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


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

Reply
 
Thread Tools
  #1  
Old April 24th, 2014, 07:26 PM
FetchMeAPepsi's Avatar
FetchMeAPepsi FetchMeAPepsi is offline
-= Dues Paid =-
 
Join Date: Jan 2013
Location: Edmond, Ks
Truck: 1962 4x4 GMC CECILIA
Posts: 1,724
Rep Power: 545
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 light
Default Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

Sharing all the info I have on the Muncie SM318 trannys. Rebuild kits are easy to find on Ebay or you can buy the pieces part by part at your local store and make your own gaskets. See me rebuild mine starting here. Hijinks included.


The OD on some of these 318s is supposedly a big difference in performance for our trucks, allowing them to get up to 68mph at top end and get much better gas mileage. I might be falling into one here shortly. You have to have a special drive shaft made or have yours shortened to make it work, but then you're good to go.
They work by kinda putting a second transmission behind your first one. The second tranny is run by an electric solenoid that pushes it into gear when you want to up-shift. You get up to 50 or so with your normal tranny, hit a button, and it shifts into "fourth" gear and you can continue on.

Since its two different trannys you actually have six gears now, but mainly theyre used for a 4th gear. Here's a wiring diagram I found for the OD unit







You can buy a repo solenoid here:
http://www.fifthaveinternetgarage.co...counter_3.html



Attached is scans of the SM318 rebuild manual, OD operator's manual, OD service manual, OD rebuild manual,OD wiring document, and OD tips and tricks.
Attached Files
File Type: pdf mc318.pdf (586.2 KB, Multiple views, 107 clicks)
File Type: pdf bwoperators[1].pdf (7.99 MB, Multiple views, 55 clicks)
File Type: pdf bwservice[1].pdf (5.84 MB, Multiple views, 39 clicks)
File Type: pdf bwrebuild[1].pdf (947.2 KB, Multiple views, 41 clicks)
File Type: pdf bwwiring[1].pdf (335.4 KB, Multiple views, 26 clicks)
File Type: pdf bwtips[1].pdf (803.7 KB, Multiple views, 38 clicks)
__________________
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
  #2  
Old July 16th, 2020, 04:32 AM
Tony Tony is offline
Junior Member
 
Join Date: Jul 2020
Location: NORTH PLATTE, NE
Truck: 1960 GMC
Age: 55
Posts: 1
Rep Power: 0
Tony is on a distinguished road
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

Info like this when you need it is invaluable!
Reply With Quote
  #3  
Old July 16th, 2020, 08:09 PM
Quigley's Avatar
Quigley Quigley is offline
Senior Member
 
Join Date: Mar 2013
Location: New Hampton,Iowa
Truck: 1966 1000 Wideside 1962 1500 Wideside 401 Magnum
Posts: 187
Rep Power: 131
Quigley will become famous soon enoughQuigley will become famous soon enough
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

The overdrive version is a SM319. It uses a Borg Warner R10 overdrive unit. The ones I have used are the same length as th 318 and will bolt right in with no modification to the driveshaft. I used the side plate with the original shifting arms off the 318 and kept my column shifter without any mods. Dave
Reply With Quote
  #4  
Old July 17th, 2020, 01:42 AM
LEWISMATKIN's Avatar
LEWISMATKIN LEWISMATKIN is offline
-= Site Supporter =-
 
Join Date: Jan 2013
Location: RIDGE MANOR, FLORIDA
Truck: 1965 1002 GMC V6-305E
Age: 64
Posts: 307
Rep Power: 173
LEWISMATKIN will become famous soon enoughLEWISMATKIN will become famous soon enoughLEWISMATKIN will become famous soon enough
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

the sm319 is the long mainshaft version. the sm 318 has a shorter mainshaft.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #5  
Old November 24th, 2020, 03:37 AM
Shsh Shsh is offline
Junior Member
 
Join Date: Jan 2020
Location: Foley, AL
Truck: 1968 truck
Age: 37
Posts: 2
Rep Power: 0
Shsh is on a distinguished road
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

Quote:
Originally Posted by Quigley View Post
The overdrive version is a SM319. It uses a Borg Warner R10 overdrive unit. The ones I have used are the same length as th 318 and will bolt right in with no modification to the driveshaft. I used the side plate with the original shifting arms off the 318 and kept my column shifter without any mods. Dave
Is this synchronized?
Reply With Quote
  #6  
Old November 26th, 2020, 11:41 PM
Quigley's Avatar
Quigley Quigley is offline
Senior Member
 
