Belrix
New member
Well, looks like I'm keeping the 4Runner (1990, 4WD, 3.0 v6) for a while. Time to address the strange sound that's coming from the underside. It started a couple weeks ago.
At 35-40 MPH or so, it seems most audible. It seems to get louder when I slack off the accelerator some and the car is decelerating slightly. At 35 MPH it's about 2 beats per second, a soft scuff-scuff-scuff sound that makes a slight vibration in the floorboards. It gets faster and slower with the speed of the car. With the car in park, there's no sound at any RPM. The problem is somewhere in the drive train.
I just had the entire rear-differential reworked. New pinon seal, front flange and axle seals (there was slung oil around the underside of the car lined up neatly with the front of the diff). I also had the drums turned and the brake fluid replaced but that's probably not important. Sadly, the scuff sound persists. I can't think of anything that spins that slowly at 35 MPH.
I've also greased the entire length of both drive shafts. This seemed to reduce the sound at first but I think I was just damping it.
So, I was thinking about removing the front drive shaft to see if it would stop. That might indicate if the problem is in the front differential. Anybody know if I can run this truck without the front drive shaft?
Is there something else I should be looking for?
At 35-40 MPH or so, it seems most audible. It seems to get louder when I slack off the accelerator some and the car is decelerating slightly. At 35 MPH it's about 2 beats per second, a soft scuff-scuff-scuff sound that makes a slight vibration in the floorboards. It gets faster and slower with the speed of the car. With the car in park, there's no sound at any RPM. The problem is somewhere in the drive train.
I just had the entire rear-differential reworked. New pinon seal, front flange and axle seals (there was slung oil around the underside of the car lined up neatly with the front of the diff). I also had the drums turned and the brake fluid replaced but that's probably not important. Sadly, the scuff sound persists. I can't think of anything that spins that slowly at 35 MPH.
I've also greased the entire length of both drive shafts. This seemed to reduce the sound at first but I think I was just damping it.
So, I was thinking about removing the front drive shaft to see if it would stop. That might indicate if the problem is in the front differential. Anybody know if I can run this truck without the front drive shaft?
Is there something else I should be looking for?
