Transmission Noise????

99oldstyletahoe · May 26, 2002

Hello All,

New to the site, but love what I've seen so far. Hope you can help with a new problem. We recently purchased a 99 classic body style Tahoe, 5.7L, Auto, 4x4. It has about 40k on it right now and we recently noticed a noise. When you mash the throttle a "flapping" noise pulses along at crank speed. It happens at various speeds when the RPM's are over 2k. The noise cannot be duplicated when the tranny is in park, nor can it be heard in neutral with the vehicle moving or stopped. I tried all the gears and it could only be heard in 3rd and and Drive. It only happens after the fluid reaches normal operating temps. Could it be the lockup torque converter? It's due for a fluid change so it might be a hydraulic problem related to the filter. It has me confused. Please help??

carguru · May 26, 2002

Welcome to the forum. Have you checked to see whether there is something such as the exhaust pipe touching the drive shaft or at least in close proximity to it when in park? I have heard of a couple with bent pipes that made the noise described. It could also be the tranny mount being loose. It sounds to be that it only occurs if the drivetrain has some load on it...enough to torque it over slightly. Good luck.