3 speed overdrive swap.


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By MattsY - 5 Years Ago
Anyone ever swap a standard 3 speed manual for a 3 speed manual with the Borg Warner overdrive? I just came into possession of a functional overdrive transmission and was wondering if the swap is as straight forward as wiring the governor, relay, kickdown and running a cable.....and if so, is it worth the effort? Your input is appreciated!
By miker - 5 Years Ago
Kind of depends on the individual transmissions. The short answer is probably yes. Vehicle type and year, casting numbers on the existing trans and new one, someone here will know. Rear mount (on a car) and driveshaft will need a look. But it’s well worth what it takes in most cases.
By Ted - 5 Years Ago
If you can make it happen, it’s definitely worth the effort.  Just be sure to start with an overdrive transmission that’s in fairly good condition.
 
Having switched a couple of cars over to an overdrive transmission from a straight three speed, some of the things to watch out for include:
Bellhousing bolt pattern
Compatible bellhousing depth
Input shaft length (cars are different from pickups)
Input shaft diameter and spline count
Transmission mount location
Overall transmission length
Output shaft diameter and number of splines
 
If all these match the current three speed transmission, then the O.D. tranny will be reasonably easy to bolt in.  But with different years on those transmissions, there are differences with some of those simply being car versus pickup applications.  Anything that’s different must be compensated for.  For me, the transmission mounts were always different thus requiring modifications to the existing transmission mounts.  Tranny input splines being different are easily compensated for with the appropriate splined clutch disk.  Because the transmissions were different in length, that required a different driveshaft as well as having the appropriate yoke on the end to match up with the O.D. output shaft.  For my last swap, the yoke for a Ford C6 automatic happened to be the same as the 1963 T-85 O.D. tranny that was retrofitted into a mid Fifties Ford car.
By MattsY - 5 Years Ago
I'll start by saying I am so glad I joined this forum. Good information from great people! I'm am certainly not new to muscle cars or drag cars, but I'm totally green to these y-blocks and this pre-muscle stuff. The transmission is from a '55 Ford sedan and I've got a '54 sedan, so hopefully there aren't too many differences. Also, I got the overdrive with the bell, so looks like that's at least one potential variable taken care of. Everything else I will be sure to go through as to avoid having that one issue that usually pops up and delays the maiden voyage. Lol!
By DryLakesRacer - 5 Years Ago
The OD cars usually had a little deeper rear gear. usually 4.11's
Unless your going to the trouble of putting it in like stock; I did one years ago by just a cable and a toggle. I liked a power take off style cable and made a mount/holder pretty close to the arm on the trans and at the dash.
NEVER EVER switch on the solenoid without the OD engaged. For the most part I left mine engaged so I didn't need to worry but it's in freewheeling and you need to get use to that too.
I was advised to never use 1st over since you could without all the stock wiring doing the connecting this simple way.
I got pretty good driving it as a 5 speed (spilling gears) just to screw with guys; had mine in a pick up.
Good Luck 
By Daniel Jessup - 5 Years Ago
take a look here when you have time, plenty of videos, pictures, and other helpful advice learned by my mistakes!

https://www.hotrodreverend.com/in-progress/tag/Borg%20Warner

subscribe to the blog if you like as well
By 57RancheroJim - 5 Years Ago
Most swaps are fairly straight forward, some times small differences in clutch spline or yoke as mentioned. Be sure you have a working solenoid those are getting like hens teeth to find. I have an f100 and my Ranchero both converted to OD with just the cable and a toggle switch.. 1961 T85 in the Ranchero and the rear mounts were right were it was suppose to be, had to use a 23 spline clutch disk.  I sometimes push the cable in so it's in freewheeling and shift gears without using the clutch just to baffle the passenger LOL
By Lord Gaga - 5 Years Ago
57RancheroJim (3/27/2019)
Most swaps are fairly straight forward, some times small differences in clutch spline or yoke as mentioned. Be sure you have a working solenoid those are getting like hens teeth to find. I have an f100 and my Ranchero both converted to OD with just the cable and a toggle switch.. 1961 T85 in the Ranchero and the rear mounts were right were it was suppose to be, had to use a 23 spline clutch disk.  I sometimes push the cable in so it's in freewheeling and shift gears without using the clutch just to baffle the passenger LOL

Have you ever shifted into 1st while the car is rolling?
By 57RancheroJim - 5 Years Ago
Lord Gaga (3/28/2019)
57RancheroJim (3/27/2019)
Most swaps are fairly straight forward, some times small differences in clutch spline or yoke as mentioned. Be sure you have a working solenoid those are getting like hens teeth to find. I have an f100 and my Ranchero both converted to OD with just the cable and a toggle switch.. 1961 T85 in the Ranchero and the rear mounts were right were it was suppose to be, had to use a 23 spline clutch disk.  I sometimes push the cable in so it's in freewheeling and shift gears without using the clutch just to baffle the passenger LOL

Have you ever shifted into 1st while the car is rolling?
I've heard that can be done but I have never tried it, call me chicken LOL