The Stovebolt Site Forums The Shop Area The Electrical Bay Hooking Up An Overdrive

I need advice on how to hook up a three speed standard overdrive transmission in my 62 1/2 ton Chevy truck-235 six. I plan to run wires to a flip switch in the cab instead of using the carb and governor. I would manually switch to overdrive as needed. The rest of the time I would use the standard three forward gears if I needed to pull something like a trailer or a hill. Any ideas or suggestions? The guy I bought the trans from said the flip switch will work...Thanks in advance for any ideas.

Take a look at:

http://www.classictruckshop.com/clubs/earlyburbs/projects/over/drive.htm

specifically the picture of overdrive electrical system. Put the switch in instead of the governor. Only problem is remembering to turn off the switch when below 23 mph.

Full info also available in standard shop manual for your truck.

Should work fine.

Is there a specific reason for 23 MPH or is that just a figure of speach for, when you slow down you must disengage the overdrive?

The factory figured 23 mph because lugging the drivetrain is bad news for the freewheeling clutch rollers and cage. These pieces can't take much in the way of side loads, and they're difficult to locate if they need replacement. The planetary gearset also suffers from this stress. It's a good idea to wire an idiot light as a reminder that the solenoid is engaged, It's all too easy to forget and "bog" down.

The 'Burb page diagram is interesting but overly complex if you just want to control the solenoid. All that "split shifting" may be fun for a while, but a bother to do all the time. All you need is a toggle (and light) between the power source and solenoid.

I was always interested as to why no one has ever considered wiring a simple push-pull switch to the gearshift lever near the knob, in a similar fashion to all the big trucks on the road. The mechanism and method is different, but the results would be the same. Close proximity to the overdrive switch when and where you need it!

When I was running my overdrive setup, JC Whitney offered a shift knob with a momentary horn switch built in - a terrible idea but I was able to replace that switch with a toggle for the OD. It worked fine after adding a relay to the solenoid.

I am going with this same set-up on my 50 chevy truck. I have been told that you can actually hook 12 volts directly up to the solenoid with out hurting it. Is this true. If not, how many volts to use is the question? Thanks

Thanks to all who replied to my original question about hooking up my overdrive! I plan to install the three speed overdrive within the next two or three weeks and will hook up a light to remind me when I am in overdrive so as not to lug the transmission. Update later.