Saginaw 3 speed overdrive Gurus needed

Mine was off a Saginaw. Some others are different.

There is a 1 1/2" dia. soft plug on the top of the tail shaft housing.
I took a chisel and drove a slot in the center of the plug. Small pry bar and it popped right out. Snap ring is right there. Stand the housing on the front surface expand the snap ring and the whole tail shaft falls out.

Stay in the center of the plug with the chisel. You'll set the see why when you get the plug out.

Thanx to Squirrel for the plug confirmation.

 

My first car had the OD trans in it. My dad loved them, as they were hot back in the 40s and 50s. This is also what I am putting in my 37. As far as I am concerned you can't beat them. They came with either 4:56 or 4:11 rear ratios. Do not try to use them with anything higher. The basic formula is to take your ratio and multiply it by .7 and this is your final ratio. 4:11=2:87 & 4:56=3:19 a 3:73=2:61 which is tough to tote. My set up with the 4:56 will give me 60 mph at about 2200 rpm. They are quick off the line (they just do not shift real fast). The governor is a centrifugal weight switch, hit 25 to 30 mph and the contacts close grounding the overdrive relay, let up on the throttle to float the drive line and the solenoid will engage. It does this by inserting a pawl into the planetary ring thus changing the final output ratio. Engaging and disengaging the pawl under power can snap it off. Like putting an automatic into park before you stop.
There is a kick down switch under the accelerator pedal that when you push it to the floor will kill power to the ignition system momentarily breaking the power on the drive line so the pawl can be pulled out and you are back to 4:11 or 4:56. Once you have reached speed (or blew someone's doors off) float the drive line and it goes right back into OD.
My Merc would in 1st OD (above 30) hit 70 mph, second was around 90 mph, 3rd was what your nerve would allow.
Chevy's would only hit around 60 in 1st but in 2nd they came close to 100. I think this was due to the internal gearing between the Ford and Chevy trans. The best were the Studes. Man they would fly, never got to drive one only know I got my doors blown off by a couple.
The ODs will only hold a car while in Reverse or with the cable pulled and the OD locked out. These trans will manually lock out the OD when you put it in reverse or you would not be able to back up because it has a one way bearing (similar to an automatic) this allows freewheeling below the engagement point. I kept the Merc in 2nd took off in 2nd and would roll up to near 30 then free wheel to the next stop sign.
Another thing they are fantastic on gas mileage. I could get 22 to 23 mpg with the Merc with no problems. That was nice since I was only making $1.00 per hour.
They are great but you need to be careful because you can get into trouble if you do not completely understand how the thing works. In short you can tear them up. I knew a lot of guys who never used the OD because they did not like the freewheeling aspect or the engagement process so they just kept the cable pulled and drove with it locked out. Or they had broke the pawl trying to push the cable back in while driving. If you have one and use it right you will find out they really are the best of both worlds.

 

I had a 59 O.D. transmission in my 55 back in the day. That was a fun experiment and I learned a lot about the system.

This time, I'm doing the Saginaw 4 speed w/ Borg-Warner R 10 O.D. conversion.
Almost finished it this afternoon.

Did you know that you can put the 1st/2d slider in backwards? Everything works fine until you try to put the side cover on. I didn't!

I'm getting much faster dis***embling and re***embling Saginaw 4 speeds

Tomorrow for sure!

 

in 1961 i bought a ford starliner w/390ci 375hp,w/3spd od, we did a lot of top end racing, and when crusing about 70mph in od if someone puled up to race i just quickly turned the ign key off then on and it would shift out of od without having to floor the accelerator, after about 120mph let off the petal and it would shift into od, then hold on. i am building a 34 roadster now w/331 cad eng w/t-85 ford od,9"" 4.11 rear, i have a flathead rdstr. pu w/4.44 gears w/columbia od [tall tires & linc.gears. out of linc. gears so for a 27 t i'm colecting parts for i have columbia w/4.11 grs and stock 48 trany and tall tires. also have 2 model A's w/borgwarner od's. ****** gear ratio, rear ratio and tire size''height'' are important w/od. also camshaft.

