Tow vehicle question

You clearly have to adjust the speedo. But most vehicles use pulses from the VSS and then translate that via the computer into the analog speed displayed on the speedo. The shop can flash that in a couple of minutes to correct it. Most likely if you disconnect the battery, the shift points will work themselves out just fine as the computer monitors your speed, RPM and driving habits. By the time you have driven it for 30 minutes, it will be back to normal. I pull an 18 footer with my ranger all the time, 4.0 200hp v6, 3.73 rear axle, O/D off unless the roads are really flat, and it has zero problems with hills and excessive shifting2008 Pantera Classic2014 Mercury Pro XS 200

3.73 vs 3.23 will make a significant difference while towing. However, the 3.73s will also make a significant difference in gas mileage while not towing. I had 5.3s (4wd) with both 3.42 and 3.73 rearends and I saw about 1 mpg difference on like trucks with different rearends. As already stated in a previous post, I would not recommend towing in overdrive unless on flat ground at speeds above 65 mph, however that will make no difference in acceleration, especially when using tow/haul mode. As you probably already know, tow/haul changes the shift points electronically to stay in the torque curve of the motor and firms the shift. It also causes the transmission to shift at any slight grade. I tow quite a bit and have never seen the benefit of tow/haul mode.