Transmission / Overdrive: Overdrive relay vs. solenoid

[Dwc1298]

On a 48 Champion, is there a way to tell which part is bad (or going bad..hopefully not both)
The overdrive works great just starting out for the day, but after a day of, say running errand, and driving say 60 miles, it won't kick into overdrive. It's almost like maybe one of them stops working due to overheating?

[StudeRich]

There is a really good troubleshooting "Tree" guide to Overdrive problems in the Studebaker Shop Manual and the Borg Warner Overdrive Manual. If your Overdrive ever consistently quits.

When the books were written they were not Old enough for this to happen, so not sure if it is mentioned. No one expected them to Last 72 Years!

However in your case the Solenoid is likely getting it's Points wet with Oil and needs cleaning and New seals to keep it out.

[Commander Eddie]

It may be as simple as a loose wire/bad connection. Crawl under the car and closely examine the wire connections and wires. Over time these connections can become loose from vibration or constant heating and cooling. The tiny wires can become brittle. Excess dirt or corrosion on a connector can increase resistance or block the flow of electricity. Tidying things up may save you some money and time. The overdrive components themselves are pretty robust and generally give many years of trouble free operation.

[RadioRoy]

Usually the biggest culprit is the governor, which is mounted towards the rear of the transmission. They fill up with oil. It's easy to remove with a pipe wrench and you can take the cover off on your work bench.

<edit> Rich just questioned me about the unit having seals. There are none called out in the parts catalog, and I just don't remember if they have seals or not. The ones in my parts stash do not have external seals. <edit>

But the best thing to do is troubleshoot and determine the actual source of the problem before taking things apart.

[Ross]

Of course the first thing to do is look to have tight clean connections throughout. With the symptom you describe I'd look at the relay. When it is cold, turn the ignition on and ground one of the two lower wires on the kickdown switch. You will hear the solenoid make a nice click and pull in. Try that again when the car is hot and you will likely get nothing though you may hear the relay itself click. What I have found many times is that the relay's internal connections are corroding and it can no longer pass the big pull-in current when it is hot. Remove it and pry the cover off and you will see that various contact pieces are held together by brass rivets. Sometimes these have corroded under their heads and no longer conduct--sometimes their little heads have popped off. You can carefully replace them with tiny brass screws and nuts, or as I did on my Packard 21 years ago and my Nash last week-- solder the rivets to their respective contacts. Brought those 70 year old electrical devices back to reliability at no expense.