Transmission / Overdrive: overdrive works, but not on hot days

[SuperHawk]

Re: '64 Daytona V8 with factory T86 stick & overdrive

Lately its been getting hotter in Nevada. I drive the Daytona its first 15 minutes or so, and OD works fine. After the car gets thoroughly warmed up, combined with 85 degrees and up outside, the OD stops working. I still drive, but now I'm taching 3000 rpm at a little over 60 mph instead of my usual 2100. And when I take my foot off the gas, even at speed, I've got no engine compression. The rpms just go down to idle speed.

So, I wonder if this problem is a classic symptom of anything in particular. Maybe when a governor gets hot enough it may routinely do this ???

I'm sure I am not the only one out there who has experienced this. Any ideas?

Thanks,
Larry

[Tom Bredehoft]

Not the governor, it allows into overdrive does not keep it in. I can't think why heat would 'stick' in it OD.

[JoeHall]

I believe it is in the OD electrics, and the governor is most suspect, in not maintaining ground. Anytime ground is broken, it kicks out, as you describe. Also, could be the solenoid losing its electrical strength as it warms up, and then unable to stay kicked in all the way. Maybe the connections on the kickdown switch. Could also be the wiring and/or connections.

I'd start by making sure the transmission is topped up with oil, including the OD compartment.

[Studebakercenteroforegon]

1964 was the first year to use the 2 terminal governor, where the hot lead was channeled through the governor rather than the ground circuit.
You could take the cover off the governor and clean the contacts.

[Ross]

This is a fairly common problem caused by excess electrical resistance. Agree with cleaning the points in the governor, but would add cleaning the fuse holder on the kickdown switch. My own preference when I get an OD car is to take the KD switch apart and clean the contacts as they have to carry a momentary high current to get the solenoid to pull in.

[SuperHawk]

Per the suggestions received, here's what I did:

a) Took off governor cover and cleaned the already clean looking contacts

b) sanded patina off fuse holder

c) drove the car for a few days, and it still would not go into OD when hot

d) took kickdown switch apart, sanded contacts. Discovered a bit of looseness in one of the top terminals, so I put the top of the kickdown switch ( bakalite type material ) onto a heavy and flat steel surface and re-peened the rivet holding down the suspect loose terminal. That tightened the looseness, and I reassembled and reinstalled the kickdown switch and now overdrive works as it should even in the 100 degree weather.

Problem solved. Thank you to all who responded !!

Larry