It started doing this about a year ago, and will come and go. The longest it's stayed "lit up" and in third gear is about 25 miles and it goes normal. Often it's just for a minute, or ten.

I had the wire from the shifter though the floor break about 9 years ago, and that's put back nicely. It's not acting like it did then with the shuddering, etc. I'll just start it up and sometimes the light is on and it won't go into fourth till it decides to for it's own reasons. Do these overdrives do this a lot when they get older?

I tow a trailer fairly often, so disabling this entirely is not an option in my case. An emergency disable I'd be interested in hearing about, if , say, I'm on a road trip or something. I'd like to just get it to stop it, of course, if I'm told what to look at.

Thanks,
Steve