I have found a 3 speed overdrive transmission at a good deal. It came out of a 1969 F-100 with a 390 in it. The salvage yard does not know how the transmission drove. He told me everything seems to move freely. What should I look for when buying a used overdrive transmission? He does not have the original bell housing. Will the bell housing work that is in my 66 F-100 with a 390 and a Long Wheel Base regular 3-speed transmission? He has another Ford Overdrive Transmission but he says it is smaller. Thanks for all your help.

 

The heavy duty truck OD will have a U-joint coupler on the output shaft. The light duty car and truck OD will have a slip joint coupler, just like an automatic transmission.
Look for the T-85N casting on the passenger side of the case to make sure you have the heavy duty one. These are nearly bullet proof, as long as they haven't been really romped on like at the race track. They cannot handle that kind of torque.

Without the electricals working, it is hard to tell if the OD is OK or not. You can check the transmission itself the usual way.

The transmission should have a solenoid on the driver's side, and the governor on the passenger side at the rear.

If you can find the truck it came out of, get the wiring harness for the OD, the relay on the firewall, the lockout cable and handle, and the kickdown switch under the accelerator. It won't make any difference if it is out of a 6 or 8 cylinder except for the bellhousing.

If you can also get it, get the driveshafts and carrier bearing. Otherwise, you'll need to have those fabricated. They are different for the short and long bed as well.

Hope this helps!

 

Banjopicker66,

Thanks for your help. The 69 truck the overdrive came out of is no more. I have some of those items you mentioned, because my 66 originally came with an overdrive transmission. I hope I still have all of the electrical parts. So can I use my bell housing off my LWB 3 speed regular transmission? I think I got the original drive shaft. That is why they used to LWB transmission in my SWB truck. Do you have a picture of what the overdrive transmission is supposed to look like? What does the governor look like? Do you have to come to a complete stop before you can put your overdrive in low gear? What would you do to a used overdrive transmission before you put it in to your truck? Again thanks.

 

Good questions, I'll try to answer. First, send me an e-mail address that can receive pictures; I've got some of my old OD before I sold it.
You SHOULD be able to use the same bellhousing. I think.
As for prep work, I would drain it and refill it, that's all.
And yes, 1st gear is not synchronized, so you have to come to a full stop to put it in gear.

 

The bellhousing will be the same for sure. I am new to the overdrive thing myself. I will be posting as I have just installed mine and will be sorting out how and if the thing works. Wish me luck!

 

banjopicker66 was verry helpful to me. Becouse of him I have a C6 sitting in storage, The overdrive is just to much fun. 65mph at 2000 Rpm. If you dont have the firewall relay or kickdown switch, you can use 3 power trim relays out of a 94-02 Johnson 200-225 outboard, These are small 45 amp relays that draw almost no current, They have good contacts and are sealed units I used 2 to replace the kickdown switch and have a switch on the wheel, but it could be
located on the dash , or on a braket on the throttle pedal ( any momentary Normaly open switch would work ) I did have to pull the main solinoid and clean it up, I replaced the wires and sealed it up good befor I put it back in. It works like a charm.