Hey guys, so i have a 1993 sc400, and ive put about 1500 miles on it since ive bought it, its now at 153,000 miles. Im having vibrations and clunking, but theyre faint. Ill explain in depth: Vibrations are at their worst in cold temperatures, and so is the faint clunk.the clunk happens when im slowing down and the transmission downshifts to the lowest gear under 12 mph, its not a loud clunk but its noticeable and not there when i bought it. i feel the vibration in the steering wheel and i hear an occasional ***** sound thats very faint and hard too hear when i slightly let off the gas, and slightly press on the gas. The ***** sound is only when im going 20 mph or above. The vibrations happen when its cold or the car hasnt completely warmed up, wether its in park or drive at approximately 1800 rpm. i know its nothing suspension related, car drives perfectly straight with or without pressing on the gas. Now, as far as stuff i know thats been done, full tune up, timing belt, all the middle mileage maintenance. First thing i tried was replacing the transmission mount, and it did get slightly better. but its not 100% like it was when i first bought it and test drove it. ive done extensive research and im trying as hard as i can to hold off on dropping a bunch of cash with a mechanic. ive narrowed it down too engine mounts possibly being somewhat worn, (i inspected them and they didnt look terrible or anything) the driveshaft center support bearing, or my valves needing adjusted, which is the least likely thing to be wrong according to the research ive done on this forum.
Any insight would be appreciated!

 

It sounds like a bad drive shaft center support bearing or even a u-joint to me also. However, it'll be best to get the car up off the ground and check for play in the drivetrain before jumping to any conclusions.