I've never had pinging but did replace my carrier bearing. It had about 1/4" of up/down movement by hand. I doubt it's the carrier bearing. I'm at 225K miles, 01 Taco, plenty of 4WD time and never replaced anything else in the drivetrain (except CVs).Hate to revive an old thread, but I'm experiencing a very similar sound on my newly purchased 1998 Tacoma SR5 4x4 with about 265k miles. The previous owner just did a bunch of work (timing belt, transfer case/diff flush, etc) and lifted it 3". Wondering if the lift changed the angle of the shaft enough to create a "pinging" sound. The sound happens when I engage the gas pedal, let off of it, or create substantial front-to-back motion otherwise while in gear. Upon purchase the sound was not audible and developed after 2 nights of US Forest Service road travel (i.e., mild off-road activity). So far I have applied grease to the entire rear driveshaft, including the slip yoke, checked the u-joints for play, and am close to taking the entire shaft off and trying this third washer trick. Any reason I shouldn't and/or are there any better recommendations? I am also considering replacing the carrier bearing while I have the driveshaft off. Any constructive input is appreciated. Thanks in advance.