F1 Front drive shaft yoke

B_man_Al

B_man_Al

Senior Member
Does anyone have a picture of an F1 driveshaft inserted into a 3 speed transmission?

I had a drive shaft made for my F1, and the machined portion of the front yoke spline sticks out from the end of the transmission by about 2 1/2 in with the differential connected.

The total length of the splined portion is about 3 1/2 in. They left a 1" slip allowance.

When fully bottomed, the yoke sticks out about 1 1/2 in. The output shaft on the transmission extends about 1 " beyond the end of the transmission, so the total engagement is about 2". Does this seem right?.. it seems to stick out a long way past the transmission ( 2 1/2")?

Is a 2" engagement enough to keep the drive shaft running true on the splines?

Thanks Al
 
Are you replacing the original drive shaft or did you have a special one made ? What did you give the drive shaft shop for measurements. Remember the rear needs to travel. I would like to see another half inch in the transmission but your setup should work. IMHO
 
jimvette59 ... I asked for a driveshaft that was 61 7/8" long (ceter of u joint to center of u joint, with 3/4 " of slip. It came out closer to 61 5/8", with about 1" of slip.

I had it made because there was no power train in the truck when I got it, but it is "stock" setup with an 8Ba and a 3 speed top loader.
 
My stock shaft had 1/2 - 3/4 inches of slip when sitting on the tires unloaded. When I installed my T5 had the new shaft built with the same slip. Yours should work ok if you don't have too much wear on the inside of the yoke. With no more spline contact than you have it could vibrate. Not guessing - experience. Thought I'd never find the vibration.
 
Ford part number was 21C 4841 for the slip yoke.
Overall length of the shaft, minus the yoke should be 64-7/16 inches. THat's from outside to outside, not center to center of the u-joint like nowadays.
THe yoke measures from center of u-joint to end of splined end 5-1/8 inch. Spline should be full length of inside length of yoke.
Yoke is 1-1/2 OD . From snap ring to snap ring groove is 3-15/32", 16 splines, U-joint cap is 1-1/16 " OD. Spline ID is 1-1/32 and OD is 1=11/64" . Spline has 1/8 " spacing.
All this info is for an F-1 with a LD 3 speed trans. THere were some with the HD 3 speed, which had a different yoke.
Hope this helps
 
It should work fine, I had the same setup in mine. Those 3 speeds have a short output shaft and yoke.
 
This is where mine sits. The arrow points to the point it travelled to in normal driving (not fully loaded). Over an inch of travel available.
 

Attachments

  • Final Slip Yoke.jpg
    Final Slip Yoke.jpg
    158 KB · Views: 118
Ross F-1 ... I will post a picture of mine tomorrow. Yours looks to be about an inch further in than mine. That is what I was concerned about.

I took it for its first ride today (no cab, or front clip etc) . It seems to work OK, don't see any wobble, but I'm not going fast enough to create any vibration.

The front yoke is what the TX shop found, based on my output shaft and oil seal dimensions so I don't know if it is a Ford part , or something else .... but it fits in the hole OK.

As I said earlier, the "shiney" part on the yoke is about 3 1/2" long, and about 2 1/2" is showing when it is connected to the differential.

As an aside, there is a lot of movement in and out as you accelerate, and decelerate of the yoke. .... probably an inch in total.
 
Ross, Barry ...
Here is my setup without a cab or front clip. As you can see it is about and inch further out than yours. Barry ... the slip yoke I have is about 4 1/2 in from center of U joint to end of splines.
 

Attachments

  • F1 driveshaft-2.jpg
    F1 driveshaft-2.jpg
    52.1 KB · Views: 108
Yep, I wouldn't drive it like that! If the end of the splines gets past the seal, you'll be in a world of hurt, and it looks like that could happen. I'm afraid adding an inch or so the the DS is going to be expensive, too, I needed that and was told the only right way was a new tube.
 
Ross F-1 said:
Believe it or not, certain powerglide yokes are the same spline and OD, and about an inch longer. http://www.dennysdriveshaft.com/c75_general_motors.html
That is how MTFlat adapted a 9" to his F-1.
Click to expand...

Mine was sorta like that.

I have the 3 spd HD trans which uses a driveshaft like the F2/3. The output shaft has the U-joint bolted to it which puts the slip joint on the front of the driveshaft. This makes adapting rear ends infinitely easier than what you guys have to go thru.

I picked up a longer slip joint/yoke at a local driveline specialty shop and it was made there I believe.
 
Sorry Tim, I didn't realize that. Maybe I'm thinking of someone else? As I recall the Powerglide yoke is 6" long. That's still not an ideal solution because of the overhang on the output shaft.
 
Maybe I asked the wrong question at the beginning of this thread. What I should have asked is if anyone knows how deep the slip yoke can go into the back of the transmission before it bottoms out. Mine appears to be only about 2 inchs or so. Unless I have something internally interferring with it, when fully bottomed I have 1 1/2" of slip yoke visible protruding beyond the seal. The output shaft extends beyond the seal by about 1". So at best there is only about 3 in of engagement with no slip allowance.

After making allowance for say 1" of slip, that makes the minimum engagement only about 2" ... not very much as you have indicated. The end of the yoke is very close to coming out of the seal, and the only thing left is the portion of the output shaft that extends beyong the seal.
 
I'd swear mine goes in until the yoke hits the seal face. I wonder if your speedo drive gear has come loose? There's a snap ring that holds it in place, as well as the rear mainshaft bearing. It came out of the groove on mine, let the speedo gear slide back 1/2" or so.
 
OK .... maybe that's it. I'll check it tomorow. Gonna be some pissed off if I intentionally bought a "short" drive shaft.


Thanks
Al
 
I went and measured a F1 shaft I have, weld to weld on the tube is 60 inches...I had cut it off at the front weld, so can't measure U-Joints to U joint...but yours appears to be shorter than factory shaft.
 
Ross ....

I think we are on the right track now. I looked back at some measurements I made on the output shaft when I was re-doing the transmission. From the back of the C clip to the end of the splines is about 3.3 in. Therefore if nothing is stopping it, the yoke shoud go in 3.3 in. not the 2" I'm getting. Either there is something in the transmission stopping it , or the yoke I have only has 2" of splines ........ The plot thickens!!
 
When I traded a four speed for a regular 3 speed in my avatar '48 F-1 I had to change the mount, u-joint, yoke and driveshaft. When I went looking for the driveshaft I consulted the Ford truck parts manual which also showed the length I needed (I'd look it up but the books aren't available to me right now). I found what I wanted leaning against a barn in rural Maine - you have to keep your eyes open in this hobby! I strongly recommend that you consult the Ford truck parts book(s). It all went together fine and does not show the long length of machined surface that yours does.
 
You must log in or register to reply here.
Back
Top