So my tacoma is a 5 speed 3.4l v6, when i start from a dead stop and accelerate quick, there is a bad grinding noise coming from what seems like the rear diff. also i do not know if these two are related, but when i am in neutral, slowing down from 20 MPH, there is a light click/knock about every few seconds. just one little click. i know that i need to replace my rear u joint, could this cause any of these issues?

 

If you know that a u-joint is bad, why don't you replace it before it damages the driveshaft, and then you will know if your noises remain, or not.

 

X2 or before you lose your driveshaft on the interstate.

 

replace the u joint and see whats up after that. i had weird squeaking/ grinding sound from my truck one time. i got under it and greased every zirc fitting i could find and it went away. it turned out the slip yoke on the drive shaft was dry.

 

Make sure that your differential has fluid. If its leaking then the grinding noise might be the gears due to low fluid. Also, check your rear tires underneath, the inside, for differential fluid splatter on the tire. I had to redo the bearings on mine due to this problem.