I have a year 2000 Dodge Dakota, V6 engine, rear wheel drive, manual 5-speed transmission I am the original and only owner. Truck has only 60,000 miles.

For the first 20-40 minutes of driving, all is well. After this time I notice a decrease in power. On an Interstate Hwy grade, I may even have to downshift to 4th gear to maintain 65 mph.

I thought a brake was sticking, but on a slight grade, I put the truck into neutral and stepped on the clutch pedal and the truck rolled, so I don't think a brake was sticking.

Also, my wife once noticed some white smoke coming from underneath the truck, somewhat on the drivers side.

What do you think? Is there an easy test to determine if the clutch is the culprit? What else could it be?