I have recently noticed a clicking noise from the front differential on my 2000 Chevrolet Silverado when traveling at low speeds (under 10 MPH, but I'm sure it's always there, but it's too fast/too much road noise which makes it impossible to hear at faster speeds).
I know it's coming from the front, and I even removed the tire and the driver's axleshaft and rotated the shaft coming out of the front differential directly and I still heard/felt the clicking noise from the front differential.
So here's what I have eliminated/things I have tried
- It's not the wheel bearing since it wasn't turning once I disconnected the axleshaft
- It's not the inner or outer CV joints for the same reason as above (and I replaced it for good measure since I had it out... and it looked original)
- It's not the U-Joint coming from the transfer case because the 4 wheel drive was disengaged when I was spinning the axleshaft by hand which would not have turned the transfer case
- Partially locked 4 wheel drive/bad vacuum solenoid. I eliminated this by driving the car and putting it into 4 wheel drive. There was a definite shift in power but the clicking was still there. I only attempted this because I have heard that the solenoid can get partially engaged constantly, which might have explained the clicking.
Things I have yet to do
- Replace front differential fluid. I know this is an obvious one, but I didn't have what I needed to do it yesterday because I had originally suspected the wheel bearing. Also, on the advice of my wife's uncle, when I change the fluid I will check the old fluid for any signs of issues. I know to look for metal shavings, but is there anything else I should look for in the old fluid?
- Take it to my mechanic to check it out. I definitely trust my mechanic but I'm trying to find out is there anything else I can try changing/troubleshooting before taking it to my mechanic?