What the heck ? My 1996 T100 4x4 has a whirring, buzzing from underneath, center of the truck, only when driving at 5-15 mph. And only after 5-7 miles.
Belts, muffler, heat shields, or low trans fluid ?

Where do I start ? Happy trails and thank you...Mike

 

Crawl under there and start looking for anything that could cause a vibration. Does anything look out-of-place?

 

Common area to look at is the heat shield on the crossover pipe. This can be easily fixed by grabbing the heat shield with some pliers and tweaking it.

 

check your front driveshaft also. The noise could be a knuckle going. Check your transfer case that it has fluid. another noise could be your speedo cable wearing out. but that would be infront of you not in the center under the truck.

 

Thanks guys- Checking tomorrow !