: Jan 2013
Location: Edmond, Ks
Truck: 1962 4x4 GMC CECILIA
Posts: 1,781
Thanks: 21
Thanked 4 Times in 3 Posts
Rep Power: 570
FetchMeAPepsi is a glorious beacon of lightFetchMeAPepsi is a glorious beacon of lightFetchMeAPepsi is a glorious beacon of lightFetchMeAPepsi is a glorious beacon of lightFetchMeAPepsi is a glorious beacon of lightFetchMeAPepsi is a glorious beacon of light
Default Re: What transmission is this?

Try looking at SM420 and see if the trans matches yours. I'm pretty sure they don't know butt from elbow at that transmission shop. You can rebuild them pretty easily on your own if they bugger it up. Sm420 was a very popular trans.
__________________
Step by steps:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Some people are like slinkys. Not worth much but funny as heck when pushed down stairs.
__________________
If the women don't find you handsome, they should at least find you handy.
Reply With Quote
  #3  
Old October 20th, 2020, 06:31 PM
Funky61's Avatar
Funky61 Funky61 is offline
-= Dues Paid =-
 
Join Date: Jan 2013
Location: Corona, CA
Truck: 1961 Suburban 1962 GMC Utility
Posts: 1,167
Thanks: 11
Thanked 8 Times in 5 Posts
Rep Power: 421
Funky61 is just really niceFunky61 is just really niceFunky61 is just really niceFunky61 is just really niceFunky61 is just really niceFunky61 is just really nice
Default Re: What transmission is this?

Novak has the kits for it and I always thought they were fairly common

https://www.novak-adapt.com/catalog/...s/sm420-parts/
__________________
1961 GMC Suburban 305A Overdrive
1962 GMC Utility 305D
Reply With Quote
  #4  
Old October 21st, 2020, 12:29 AM
Ed Snyder's Avatar
Ed Snyder Ed Snyder is offline
-= Dues Paid =-
 
Join Date: Jan 2013
Location: Medford, Oregon
Truck: 1962, 1967
Posts: 889
Thanks: 0
Thanked 5 Times in 3 Posts
Rep Power: 351
Ed Snyder has a spectacular aura aboutEd Snyder has a spectacular aura aboutEd Snyder has a spectacular aura aboutEd Snyder has a spectacular aura aboutEd Snyder has a spectacular aura aboutEd Snyder has a spectacular aura about
Default Re: What transmission is this?

Quote:
Originally Posted by IslandGMCguy View Post
I have my 1966 GMC 910 (Canadian) 1/2 ton pickup at a transmission shop for having the transmission rebuild. They told me it was a rare and unusual transmission in it?? It is a 4 speed manual on the floor. They said they were having a lot of problems finding internal parts for it. They told me the trans was a MNNP420 transmission. I have never heard of this and can’t find any info online either. Anyone know what this is???
If it's actually an SM420, and not an "MNNP420", then it is neither "rare" nor "unusual" as your shop claims. They were installed in thousands, if not millions, of trucks from 1947 to 1967.

Good luck with your rebuild!
__________________
Ed Snyder
Medford, Oregon
1962 1000 Pickup 401M & Muncie 318 with overdrive
1962 K1000 Suburban 401M & SM420
1967 CM1500 pickup 351E & NP435
Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Transmission??? GTS61 Transmissions and Rear Ends 4 February 27th, 2019 04:10 AM
Re: Transmission/Aux Transmission Archiver Previous Forum Posts 0 April 29th, 2008 02:14 AM
Transmission/Aux Transmission Archiver Previous Forum Posts 0 October 12th, 2007 02:51 AM
Distributor, transmission, other transmission, etc. Archiver Previous Forum Posts 0 May 21st, 2004 02:27 AM
Which transmission? Archiver Previous Forum Posts 0 January 6th, 2003 01:58 AM


All times are GMT +1. The time now is 07:10 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd 891731258770|1730225460|0