70-4sp. driveshaft shoehorn

[Dennis D.]

Finally getting around to installing the correct driveshaft in my 70 4 sp, L-46.
I had a auto shaft in there, and other than having to use a joint with 2 sizes to fit the different shaft and yoke dimensions, it worked fine. It was a bit close to the shifter bracket on the crossmember, but it never rubbed.

I don't know why, but I thought the correct driveshaft was not only smaller in diameter, but also shorter. Well, just found out it's a bit longer.(I think that's correct now). Problem is, I don't think there's a way in hell I can get it in there. Maybe if I pull all the cups to get it in place, then put them back, bolt them in, it might fit. Problem will be the trans yoke isn't going to clear the back of that shifter bracket. Am I missing something here?

[Gordon Peterson #4961]

Re: 70-4sp. driveshaft shoehorn

Hi Dennis -
I'm a C2 guy, but we're talking basically the same thing here. My parts book lists the overall driveshaft length as 31 25/32" (tip to tip). The way this all goes back in is to slide the separate trans yoke completely home into the back of the trans. Then slide the driveshaft in from the front, between the pipes, toward the differential, and bolt the differential end up. Then raise the trans end up and pull the yoke out to meet it, and bolt that end up. I'm blessed with long skinny fingers, so I do not remove the front differential bracket. You might need to to get at those differential end u-bolts.
Pete

[Dennis D.]

Re: 70-4sp. driveshaft shoehorn

Gordon-Thanks for the reply.

I just can up from the garage. I did install the rear of the shaft, and bolted it in. That was no problem. To get the front in the yoke, I had to push the yoke in until it hit the shifter bracket. This still wasn't enough clearance. I had to take the cups off and rotate it into position. Then I put 1 of the cups on and finger tightened the strap/ bolts. Tried to retate the shaft to bring the other end around but the rear of the yoke hits the shifter bracket and the shaft won't rotate.

I checked the shaft length, right on 31 25/32 end to end. Seems to be 29 3/4 center to center joint. I also measured the length from the mounting serface of the rear flange and the mounting surface of the trans yoke. Get a tick over 29 5/8". Quick math gives about 1/8" interference.

Everything lines up from the motor mounts, trans mounts, shifter to trans. The rear has never been out and doesn't appear to have moved or shifted at all. The trans is correct with the right tail piece.

[Gordon Peterson #4961]

Re: 70-4sp. driveshaft shoehorn

Wow! I have probably 1/2 - 3/4" of "play" that allows me to adjust the yoke to wherever I need it during the install. With the yoke pushed all the way into the tranny, I can still rotate it completely without interference. It sounds like the tranny may be out of position - shifted back? Has your car ever been hit? Or maybe there is a difference between the C2 and C3 in this area?

Pete

[Dennis D.]

Re: 70-4sp. driveshaft shoehorn

I can't push the yoke all the way into the trans because it hits the shifter bracket before that can happen. I seems the yoke is too wide. If it cleared the bracket it would go back at least 1/2" or more. Trying to find someone who can measure there yoke from outer hole across, and also outer hole diagonally, so I can compare. You wouldn't happen to know yours would you?

[Gordon Peterson #4961]

Re: 70-4sp. driveshaft shoehorn

Hi Dennis!

Just so happens I replaced mine last year, and I have the old one in my hand.

u-bolt holes center to center long side = 2 29/32"
u-bolt holes center to center short side = 1 3/8"
u-bolt holes center to center diagonally = 3 7/32"

overall length long side at widest point = 3 1/2"
overaall length short side at widest point = 2"

looks like a 1 1/16" trunnion cap diameter

Any hope?

Pete

[Dennis D.]

Re: 70-4sp. driveshaft shoehorn

Your unreal! Don't have all those dimensions yet(I willwhen I hit the garage), but of the ones I have:

Your 2 29/32 is 3.6" on mine

the 3 7/32 is 4" on mine

Huge differences. That piece wouldn't happen to have a spicer with a number on the back,(trans), side would it?

[Gordon Peterson #4961]

Re: 70-4sp. driveshaft shoehorn

Sorry I got sidetracked- only just getting back. I saw your other post, and it sounds like you are on the right track - GOOD LUCK!

My old beatup yoke has no numbers whatsoever.

Pete