 

Another question about this conversion. Got mine all together and found that you can't get all the way into 1st gear with the overdrive engaged. The rod that is supposed to push the overdrive out when you go into reverse is hitting the 1-2 fork arm. This makes perfect sense as in the 3 speed O.D. that arm is what pushes the rod (reverse in the 3 speed is where 1st is in the 4 speed).

Looks to me that the rod needs to be shortened at least 1/8" to clear. Then shorten it even more to allow the fabricated tab to be welded on the 4 speed reverse arm to clear. I'm guessing it will actually be shortened about 1/2" to allow clearance with a 1/4" tab.

I have read all I can find on the net about this swap and no one has mentioned having to shorten the rod. I don't mind doing it, but just wondering if I am missing something.

 

Btt

 

Please?

 

manual

http://selectric.org/manuals/muncie/67overdrive.pdf

 

Thanx, Jim.

I guess I am going to shorten the 'Plunger' and weld a tab to the reverse Shilfter Shaft ***embly.
Tack and check, tack and check, tack and check................................

 

Zombie thread alert.
asking about this plunger

number 6.
Only piece I need to finish a full sync OD
Any info on number or source?

 

I think the GM part number is 3886325 but that probably won't help much. Was used from 66-mid 70s?

 

I have one, but it seems like it is all one piece. Maybe from an earlier transmission. Would it work?

 

Set it up with a lock up mechanism from a Muncie.
The Muncie lock out will not work with the Saginaw case. But the parts from the adapter back are the same.
Set it up this way to try to see how far it moved.
Emgaged

disengaged

the Saginaw lock out in its case
Engaged

disengaged

probably will have to reverse engineer a reverse lockout.

dang it

 

That’s the Muncie one
The Saginaw is different

always something
Need one part each for both my setups to work.

 

A length measurement would be cool.
It only has to travel 5/16- 3/8
Could test with a wooden dowel.
Educated guess for adding length due to the spring pressure on the lockout

hmmmm

 

Go for it!

 

Scale it out via a percentage from dimension at right of diagram.

 

Hmmmmmm
If any folks wondered what the solenoid does, here it is
The solenoid in

solinoid out

The cable operates this guy in and out of the planetaries

 

The part number I gave might be in the GM Standard Parts Catalog, which might give dimensions.

I was trying to look it up, but gmpartswiki isn't loading

 

well, that's no help

 

While they’re mostly Ford guys, Mac at Van Pelt Sales knows as much about the B/W o/d’s as anyone. Might be worth a call to him.

 

The part he's looking for was used on the Saginaw transmission's overdrive. Starting in 1966. Does Mac do anything that modern? or off-brand?

 

I don’t know. But if it’s a BW unit, he’s probably seen more than just the Ford uses. If he just had a line on a drawing with dimensions that would help. If it’s not a BW, then I made a bad ***umption.

 

I think I’ll ***emble the case and OD adapter.
Use wooden dowels to dial in the length.
Get close and put the OD housing on.
When shifted into reverse with the OD engaged, it should disengage the OD and allow use of reverse.
When parked with the OD engaged, reverse was the only gear that doesn’t free wheel if the lock out is hooked up correctly.
I think.

then machine a pin that installes from the OD side into the trans case

 

that should do the trick

I think they call that reverse engineering?

 

Bench grinder.
Grade 8. 3/8 bolt.

neutral
Reverse
Tested in an empty case with side cover and tail shaft.
Only the pin and selector installed. Definitely moves the selector
Needs fine tuning.
Will do that during ***embly
Thinks it’s a tad long.
When going into reverse with the OD engaged, the detent for reverse won’t stay.
(Simulating OD cable engaged, soliniod disengaged)
The springs on the selector shaft will move it.
But that’s an empty case. No gears or shafts.
That’s why I think I will dial it in when it’s together.

 

Reminds me of the TV series The Six Million Dollar Man. He once ground a set of aircraft piston’s on a bench grinder. Naturally he dialed the piston’s in with his bionic eye.

 

Solinoid out, we have reverse detent

silinoid in, reverse locked out