Adding the 700R4 to the 48 2 ton was bound to produce a speedometer error since that trans was probably set up for a 3.something rear.
But the difference is so much that it is presenting some problems in measuring it.
Tried it today on the town roads with a GPS speedometer app on the cell phone. It looks like 25-30 mph high. To get it really accurate so I can order the right part I need to get a long flat road to use mile markers and a stop watch. This is New England, that only exists on interstates, limited access highways etc.
However the speedo only goes to 80. So I don't want to peg it lets say I hold it on 75. The real speed will be 50 or less. That's going to be really hard to go between 2 exits without being run over!
Looks like the the other 2 measured speeds will be even slower so I still have to find a flat mile on a back road somewhere,
