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 August 30th, 2018, 04:42 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
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 135
Quigley will become famous soon enoughQuigley will become famous soon enough
Default Overdrive 3 Speed

My 62 3/4 ton truck has .456 rear gears and I would like to slow the motor down some at highway speeds. It has a 3 speed (SM318)transmission , I have access to a SM319 transmission with overdrive and was wondering if anyone has done a similar swap and if it was worth it. I AM going to keep my column shifter and am not interested in floor shift conversions. Thanks for any input. Dave
Reply With Quote
  #2  
Old September 2nd, 2018, 12:07 AM
sclor's Avatar
sclor sclor is offline
Senior Member
 
Join Date: Jan 2013
Location: New Orleans, LA
Truck: 1966 GMC 1000 series fenderside
Posts: 203
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 131
sclor is on a distinguished road
Default Re: Overdrive 3 Speed

Dave:
I have the seven bolt side cover 3 speed with overdrive transmission. My tranny has synchronized first gear. I am running 3.54 rear end. Results in about 2000 rpm's at 60mph. I think it was one of the best upgrades I made. Parts are getting a bit hard to source, but so far I haven't needed anything since I installed it a few years ago. Hardest parts are electric solenoid and governor switch. My vote would be to go for it. I think it would cut your rpm's about 30% in overdrive.

Hope this helps. Manuals for tranny can be found online for free. Let me know if you are interested.
Regards
Steve
New Orleans
Reply With Quote
  #3  
Old September 2nd, 2018, 12:10 AM
sclor's Avatar
sclor sclor is offline
Senior Member
 
Join Date: Jan 2013
Location: New Orleans, LA
Truck: 1966 GMC 1000 series fenderside
Posts: 203
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 131
sclor is on a distinguished road
Default Re: Overdrive 3 Speed

Dave:
Here is location of manuals.
Regards
Steve

http://devestechnet.com/Home/HowTo
Reply With Quote
  #4  
Old September 6th, 2018, 02:52 AM
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
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 135
Quigley will become famous soon enoughQuigley will become famous soon enough
Default Re: Overdrive 3 Speed

Steve, Thank You for the info! Think I will go ahead and put in the overdrive. Dave
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
Saginaw 3 speed overdrive frost66gmc 1960-1966 GMC Marketplace 0 August 6th, 2015 02:11 PM
3 speed saginaw with overdrive frost66gmc 1960-1966 GMC Marketplace 1 February 26th, 2015 11:16 PM
3 speed with overdrive transmission Archiver Previous Forum Posts 0 February 26th, 2009 01:04 AM
RE: THREE SPEED NEEDS OVERDRIVE Archiver Previous Forum Posts 0 December 14th, 2007 01:14 AM
3-speed overdrive Archiver Previous Forum Posts 0 August 17th, 2006 02:21 AM


All times are GMT +1. The time now is 03:37 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd 911731456399|1730385460|0