I have a question about the driveshaft in my 1969 GS400. When I was under the car replacing the pinion seal, I noticed that the driveshaft appears to be a 2 piece design. The car has the original Turbo 400 automatic in it. It looks like the attached pictures I found on the web, except not nearly as rusty. I'm not having any problems with it or anything, I just had a question about it and the design. Is the smaller part supposed to slide in and out of the larger part, or is there some kind of vibration dampening thing inside it between the 2 parts? This is the first GM A-body car I've had with a driveshaft like this. I wasn't sure whether to post this in the Slushbox or Gears section...
The smaller slips in and then rubber compound poured in and vulcanized from the factory. It is an isolation dampening design. (no, it does not slip in or out) Over time, the rubber will breakdown and the torque will eventually result in a twisting of the drive shaft halves and out of phase of the yokes, and likely vibration, or failure of the shaft if the rubber breaks completely loose. A new driveshaft can be made to your measurements and on your front porch in about a week to ten days for a few hundred dollars. And worth every nickel to do that on a shaft over 50 years old. I have had several made by Denny's Driveshafts. tech@dennysdriveshaft.com (800) 955-1872 Phone - Orders Only (716) 875-6640 Phone - Customer Service, Tech Line & Pricing questions
Thank you Michael, that's exactly what I was looking for! If I start getting any vibrations out of the drivetrain, I will look into replacing that.
REPLACE IT....That is 50+ years old....IT IS DONE. besides that shaft is rusted to heck. Give that drive train some love.... JD Race Jim
Seems Buick and Olds had that kind of shafts. Chevy used a balancer by the yoke. My SS Monte Carlo 1971 was like the damper balancer at the slip yoke.
I took my original drive shaft to a shop to have it balanced, and it was the same design as yours, but it looked a lot better They called and told me it was "twisted like a pretzel" I had a one piece shaft made. Get rid of that thing.
That's a good question. It's a little unclear in the 1969-70 Chassis Manual. Did all automatic equipped cars get the two piece design, and manual transmission cars, except the Sportwagon, get the solid one piece design?
Jim, thanks for the response. The shaft in the picture is not the actual one that is in my car. I pulled that photo off of the web for an example of the design. Mine is in way better shape. Since most of this car has been original thus far, I'm guessing that the drive shaft is original to the car, too. I think that Larry's comment was correct, that the automatic cars had the 2-piece and the manual cars had the single piece drive shafts. I had read somewhere else that this 2-piece drive shaft was only used in the 1969 and 1970 model years, as well. I just wanted to know how it was constructed and if the 2 parts were fixed together or moved (slid in and out).
Manual cars that I 've had are one piece. (68, 69, 70) My 65 Wagon had a 2 piece so its use went back to 65 at least.
