Posted by Ed Fulton on Saturday, December 14, 2002 at 7:30AM :
Hey guys, I hope you'll tolerate one GMC speedometer question. I recently changed the differential in my '88 GMC pickup from 2.73 to 3.42 ratio. Can I correct the speedometer by changing the electronic sending unit at the rear of the transmission? I called a speedo shop and was advised that they will have to "burn a chip", which I assume means they will have to replace a chip. Appreciate any help in this regard..