Wrong Driveshaft?

[Mike R.]

The driveshaft that came with my 69 BB automatic trans car is 29.5" from the center of one u joint to the center of the other one. With the engine, trans and rear suspension mounted I cannot get the driveshaft in with the trans yoke all the way in (I even tried taking the ujoint caps off.

What should the dimensions of the driveshaft be for a C3 with TH400 ?

Thanks in advance!

[Joe L.]

Re: Wrong Driveshaft?

The driveshaft that came with my 69 BB automatic trans car is 29.5" from the center of one u joint to the center of the other one. With the engine, trans and rear suspension mounted I cannot get the driveshaft in with the trans yoke all the way in (I even tried taking the ujoint caps off.

What should the dimensions of the driveshaft be for a C3 with TH400 ?

Thanks in advance!

Mike-----


The THM-400 driveshaft is supposed to be 29.5" from u-joint center-line to center-line. The manual trans driveshaft is 29.9".

Another check you can make is driveshaft tube OD. The THM driveshaft should be 2-1/4" OD. The manual trans driveshaft is 2" OD.

[Mike R.]

Re: Wrong Driveshaft?

Thanks Joe. I will measure the diameter and remeasure the length.

Mike-----


The THM-400 driveshaft is supposed to be 29.5" from u-joint center-line to center-line. The manual trans driveshaft is 29.9".

Another check you can make is driveshaft tube OD. The THM driveshaft should be 2-1/4" OD. The manual trans driveshaft is 2" OD.

[Mike R.]

Re: Wrong Driveshaft?

I think the problem is the yoke. Please look at the photo and let me know if this is the wrong one.

[Joe L.]

Re: Wrong Driveshaft?

I think the problem is the yoke. Please look at the photo and let me know if this is the wrong one.

Mike------


This yoke is NOT configured like the correct GM #3930827. I'm not prepared to say that this might not be some sort of aftermarket replacement for the correct yoke but given your experience with it, I would say it's likely not.

[Mike R.]

Re: Wrong Driveshaft?

Thanks Joe, the only identification on the yoke is SPICER. From photos in catalogs I am pretty sure this is a GM yoke but the wrong one. Another mystery solved and another step closer to completion.

Thanks again.

Mike

Mike------


This yoke is NOT configured like the correct GM #3930827. I'm not prepared to say that this might not be some sort of aftermarket replacement for the correct yoke but given your experience with it, I would say it's likely not.

[Wayne W.]

Re: Wrong Driveshaft?

The picture is a little dark, but the yoke does not appear to have the straps so you can remove the yoke. The Corvette has a removable yoke. You cant install or remove the drive shaft with that arrangement, unless you have either the rear or the engine out.

[Mike R.]

Re: Wrong Driveshaft?

Sorry, I thought is was apparant in the photo that it is the type with straps. Anyway, is has been determined that it is not for a Corvette.

The picture is a little dark, but the yoke does not appear to have the straps so you can remove the yoke. The Corvette has a removable yoke. You cant install or remove the drive shaft with that arrangement, unless you have either the rear or the engine out.

[Gary R.]

Re: Wrong Driveshaft?

I'm rebuilding a 69 BB 4 spd shaft now, it is 29.9 center - center.

[John H.]

Re: Wrong Driveshaft?

Mike -

The slip yoke should look more like the one in the photo below, which places the centerline of the U-joint trunnions closer to the end of the splined tubular section.

[Mike R.]

Re: Wrong Driveshaft?

Thanks Everyone, fortunatly for me, Tom's Differentials is right down the street and, not only did he have the yoke, he also had the lowest price too. Driveshaft in a and bolts torqued....check

Mike -

The slip yoke should look more like the one in the photo below, which places the centerline of the U-joint trunnions closer to the end of the splined tubular section.