edman

My 1995 Z28 automatic has been making this noise for several thousand miles now. Whether in gear or neutral, engine on or off, as it rolls forward, it makes a clicking sound that increases with speed. At 10-30mph it sounds like a gear drive timing set through my transmission tunnel. By 50mph, it is so fast that it dissapears into the exhaust note. Slowing to a stop, it becomes more annoying as speed decreases. Is it something within my tailshaft, part of my driveshaft, or possibly within the rear end? With engine off on jackstands, I cannot spin my wheels fast enough to get the sound. Has anybody anywhere ever had and fixed this kind of sound?? thanks, edman

Injuneer

On the chance that this noise is being produced by the tranmission, I'm going to "copy" this post to the "Drivetrain" forum. We have a reliable trans rebuilder that drops in once or twice a week and offers help.

edman

I have been driving the Camaro to work for a year now, still makes the whine sound. It is strictly based on driveshaft speed, coasting or driving, forward or backward, engine on or off. The speedometer works properly, the transmission shifts properly. I currently have the driveshaft off, and although the yoke universal rotates extra easily in all directions, I cannot feel any actual play. The yoke has an integral balancer on it, but nothing appears loose. I ran the car on jack stands without the drive shaft, put it in gear, went up to 30mph, and the loud whine is gone, but is replaced with a faint sound, and the speedometer did bounce up from 5 mph to suddenly 30 mph. I have not actually checked the
VSS, but plan to pull it and have a look tomorrow. When I ran it with the driveshaft attached and up on blocks, using my cellphone to record it, the noise was loudest at the universal rather than the housing. I know there is a reluctor on the tailshaft, and that the VSS is close and picks up a signal, so am thinking that with yoke not attache, perhaps the clearance has changed with shaft droop? I plan to have a new universal joint pressed on at a shop tomorrow, but am fearful that the noise will magically reappear when all is back to the road! If anyone ever had this odd condition, I would like to hear from you! Also, is it at all possible that the yoke splines made this noise somehow? Should I resolve the problem, I will post a follow-up! thanks , Edman

edman

Well, apparently I can't fix anything! I had a new universal pressed on to the yoke, only $13 labor at a driveline shop. They thought old universal was good, as did I, but that's where all the sound was from, so had to take a chance. The vss came out with no marks, was hopeful something was hitting it, so put it back in. Installed the yoke turned for different splines, and added some grease on the inside. Drove 200 yards down the road with no whine sound, made a u-turn, and started hearing a faint sound, and by time I was home, the loud familiar sound was completely back. Very strange. Now thinking of pulling shaft, adding grease again to see if it copies the routine? Very strange.

edman

Well, the whine/click sound is back! I removed the driveshaft, then ran engine and this time the whine sound was back, so driveshaft is innocent, and noise is in the tailshaft housing (was not there last time I did same test). So the tone wheel must be touching the VSS to make the noise, yes? No solution figured out yet, and I am searching VSS styles and types.

edman

I finally resolved my noise! I did pull my VSS out many weeks ago, and did not see any witness marks at that time, but still guilty as charged! This time, I saw that an always "loose on sensor" mounting tab allowed the sensor to "roll" slightly in the mounting bore, which was why the reluctor wheel was touching it. Also, before I installed the brand new VSS, I took a flat file to the metal tabs and noticeably reduced their projection. All buttoned up and no noise now! How it started: My automatic transmission was completely rebuilt three years ago with performance internals. The old VSS was re-installed, but apparently the metal mounting tab became loose on the factory installed attachment rivet. Vibration allowed the sensor to turn, and the reluctor wheel caused a "blower whine" sound to exist for the next three years of time ( I drove a different performance car for two years). I almost miss the sound! thanks for your ear, Edman.

Injuneer

First time I've heard a problem like that. Thanks for posting the follow-up.