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1955 Ford Part 79: Sorting out Overdrive and Conquering the Interstate

Updated: Aug 17, 2020

Sorting out Overdrive and Conquering the Interstate


"What? Did he pull that transmission AGAIN?" The photo below may lead you to say that, but this time let me give you a definitive, "No!"

Since I got the car back on the road there were a few things I wanted to have sorted before taking my life in my own hands and merging with I-275 traffic here in the Cincinnati area, home of the opioid epidemic! First would be the carburetor and fuel delivery situation, second would be the alignment of the front tires, and third would be a correctly operating transmission. For you faithful readers of this blog, you have seen the failures and successes of the carburetor issues and all of the fun we have had with the transmission. (One of these days I expect to be an expert on these Borg Warner overdrives!) For the front end alignment, it has been an exercise in futility. One local tire shop that aligns my modern cars said that they could take care of it, no problem. All I had to do was to bring my specs for camber, caster, and toe. When I drove to the shop to let them see it and set up an appointment, I raised the hood for the manager. He shied away and said, "I'm sorry, but we are not allowed to align any cars that have shims."

The next shop I spoke with... $124 a tire. No, that is not an exaggeration, $124 a tire. I said, "No thanks," and tabled the work for a while. I will have to check with a few more shops and see what I can find.

2 out of 3 ain't bad though - time to take it out on the interstate!

The first run took place on May 21st. Here is the video. Thankfully, I had my wife in the car with me for moral support. Listen to how she changed her tune from the beginning of the video to the end!

We only went two miles, from exit 52 to exit 54, but I could not tell if we were running out of fuel, the kickdown switch was not working right, etc. At least the car started back up just fine when got to the end of the exit ramp. Looking back, I really believe that there were two issues at play at the same time. We were not getting enough fuel - this was exaggerated by the overdrive not kicking in like it was designed. 3rd gear with 3.78's and 65 mph is pretty crazy stuff. I would imagine we were at 3500 rpm most of the time.

A couple of weeks later I installed the Holley 4 barrel (see post 78), made a few test runs with temporary plumbing, and was very happy with the results. In my opinion, fuel delivery, response, and especially idle were all noticeably better than the Edelbrock. While I still had ethanol issues and heat soak (even with a 1" phenolic spacer), things were no where near as bad as before.

Next was to examine the overdrive. I read up a little bit and specifically took note of some things over at a website called Randy Rundle is highly respected and knows his stuff. The site also has an online store that sells Borg Warner overdrive parts such as relays and solenoids. One item I read was that if your transmission free wheels in 2nd or 3rd, your vehicle most probably has a wiring problem that needs to be addressed.

I put the car up on jackstands and went to work. First up was to turn the ignition on. Next was to crawl under the car and manually ground the wire that goes from the governor on the tail shaft to the relay. (If you will recall I had purposely put a modern relay on the inside of the driver's side air deflector.) Test one - pass. There was juice to the relay. Each time I grounded the lead the relay clicked. But, there was supposed to be another almost simultaneous click from the solenoid on the side of the transmission. It was dead.

pictured above is the 12 volt solenoid that engages the pawl for the overdrive

With the ignition on and the lead to the governor grounded I then started testing the kickdown switch terminals with my test light. Yep, the juice was getting to the kickdown switch like normal - so no issues there. And, the main lead to the solenoid also had juice, but I could not figure what the problem was. I studied for a moment or two and then asked myself, "Do I have those wires on the solenoid crossed?" (The solenoid has two wires - one that operates the plunger and the other that holds it in under power to the pawl when its lead is grounded.) I switched the two wires and grounded the lead to the relay again. Two almost simultaneous clicks were heard as the relay up front sent full juice to the solenoid and it HELD!

With the carburetor freshly installed and barely out of the box, we had now also discovered what I believed to be the issue with the transmission. Time for a test drive! For some reason, my dear wife declined. However, my father-in-law, one who has been very supportive in this journey to put the car back on the road, spoke up and said he would love to take a ride. Below is some footage of the road test from his apartment to the interstate. All I can say is, what a difference. The overdrive engages like it was designed. With the dash cable pushed in I take off in 1st gear and with 3.78, there is plenty of grunt down low. Once I get up to second, we are beginning to reach 28 mph (the speed at which the governor's contacts ground the lead for the relay), but the overdrive does not engage until I let off the gas. A good shift to 2nd overdrive takes place when I back off, and once I press the gas pedal it seems like we have shifted to 3rd, but we have not quite yet. I shift into 3rd and stomp the gas, the car takes off with great acceleration and does not get into 3rd overdrive until I back off the gas pedal once again. By that time on the interstate we are in high gear and motoring along at 70 mph, a little less than 2000 rpm with plenty of room left to go faster.

What a ride!

Once we got back to the apartment, my courageous wife got up enough nerve to ask to drive the car. I said, "Sure thing, babe," and off we went... at 15-20 mph! My son and I had a little bit of fun with her during the short trip in a residential section, but all things considered, she did fine. My wife can drive the car any time she wants - I can't ask for a better woman than the one the Lord gave me. She has been so supportive all these years, and especially over the last few as we put the car back together.

Here she is in action with my son and I giving her a hard time. We ought to be thankful she puts up with us!

the Hot Rod Reverend

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