Great! You're welcome.

Drove up to Tractor Supply and picked up a 2 gallon jug for $20.  It's called "Traveller Ford Tractor All Mineral SAE90 Transmission Fluid".  I'll change it as soon as my garage thaws out.  Thanks!

"All purpose" means it can be used in diffs and manual transmissions but they mean modern manual transmissions since they don't contain brass parts. It can take quite a while for the damage to show up but if it were me I'd swap it out for mineral oil soon. My '53 shop manual calls for "mild E.P. gear oil SAE 80" That's an obsolete designation and I doubt you would find a straight 80 weight mineral oil anywhere these days. Tractor Supply carries "Ford Tractor Transmission Oil" in 85W90 I believe without going out to my freezing garage to look at my jug. That's the stuff you want, or the same from NAPA Auto Parts. I've been using it for years with no adverse effects.

I recently used Wolf's Head SAE 80W-90 Hi-Performance HDX All Purpose Gear Lube to top off my 55 Thunderbird manual transmission and R10 O/D.  Should I drain and refill it with mineral oil?  If so I see there are many types of mineral oils available.  What is recommended? 

Check the relay (located on the firewall) points. I recently had to file and adj. the tension on mine when OD wouldn't engage. Easy to do, the hardest part is bending the tabs that hold the relay cover on.
I use Ford tractor transmission oil from TSC in my gearbox.


"FREE SAMPLE"

There are at least some modern hypoid GL-5 oils which are safe on yellow metals.  Motul is one brand that manufactures such an oil.  Check with your favorite oil brand before hunting down some special type of oil.


Lawrenceville, GA

I use NAPA part # NHF65201 which is  GL-1 80/90 mineral oil , they sell it by the gallon. I believe it is the proper spec oil for the overdrives. 

If the solenoid isn't installed it will never shift into OD. I hope I read your question correctly.

You can test the one in your car by bypassing all the control circuit except the relay. Wire a toggle to the relay, push the cable in and when you're at a suitable speed turn the switch on and let off the gas. It should shift. You can also test the solenoid in the car by attaching a long jumper to the SOL terminal on the relay and touching the other end to the hot battery post. It should click. If it clicks and the OD still won't engage the solenoid may not be installed correctly so that it can engage the OD drive plate. If you can pull the solenoid plunger out of the trans without 1st turning it 1/4 turn ccw it's not installed correctly..

Good catch, no it keeps it out of freewheel when manually disengaged like it should.

I'm going to guess it has to do with they governor  wire, i didnt get a reassuring click when plugged it in so it may not be connected. I'll crawl under it friday and see if that is it, for now, i'll backroad it to work.  

On a similar note, i had a spare transmission with a block off plate on the solenoid hole, so would that work normally just without the passing kickdown?

It should only freewheel with the Overdrive lever pushed in.  With the lever pulled out, the transmission should not freewheel.

Lorena, Texas (South of Waco)