Driveshaft and input yoke

[Edward M.]

My 56 input yoke doesn't go into the tranny far enough with the driveshaft installed (see pic). The driveshaft is from a 1960 Corvette, and measures 34 1/2 inches center to center. The input yoke is the long Corvette type (4 7/8 inches?). The transmission is a 57 passenger car powerglide, so it is the same length as the 56 Corvette powerglide.

Any ideas on what the issue is here? I am about ready to get a longer driveshaft.

Yep, that is my custom shifter attachment bracket.

[Joe L.]

Re: Driveshaft and input yoke

My 56 input yoke doesn't go into the tranny far enough with the driveshaft installed (see pic). The driveshaft is from a 1960 Corvette, and measures 34 1/2 inches center to center. The input yoke is the long Corvette type (4 7/8 inches?). The transmission is a 57 passenger car powerglide, so it is the same length as the 56 Corvette powerglide.

Any ideas on what the issue is here? I am about ready to get a longer driveshaft.

Yep, that is my custom shifter attachment bracket.

Ed-----


All 1956-62 Corvette driveshafts were functionally the same. All 1956-62 Corvette transmission yokes were functionally the same. So, assuming that you actually have a 1960 Corvette driveshaft and a 56-62 Corvette yoke and there has been no "relocation" of the engine and rear axle mounting, any fitment problem must be related to the transmission.

[Edward M.]

Re: Driveshaft and input yoke

That makes sense Joe. One person suggested that I might have a 58 or later passenger car powerglide. The date codes that I saw on the transmission are 1957, but I don't recall what month.

Are 1958 and later cast iron passenger car powerglides shorter than Corvette powerglides? In other words, would a 58 or later passenger car
powerglide account for this situation?

[Joe L.]

Re: Driveshaft and input yoke

That makes sense Joe. One person suggested that I might have a 58 or later passenger car powerglide. The date codes that I saw on the transmission are 1957, but I don't recall what month.

Are 1958 and later cast iron passenger car powerglides shorter than Corvette powerglides? In other words, would a 58 or later passenger car
powerglide account for this situation?

Ed----Yes, I'm pretty sure that's the problem if the transmission/extension housing is froma 1958 passenger car. The 58-62 PASSENGER extension housing is 5" long. All 1956-62 Corvettes require an extension housing that is 7-1/4" long. So, that's why you're "short" if you have a PASSENGER 58-62 extension housing.

[Mike E.]

Re: Driveshaft and input yoke

Ed--
Great creativity in your shifter to tranny mount! An issue you may now run into, if your tranny tailshaft housing is too short, is that your shifter may come up in the wrong area when the body is set down. (Like 2" too far forward). Make sure you do the measurements and are assured that the shifter is in the right place before you start the body drop.
Let us know what you find!
Mike

[Edward M.]

Re: Driveshaft and input yoke

Ed--
Great creativity in your shifter to tranny mount! An issue you may now run into, if your tranny tailshaft housing is too short, is that your shifter may come up in the wrong area when the body is set down. (Like 2" too far forward). Make sure you do the measurements and are assured that the shifter is in the right place before you start the body drop.
Let us know what you find!
Mike

Body is on the car. The only thing missing is the transmission tunnel cover, which is in the trunk right now. I'll check it and let you know.

[Edward M.]

Re: Driveshaft and input yoke

OK, here is what I know so far. The transmission is a 57 passenger car powerglide. The tail housing is 7 1/4 inches long. The yoke is 4 7/8 inches long. The part of the yoke NOT in the transmission is 2 3/4 inches, so (doing the math) that means that 2 1/8 inches of the yoke are inside the tail housing.

The transmission tunnel fits over the opening and the shifter is just about perfectly (slightly shifter to the left by 1/4 inch) positioned.

Now, given all of this, do I really have a problem here?

It has been suggested that the driveshaft will move in and out a significant amount due the the overall suspension travel. I suspect that it is out now about as far as it will go.

I'll jack up the car from the frame and see if the driveshaft moves out any more as the rear suspension extends. Then I will load up the trunk with about 200 pounds of junk and see what that does to the driveshaft position.

Any further sugestions on what else I should check?

[Joe L.]

Re: Driveshaft and input yoke

[quote=Edward McComas (9316);340233]OK, here is what I know so far. The transmission is a 57 passenger car powerglide. The tail housing is 7 1/4 inches long. The yoke is 4 7/8 inches long. The part of the yoke NOT in the transmission is 2 3/4 inches, so (doing the math) that means that 2 1/8 inches of the yoke are inside the tail housing.

The transmission tunnel fits over the opening and the shifter is just about perfectly (slightly shifter to the left by 1/4 inch) positioned.

Now, given all of this, do I really have a problem here?

It has been suggested that the driveshaft will move in and out a significant amount due the the overall suspension travel. I suspect that it is out now about as far as it will go.

Ed-----


If you have the 7-1/4" extension housing and the driveshaft is 56-62 Corvette and the yoke is 56-62 Corvette, all should be well. In that case, I'd say the yoke insertion must be normal. It's been so long since I had any related experience with a C1 that I just don't remember how it was.