3 Speed Overdrive

[john sanford]

I have a 1955 F-100 with a std 3 speed transmission. I want to add overdrive to this truck. Can anyone tell me what year range that may fit?
Cars and trucks? I was told that the flat heads used the same trans, but I don't that for sure.
Any help is appreciated.

 

[Mac VP]

Because the trucks used the longer trans input shaft (and deeper bell housing) from 1953 on, you can't use any version of the car trans in your truck. Also, there is no way to simply add-on a Borg Warner overdrive section to your existing Ford standard 3 speed trans.

You'll have to find one of the original Ford pickup truck complete overdrive transmissions from 1953 to 62. We have the rebuild parts for them, and have rebuilt them in our shop. However, finding a good core is your biggest hurdle. Be careful when checking ads for these. The clue is the larger (1-3/8") diameter input shaft. The pickup overdrive trans always had the 9 bolt side loading cover.

 

[40cpe]

Is the input shaft length the only thing prohibiting installing a car trans in a truck? Can the input shafts be exchanged?

 

[john sanford]

From what I gather, cars also were fine spline input shaft and I've heard you can just swap discs.
Not sure if this is true or not.

 

[42merc]

I believe Van Pelt said the car input shaft was too short.

 

[Beav]

A number of people have overcome the length issue by either swapping input shafts, when possible, or having a machine shop make an extended pilot bearing. Search the threads at ford-trucks.com

 

[hardlyrider]

They pop up on eBay occasionally, though not the best place to source one. I've done the conversion in a '58 and a '72 (though discontinued as a factory option after '71). I love them and think they're worth the trouble. A truck model is the easiest way about it and there are probably more available than car models.

 

[down-the-road]

Has anyone tried going the other direction - putting a truck OD trans into a car?

I located a truck OD trans and it looks like the plate holding the input shaft bearing is a larger diameter than what is on my original 3 speed car trans. It won't go into the car bell housing without some modification. Also, this is from a mid-60's truck, not a 53 to 62 as mentioned by Mac VP. Picture of truck trans (blue paint) shows extra set of holes for mounting to bell housing. If I remember, the input shaft diameter is larger for the truck than the car trans. Overall length of trans housings are different. Thanks

 

[TedEaton]

Trucks and cars had different depths on the bellhousings. As a result, the truck input shafts are typically longer than the car input shafts so this must be compensated for. Assuming you can get around any differences in the transmission bolt pattern, then some kind of spacer could be fabbed to make up the difference. The overdrive trannys I have here for the Sixties Ford pickups are also considerably shorter in overall length which would require some driveshafts longer than normal for the cars.

 

[down-the-road]

Thanks for the additional information. One set of four mounting holes does match between the truck transmission and the car bell housing. Other than the difference in length, there is also a difference in connection to the output end of the transmissions. The truck trans has a yoke directly attached on the output end. The car trans has a splined output shaft. This would require some driveshaft modifications.