I just finished replacing both U joints today to cure a vibration at gear changes and also since they were 142,000 miles old. Afterwards,there is a vibration present at 55 mph and up to 65(as far as I went due to the vibe)and it is constant. The shaft was checked for straightness and was found to be so. Balance is also good. There was a small amount of play in the tailshaft noticed while I was replacing the tailshaft housing seal that I assumed was normal. Also the front (old)U joint was almost dry when it was removed. I also adjusted the pinion angle on the spohn torque arm to 0 degree to try and correct it with little improvement.
The tranny also has a poly trans mount which has increased the amount of "feel" in shifting and vibes. I'm going to swap to a new OEM mount in the morning to see if this helps at all. Am I looking at a tranny rebuild or can this be fixed without an overhaul? The tranny was rebuilt at 30,000 miles and a shift kit was put in at 79,000 with no problems out of it ever since. Can anyone help?


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Mongoose-NCTGA-1990 Pontiac Formula/305 TBI-700R4 with Edelbrock Performer TBI intake,TES headers,and STB,K&N,MSD-6AL,Holley laser shot coil,Accel Extreme 9000 wires,Jet Stage 2 chip,TCI shift kit with corvette servo,Richmond 3.73 gear with Auburn 3 series posi,high flow cat,SLP 3" cat back,Eibach sportline springs,Energy Suspension poly throughout,Lakewood LCA and adjustable panhard bar package,SSM subframe connectors,IROC wonder bar,Tokico 5 way adjustable struts and shocks,Autometer electric fuel pressure gauge,Alpine,JL Audio,MB Quart,92 GTA taillights,92 GTA aero wing and hatch,Steve Spohn LCA relocater kit and torque arm,MacEwen White face gauges,84 T/A cold air induction air cleaner,Grant Formula GT wheel.