Columbia shifting on 46 ford
 

I have about 1000mi on car since rebuild. Everything works fine BUT this car has shifted into overdrive at about 55-60 mph WITHOUT me shifting it. It has difficulty coming out of overdrive mode until Ive driven in town several blocks using clutch to stop or downshift. Using overdrive switch works fine when I want to shift.
Is this a linkage problem. Driving several miles at 55-60 mph and not engaging the overdrive switch or clutch has me contused to what to look for.
This has only happened 3 times since Ive had it on the road. Want to fix quickly before it turns into bigger problem
Any advice appreciated,Thank you

Re: Columbia shifting on 46 ford
 

You need a rebuild kit for the vacuum valve . It has rubber washers and everything to rebuild the valve. Contact Two Speed Columbia parts in Arizona.

Re: Columbia shifting on 46 ford
 

Thanks! Had this problem before?

Re: Columbia shifting on 46 ford
 

Are all of the pieces to the Columbia shifting attached to your car? The Columbia should not shift unless the clutch is depressed.

Re: Columbia shifting on 46 ford
 

I would not drive the car in that condition. Having it shift without the clutch in could damage the Columbia.
You could disconnect the vacuum line and plug it to prevent any unwanted shifting.

Re: Columbia shifting on 46 ford
 

This was a handy bit of info that I was not aware of, I'll have to check into having my vacuum valve rebuilt before it causes trouble. The shift selector valve in my car was 'NOS' in 1963, a friend of mine found it in a Mercury garage parts room along with a NOS vacuum can, that he worked at in Vegas.

Re: Columbia shifting on 46 ford
 

Or better yet, send the vacuun control valve to John at Columbia Two Speed to check out and rebuild if necessary, very fair and quality work.