Join Date: Mar 2013
Location: New Hampton,Iowa
Truck: 1966 1000 Wideside 1962 1500 Wideside 401 Magnum
Posts: 187
Rep Power: 131
Quigley will become famous soon enoughQuigley will become famous soon enough
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

Quote:
Originally Posted by Shsh View Post
Is this synchronized?
No it’s not.
Reply With Quote
  #7  
Old October 30th, 2021, 01:21 AM
Truckee Truckee is offline
Junior Member
 
Join Date: Oct 2021
Location: Chatham, Virginia
Truck: 1965 1000
Posts: 1
Rep Power: 0
Truckee is on a distinguished road
Smile Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

I’m about to install a SM318 in my 1965 1000 series truck. There’s no bell housing dust cover on the truck. Is it necessary to have one and, if so, where in the world can I find one? Thanks, Tim
Reply With Quote
  #8  
Old October 30th, 2021, 10:16 PM
FetchMeAPepsi's Avatar
FetchMeAPepsi FetchMeAPepsi is offline
-= Dues Paid =-
 
Join Date: Jan 2013
Location: Edmond, Ks
Truck: 1962 4x4 GMC CECILIA
Posts: 1,724
Rep Power: 545
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 light
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

Quote:
Originally Posted by Truckee View Post
I’m about to install a SM318 in my 1965 1000 series truck. There’s no bell housing dust cover on the truck. Is it necessary to have one and, if so, where in the world can I find one? Thanks, Tim
It's not 100% necessary, but it is nice to have. Thing is, they're like frog teeth. Lots of shops took 'em off and tossed 'em when they worked on the clutch out of laziness. Lots were shorn off when people hit bumps driving in the bush. And a bunch were probably just rusted out. They take a lot of damage.
If you can find one, grab it with both hands. If not, just slide your sm318 up in there and drive on, brother! Just glance up there from time to time and make sure the neighbor's cat isn't up there!
__________________
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
  #9  
Old November 2nd, 2021, 05:02 AM
AZKen's Avatar
AZKen AZKen is offline
Senior Member
 
Join Date: Jul 2014
Location: AZ
Truck: 6066GMC
Posts: 1,605
Rep Power: 513
AZKen is just really niceAZKen is just really niceAZKen is just really niceAZKen is just really niceAZKen is just really niceAZKen is just really nice
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

Quote:
Originally Posted by Quigley View Post
No it’s not.
How do you shift it if it's not synchromeshed in 2nd and 3rd???? Are you saying it's a crash box? NOVAK says "SM" stands for Synchromesh.
My understanding is the 319 is basically the same as the 318 with OD adapted? It's not fully synchro.

Last edited by AZKen; November 2nd, 2021 at 05:29 AM.
Reply With Quote
  #10  
Old November 3rd, 2021, 02:37 AM
LEWISMATKIN's Avatar
LEWISMATKIN LEWISMATKIN is offline
-= Site Supporter =-
 
Join Date: Jan 2013
Location: RIDGE MANOR, FLORIDA
Truck: 1965 1002 GMC V6-305E
Age: 64
Posts: 307
Rep Power: 173
LEWISMATKIN will become famous soon enoughLEWISMATKIN will become famous soon enoughLEWISMATKIN will become famous soon enough
Default Re: Muncie SM 318 (sm318) 3 speed Transmissions All Documentation I could find

The sm-318 & sm-319 are the same transmission except for the length of the mainshaft(tailshaft). Neither are syncronized in 1st gear. both are syncronized in 2nd & 3rd. the internals are the same.
__________________

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

Bookmarks

Thread Tools

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
Re: [6066 GMC] SM 318 Three speed Archiver Previous Forum Posts 0 July 28th, 2008 01:21 AM
SM 318 Three speed Archiver Previous Forum Posts 0 July 22nd, 2008 01:40 AM
Re: [6066 GMC] Upgrading from SM-318 3-speed to SM-420 4-speed in 65 GMC 1002 Archiver Previous Forum Posts 0 September 25th, 2007 04:05 AM
Re: [6066 GMC] Upgrading from SM-318 3-speed to SM-420 4-speed in 65 GMC 1002 Archiver Previous Forum Posts 0 September 24th, 2007 12:24 PM
Upgrading from SM-318 3-speed to SM-420 4-speed in 65 GMC 1002 Archiver Previous Forum Posts 0 September 24th, 2007 06:05 AM


All times are GMT +1. The time now is 09:27 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd 681711554703|1710448024|0