4-speed conversion tranny-driveshaft yoke issue

[vegiguy]

In doing a four-speed conversion on my '73 Road Runner I had to get a different driveshaft yoke for the input onto the tailshaft of the A-833. The problem is the new yoke doesn't go in the tailshaft housing very far - maybe 3" at most - and of that 3" of insertion only 1 1/2" is spline to spline contact since the first 1 1/2" of the yoke doesn't have any splines at all in it. I'm going to have to subtract another 3/4" of spline to spline contact to allow for being able to clear and bolt the other end to the differential yoke when I get my driveshaft shortened so really the spline to spline contact is only going to be 3/4" which doesn't seem like enough. I'm wondering if I'm doing something wrong or if I should cut the 1 1/2" off of the end of the yoke since there isn't any splines there. I'm pretty sure I got the right yoke since the splines do mesh together some; also there aren't very many yokes to choose from to begin with.

Can anyone shed some light on this? Thanks.

 

[Bb70charger500]

Well I never had a problem let me shove a shaft in the 4 speed in the shop and see what happens ,this may or may not be helpful but is it an overdrive trans maybe they have different output lengths? I'm not sure not a trans guru anyone else want to chime in

 

[vegiguy]

Well I never had a problem let me shove a shaft in the 4 speed in the shop and see what happens ,this may or may not be helpful but is it an overdrive trans maybe they have different output lengths? I'm not sure not a trans guru anyone else want to chime in

It's just a standard A-833 - no overdrive.

 

[5.7 hemi]

Sounds like you have a burr on the splines. Put some anti seize inside the yoke and push it on till it stops, then tap with a dead blow till it bottoms out. You should be good once you can slide it easily by hand.

 

[Cornpatch MO]

I always think of the not likely things..Could the splines on the tailshaft , or on the yoke be twisted?
Take your tailhousing seal out and look up along the splines. Is there anything there that could be blocking further engagement? I expect you have checked down inside the yoke? Are you shure it is the right yoke? I think the splines do not go to the end of the yoke so that it is easier to get it installed...................................MO

 

[hangn0ut]

Look at another yoke. I have never seen a yoke splined like yours. Definately not a good idea for performance usage.

 

[Photon440]

When I did my swap from 727 to 4-speed, I used the same driveshaft, yoke and all. Wouldn't your original one work?

 

[vegiguy]

When I did my swap from 727 to 4-speed, I used the same driveshaft, yoke and all. Wouldn't your original one work?

No it's too small in diameter since the old auto trans. was the 904.

I think something is screwed up inside this yoke and that is the problem. About an inch down the splines inside it feels very rough and bumpy. I thought it was rust and it could be cleaned up, but I'm wondering if on a previous car it didn't get pushed into the back of the transmission far enough and it was so unstable it beat the splines inside the yoke out of shape. Also, the previous driveshaft it was on could have been out of balance, too, adding insult to injury.

I think it's time to look into ordering a new yoke. The splines on the tailshaft of the transmission feel very smooth and I definitely don't want to screw them up by trying to force a messed up yoke on it.