1997 Chevy Suburban, (custom ordered through Chevy, in-case that makes a difference), 4:11 gears, 454, 4 x 4, built to tow big stuff. Transmission shifting, was revving instead of shifting. So off to Transmission shop, rebuilt. Vibration at idle and driving, all RPM's after rebuild. So off to our regular mechanic. Checked Harmonic Balance, wires, plugs, all OK. Back to transmission shop. Disconnected transmission from motor, runs fine. Transmission re-connected back to vibration idle and driving. - Signed, sad wife missing my Burb