Archive for August, 2015

61 to 64 and 65 to 68 Driveshaft Info:

Friday, August 28th, 2015

By popular request, here is info on certain driveshafts used in 61 to 64 Catalinas, Grand Prixs, Bonnevilles and Star Chiefs.  Remember that Catalinas and Grand Prixs share the same wheelbase (119″).  Bonneville and Star Chiefs are the same (121″).  These measurements are center of u-joint to center of u-joint on the driveshaft.  On to the info:

Catalina/Grand Prix:

3 and 4 speed:  59 11/16″ length, driveshaft diameter 3 3/16″

Hydramatic:  58 1/8″ length, driveshaft diameter 2 13/16″

Bonneville/Star Chief:

3 and 4 speed:  61 1/2″ length, driveshaft diameter 3 7/16″

(big thanks to Bill Hall for providing this info!)

Hydramatic:  61 1/2″ length, driveshaft diameter 3 1/4″

65 to 68:  All driveshafts, both 4 speed and Turbo 400 Hydramatic are the NOT same length!  And diameters are different.  The automatic driveshaft must be shortened by 1 and 9/16″.    You can always tell the automatic yokes as they are REALLY long.  Too long for a 4 speed.

Here are some pointers….I ALWAYS have my driveshafts balanced when they are out.  I recently found my own 4 speed driveshaft for my Catalina BENT in three place when the shop went to balance it.  They were able to put it on a lathe and turn it straight.  Also, now is the time to change out your u-joints.  About $15 at O’Reilly.  Do not buy the Heavy Duty u-joints there unless you drag race your car.  They are hard to install as well, too big.  Let the driveline shop determine what u-joint is correct for your front yoke.  Sometimes they take an adaptor u-joint depending on your application.  If you are using a period correct 61 to 64 T-10 in your 4 speed car (short or long shaft),you will need to find a 16 spline yoke.  Chevys use the same yoke on the manual transmissions (3 and 4 speed).  Some shops can convert an early T-10 into 27 spline yokes.   Hydramatics use two different yokes depending on if it’s a Roto 200 (SlimJim) or a Roto 275 (Bonnie/Star Chief).  They interchange with nothing.  If you go to a Turbo 350, Turbo 400 or a 200R4, make sure to get the correct yoke for that transmission.  When you car is sitting on the ground with the driveshaft installed, you want about 3/4″ of yoke showing out the back of your transmission.  Any less and you’ll beat the rear seal and bearing out of the transmission when you hit bumps.  I always sandblast my driveshafts before having them worked.  Look closely for cracks on the u-joint mounting eyes, missing or lifting up weights and sub-standard welding.  I DO NOT recommend you cut or lengthen your own driveshaft yourself.  Take it to a quality driveline shop.  Hope this helps!  LK  8/28/2015