so im almost finished the rebuild on my sm 420, and i noticed these electrical contacts on my gearshift when i was installing it to test it, being as my other electric switch is somewhat temperamental id like to find the missing piece(s) to use the one in the knob. has anyone found a source for this? my usual guy hasn't ever seen one like it apparently.
I've seen the Chevrolet vacuum push/pull and the Eaton red knob push/pull switches (https://www.amazon.com/Four-Seasons-35802-Speed-Switch/dp/B000DCNFAM), but never seen the knob the OP has on any Chevrolet TF trucks...must have been a GMC thing...could it be Timkin related?
I think Timken electric two speed rears is correct. I meant to add that to my reply that the trucks I've seen with that switch Did have Timken rears.
The 58 task force GMC in my signature has that switch only in 5 speed. Has Timken rears,
Maybe someone has late fifties GMC parts book that can confirm "Switch knob assembly" with what rear end option and even a GM part# which greatly helps in searches.
I had a 2 speed shifter on my 1957 550 series. It was a 1998659 which was superseded by a 1998658. They were both obsolete while I had the truck. I replaced them with an Eaton 032861 push pull switch. Google the Eaton part number and you will find them for sale all over the place. I had a 3 speed Eaton on a 1964 model that used a switch on the gear shift. I found one of them on eBay.
