Driveshaft Vibrations wont go away! HELP

[S14ajmiller]

I have a 1989 240sx trunk. It was origionally an automatic, and was converted to manual. I did not do the conversion. Everything that the car had was put on before I bought it.

The origional problem I have had and cant get rid of is that when letting off of the gas while driving, there is a buzzing sound and some vibration. This problem gets worse when crusing 70mph or above on the gas or not.

We have changed the diff, also an axle, and that didnt change the problem. Also we found that the gearbox that was used in the manual swap was a 91, and the driveshaft was from an 89. We changed the shaft, it lessened the problem for a while and now it is coming back........ I am out of ideas.

I am wondering what you guys think it could be. Is it a problem with the trans relating to the manual swap, or mabey even the subframe in the rear? The 2 subframe bushings were swapped out for aftermarket if that helps. Let me know what you think! This will test your nissan skills so have at it!!

[Newcastle82]

Hmm.

A lot of times when that swap is done a pilot bushing isn't used in the crankshaft. That will definitely cause a little vibration going down the road, because as the transmission input shaft spins, it's not being supported at the very ened by anything - it's just rotating freely inside the engine.

I would say pull the transmission, pull the clutch/plate off, and look for the presence of a pilot bushing. If there isn't one, install one! =)

[S14ajmiller]

Thanks for your response! I will try that out. Any other guesses from anyone else are welcome...... When the problem is fixed, Ill will post who had the right answer

[S14ajmiller]

bumper

[Fenvy]

I have the same EXACT problem.. woudl like to know how to fix it

[catchit89]

I have 89 240 auto there is a harness just before transmission that holds shaft in place with upper and lower bushings make sure bushings arent wore out are that the bracket isnt bent also the vibration will loosen the nuts better fix it soon are you will looking for afull shaft mine did it for about 2 wks till it sheared everything does it mostly when you take off. maybe this will help like they say it can be anything with out looking at it later

[Amad18]

i have a 240rb20det...and im not sure if the guy that had it before me...swapped it from a auto to a manual or what...but i have the same problem as you guys..but it feels like the vibration is coming from the back..or something..im not sure...

[blackbeltclub99]

I think it may be a bad bearing in your driveshaft where the drive shaft mounts to the car.BTW Amad18 did you get your 240 from rb240 on here?