humming and vibration on 2nd gear

[jdm538]

i have a problem with my s13 and no one seems to know what it could be. in 2nd gear when i let go of the gas my car makes a loud humming noise and has a slight vibration, it also does it in third but not as bad. i have changed the diff, driveshaft, subframe spacers, axles, clutch, changed the oil in my tranny, and new motor/tranny mounts. what is wrong with my car?

on top of that it's very sluggish from first gear. help me YO!

[D1GP]

did you change out the pilot bearing when doing the clutch?
is the driveshaft completely balanced?
have you replaced the carrier bearing?

[jdm538]

doubt it's the driveshaft since i changed it and same prob, i think it might be the pilot bearing. will anything go wrong if i dont change the pilot bearing?

thanks for the reply

[supreme_1]

i have the exact same problem, but my car isnt sluggish. it just vibrates when i go past 3k. i know my input shaft bearing is bad tho. does yours hum when the clutch isnt depressed no matter what gear?

[jdm538]

mine only hums when it is in gear with my foot off the gas and clutch.

[jbuckley]

check the bolts on the driveshaft , i had this problem a while back and turns out one of my bolts had backed out :duh: .if you just put in a new oem 240sx 2 piece driveshaft id suggest checking the middle bearing on it(forgot the real name for it)

[zaneithan]

im experiencing the same thing, i DID NOT do the pilot bushing when i did the new clutch/tranny but it looked in good shape upon visual inspection, ill be changing out my driveshaft tonight so perhaps its that

[jdm538]

is it bad to drift on a worn pilot bushing? what can happen?

i dont really have time to take off my tranny before the event.

[racepar1]

The noise is NOT your pilot bushing, period. Your pilot bushing will ONLY make noise when you are stopped with the trans in gear and your foot on the clutch. The rest of the time your input shaft is turning with the flywheel so the pilot bushing has no or very little movement. Just a tip, ALWAYS change your pilot and throwout bearings when you do a clutch. For your vibration check your harmonic dampener (crank pulley) as well. If the rubber isolator is bad that could cause the kind of vibration you are talking about.

[Z U L8R]

what about the driveshaft's center bearing support brackets, do you think you have them in upside down?

[cruque]

Hi I have a similar problem. My trany starts huming in fith gear. I been told is because Im low on fluid(i put 2 quarts when i should really put 4) or is because that gear is just bad.

[jdm538]

im glad it isnt the pilot bushing, kinda doubted it since the sound was coming from behind.. i just change all fluids in both tranny (2.5qt) and diff (fill till it drips) it still makes the nosie and slight vibration. how can you tell if the center bearing is bad while it's off the car? I already put a different driveshaft and it still has the same prob... so the 2nd driveshaft might have a bad bearing to?

[Dream240]

Have you tried to lift the rear end of the car and put it in 2nd/3rd gear? Does the car still make the noise while running? You can put the car in all gears under these conditions, to see if you've got a loose component or faulty bushing somewhere.

Give it a try, BUT MAKE SURE BOTH WHEELS ARE OFF THE GROUND!!!!

[mmdb]

Have you checked your tires? You might've flat spotted them.

[Z U L8R]

in the middle of the driveshaft is the center bearing. it has rubber around it and it has two metal half moons that go around it and hold it to the chassis with 2 17 mm bolts. the half moon side that has the 2 raised circles is the side that touches the chassis. the smooth side is the side that the bolts go through. is that how yours is bolted up? if not, it's upside down, and that's your problem, flip it over.
Dave =]

[jdm538]

just checked the half moon and tested the car while the rear on jackstands and i couldnt see what the noise could be coming from. could the vibration be from a broken axle?

[Z U L8R]

i've had a lsd cause a vibration before. it was a 180sx rear diff, but instead of the 5 bolt flanges and axles, they put in the stock nissan 6 bolt stab axles and cv's and it made the car shake.