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

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  #1  
Old August 30th, 2018, 03:42 PM
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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
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Old September 1st, 2018, 11:07 PM
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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
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Old September 1st, 2018, 11:10 PM
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Default Re: Overdrive 3 Speed

Dave:
Here is location of manuals.
Regards
Steve

http://devestechnet.com/Home/HowTo
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Old September 6th, 2018, 01:52 AM
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Default Re: Overdrive 3 Speed

Steve, Thank You for the info! Think I will go ahead and put in the overdrive. Dave
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