03 g35 6mt stock everything. i know that the shifter feels very ingaged with the transmission and i like that but ... when i let off the gas is any gear around the speeds of 60-70 mph and begin deaccelerating i get a burst of a vibration in the shifter which is noticeably abnormal from the average feel. the vibration never occurs during acceleration and only occurs a few times a day during slowing down. Almost feels like the diff is causing it. i changed the trans and diff fluid a months ago with genuine nissan gear oils thinkin mayb it could help. the vibration only last a few secs and isnt accomodated by any noise ... just feel in the shifter. car drives great, shifts great except a small grind to 3rd when its cold ( but thats a sync issue i believe, goes away when car is warmed up ). Let me know if you have similar issues and how u resolved them, thanks

 

Hmm I cant say quite what it is without driving it my self but look into this

http://www.vibratesoftware.com/html_...e_Problems.htm

 

The car doesn't jerk when you give it gas after letting off the gas? How clean is your throttle body?

 

no the acceleration is perfect and the vibration is only felt not heard through the shifter. that link is very helpful and ilustrative. thanks alot xxhotelcrazyxx. My guess would be that if it is something with the diff then its most likely the bearings having play causing the gears not to mesh right. the car has 83k on it, i just replaced the sparkplugs and all the fluids. as for engine everything sounds and feels great. just this small short vibration that happens during the deacceleration which in my opinion is deff caused by something in the drivetrain. again it only happens once or twice a day and last for mayb 3-4 secs between speeds of 60-80mph. tell me what do u think.

 

Did you gap your plugs when you installed them. Im still thinking its somewhere in the drive train if it only does it when you let off the throttle. (When there is no load on your differential)

 

i got pregapped ones from nissan. u know i think that there is still load on the diff, its just in reverse direction. what im trying to say is instead of the drive shaft driving to speed up the rotation of the diff gears, during deacceleration, the diff is actuall resisting the driveshafts (motor and tranny) effort to slow it down. so even though not as much load as accelerating, there is still a load present during deaccelerating - see my train of thought? due to the fact that those are helical gears in there connecting the driveshaft to the diff, if the input bearing was developing wear, it could create play in the gap between the two input helical gears. what do u think

 

I know what your saying. But there isnt as much as a "drive load" on the diff as there is when your decelerating vs accelerating. The gears in the transmission will take most of the load during acceleration and deceleration. Takes more of the load than the diff.

 

yea i hear ya, i dont have any drivability issues with this as of now so ima wait and see i guess if anything bad comes of this. im expecting the sync for 3rd to eventually wear out soon so ill be using my extended warrante on a new transmission or a rebuild, prolly new one would be cheaper for the dealer.

hey u think the universals in the drive shaft could have a part to play with this vibration? there are 3 of em.

 

I think anything is a factor when it comes to the drive train, its one of those things you will just have to chase down from the tranny to your ring and pinion.

 

i totally agree, thats for the link and ur opinion, much appreciated

ps. thats a nice looks car u got there as well lol

 

Thanks, let us know if and when you find out what it is.

 

new observation on the vibration. turns out that its not necesarilly the speed of the car but the speed of the engine that the vibration occurs in. i realized that at deacceleration in pretty much every gear once the engine rpm gets down to 2700 rpm the vibration occurs and continues until just about 2400rpm and then dissapears. the frequency of the vibration (hz) gets higher in lower gears. what i mean is it feals more corse in 6th and 5th gear but in 4th 3rd and 2nd it thins out as if the part that is causing the vibration is speeding up. in first its really hard to distinguish the vibration due to the very agressive deacceleration and the very high frequency of it. but im sure its still there. any ideas?

 

Have you tried reving the engine and holding the rpms where the vibration occurs with the car parked to see if you can duplicate it vs while driving?

 

never occured to me to do that yet since i wasnt aware that it did it in all the gears but i will tonight and will let u know. what do u think it could be if it does duplicate the vibration as well as wut it could be if it doesnt? let me know thanks

 

I would want to say a harmonic balancer but that would be at an extreme. Letss see what happens when you rev while in park. How many miles are on your G again?