i have a 93 sc300 NA-T and i just did a 5speed swap with a w58...everything is installed and pulls fine BUT it has a very bad bump sound coming from the center where the shifter is...I know its the drive shift but i dont know why..the trans mount seems to be fine and center shift mount also...And when i say bump,i mean BUMP,Its like the whole car is shaking and going to fall apart...The more RPMs the worse it is..

 

Did you check the u-joint?

 

Like a dumbass i didnt but im pulling the diff out to weld it right now and ill check the u-joints

 

You know that the driveshafts are in balance, and have to be installed a certain way right? but yeh u-joints my next guess.

 

yup that also.

 

installed certain way????enlighten me plz fine sir......

 

If you ever noticed a small couple of square things on your driveshaft, those are weights. Think of your driveshaft as a wheel needing a balance. If you do not install it a certain way it will be out of balance. They either are welded or stickied on sometimes they fall off.

 

it could be coming from the carrier bearing , that bushing gets worn out and break and you hear a tumping noise fron the center console.

The U joints on the driveshaft will do that also, specially if the swap was from an old SC.

 

im thinking the carrier bearing but im pulling the driveshaft Saturday and check everything and ill take some pics//

 

Ok guys just to let you know..the drive shaft thing was my fault for rushing to get it together....if you know at the end of the drive shaft there is a rubber donut with 6 holes......lol i was only using 3 of them holes...so i had it thru the drive shaft and st8 to the diff......lol as soon as i jacked it up i was like ****...lol but thanks for the help guys..close thread plz