Bought a 99 k2500 burban yesterday, 5.7 it had no speedo from the beginning and initially shifted pretty hard in every gear. Then after I bought it and driving it home it didn't want to shift outta first and when you let off the gas it acts like neutral. Then just as fast as it starts acting up it goes back to shifting hard. And when it shifts hard into od the rpms initially go 2-300 rpm lower then when shifts complete. The shifter is broken off the column u have to jam a screwdriver in to shift it. And the key is also stuck in ignition (dont know if they matter) my abs light is on I've read many many pages. But very little of it was with 3/4 tons and 4l80e. And none of them came n went. So far without fail its shifted if u hold it to floor it will wind up to 56-700 then shift fairly decent actually