Re: Threads and torque Twin Ultramatic

Posted by fred kanter On 2011/3/21 20:02:36

BAck in the 60's and 70's my brother and I worked on many Ultramatics (or Ultraumatics??) both cast iron and aluminum.
I do not recall any factory notices of any kind recommending lower torques for the bell housing to aluminum case bolts. We never encountered a stripped hole and always torqued to spec.

In most cases Packard was very thorough and with the troublesome Ultramatic if stripping had been common I would think they would have addressed it, for sure those tranny's were disassembled and reassembled more often than most other makes.

Member Rocky says that holes were previously stripped at 20-40 ft lbs. If so, someone was doing something very wrong. Fasteners are to be torqued dry, with no lubricant.
If the threads or under the head of the bolt are lubricated they will go to a much higher clamping force than intended and perhaps will strip the aluminum. Food for thought.