I believe the proper spelling is "Truckstell". They were a private company that made various heavy-duty items for sale to dealers, to install on new vehicles at the customer's request. There was a Truckstell overdrive unit that was available as a dealer-installed option on some trucks in the 40's and 50's, as well as other custom items.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!