Or, just do it the dumb way. Sometimes the dumb way is the smart way.
And that would be to mark the tires in you nice straight driveway, mark the driveshaft, and roll it along until the tire does one revolution, while counting the driveshart turns. Then of course, 3-3/4 driveshaft turns = 3.73, or 4-1/8 turns = 4.10s.

Note: never do this with the truck running, especially with your wife at the wheel while you've got your head under the truck.