C2 Driveline U-bolt Torques (confirmation)

[Wayne M.]

Both '65 AIM and '65 Shop Manual Supplement call for 14-18 ft.lbs for the U-bolts on both ends of the propeller (drive) shaft and the (small block) half-shaft U-bolts at the differential pinion(s) [even though the differential U-bolts are larger than those of the driveshaft].

This torque range seems low -- heck, my torque wrench scale starts at 20 ft.lb. Also, the big block differential pinion cap bolts call for more than double (40-50 ft.lbs) the U-bolt torque.

Is this 14-18 ft.lb correct ?

[Duke W.]

Re: C2 Driveline U-bolt Torques (confirmation)

The snug fit trunnions/yokes take all the torque. The U-bolts are just 5/16"-16 (maybe some have fine threads) to keep the trunnions from popping out of the yokes, so, yes, those torques sound correct, and my 63 AIM says 14-18 foot pounds.

If you've ever worked on an aluminum engine you learn very quickly that you need a small torque wrench - a 300 in-lb is good since this will cover most small torque jobs up to 25 ft-lbs, and torque wrenches are generally most accurate at about mid scale. Above that you use the normal 150 ft-lb torque wrench that you use for chassis fasterners, cast iron engines, and vintage railroad equipment.

Duke