HELP, knocking noise on my 4R!

[Bravo1]

2000 4R 2wd SR5. I get a knocking noise heard only at very low speed around 10 mph or less while coasting. It seems to go away when I accelerate or come to a complete stop. At least I can't hear it then. It is a steady rapid knock and doesn't get faster or slow down with speed.

Other than the noise, the engine seems to be running fine and no problems braking, etc.

I have driven with my head hanging out the open window to try and figure out where its coming from but so far been unable to tell. It's beginning to drive me nuts but I hate those diagnostic trips to the shop (kinda leaves the door wide open for them...) Any ideas from anyone?

:thanks:

 

[JeremyH]

My guess would be that your driveshaft needs a rebuild. It is likely dependent upon speed, but reaches a resonant quite zone above 10 mph. When you accelerate, your rear axle rotates slightly (points the pinion upward) and is likely pushing the driveshaft up out of that resonant zone.

You can pull the driveshaft and inspect/grease the u-joints or simply replace the u-joints.

 

[Glockwarrior]

Is it a faint noise?? If so mine is making same noise at the same times you mentioned