I have a 91 240SX with 128,000 miles on it right now. I bought it last year with 114,000 miles and it had a noise of a bad bearing (whining/whirring noise) ever since I got it. I finally got myself to look for the noise and it's coming from the the transmission bellhousing.
My guess is that the input shaft bearing is bad, but I really don't know for sure because I don't have experience with transmission diagnostic and repair. The noise occurs in neutral, 1, 2, 3 gears and can be heard when at 1200-1500+ rpm. It gets higher pitched as the RPMs go up.
Before I got the car, it had recently had a clutch change. I do not know much else about the clutch job but I am suspecting that whoever changed it was too lazy to change the pilot bushing and might not have changed the throwout bearing as well.
If this problem can be identified, what would I have to do to repair it?
5pd transmission bearing noise?
well you need to determine if it is clutch related or trans internal noise. does the noise occur in 4th gear? does the noise exsist when the clutch is depressed? it it doesn't occur with the clutch depressed i would say your T/O bearing is not the source. usually a pilot bushing is heard first thing in the morning then goes away after a few clutch operations while driving. so that would leave internal trans bearings/gears. in order to replace the bearings you need a hydrolic press to remove them. does this noise go away in 4th gear but return in 5th during normal driving. if so i would say its countershaft bearings. if its determined it is internal bearings i strongly rec replacing them all. let me know if your gonna do it and i will attempt to walk you through the procedure and tell you where to take precations during dissasembly.
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Touchdown038
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I am getting that transmission "whirring" sound also... I have a brand new clutch, and I replaced the pilot bushing and throwout bearing when I did it. The noise happens when you let the clutch out in neutral, or when you are in first through third. At this point I have no idea what it is, but it's not hurting performance at all so I'm just letting it be.
HachiRoku wrote:At idle rpm range, it's silent and will whine/whirr as the rpm goes up, usually at 1500+rpm is when it becomes noticeable.
I only hear the noise when revving in neutral and gears 1, 2, 3.
Clutch depressed/released, the noise is present when revving.
At gear 4 and 5 it's not noticeable.
you are saying the noise is present at a stand still with the clutch in shifter in gear off idle?
NISTECH wrote:you are saying the noise is present at a stand still with the clutch in shifter in gear off idle?
thats what he said
you guys can rule out the pilot bushing because it would only occur with the clutch pressed when the input shaft is spinning at a different speed than the crank/flywheel
try this:
put the car in first, and make sure the parking brake is on, this will make sure the input shaft isnt moving. press the clutch in all the way, and rev it. if the sound still occurs its likely something with the pilot bearing. if not you know its from the flywheel forward (maybe in the engine).
if the sound doesnt happen then its something with the transmission, possibly an input shaft bearing....
if your in neutral and you rev the engine and play with the clutch and the pitch/intensity of the whirr changes then its probably the throwout bearing or transmission.
hope this helps. correct me if im wrong on anything
NISTECH wrote:you are saying the noise is present at a stand still with the clutch in shifter in gear off idle?
basically, it will make this noise at standstill and driving
neutral revving whether or not car is moving, when clutch is either up or down.
gears 1, 2, 3 while driving, progressively quieter as you go up in gear.
not noticeable while driving in 4 and 5 gears, but possibility that in those gears, noises while driving may cancel out this noise?
it's virtually silent while idle when coasting or at standstill....just no noise basically
I'll try p00t's ideas and see what would happen from there, but I think it's likely the noise will still be there
the point poot and i are getting at is( if the car is not moving AND in gear AND the cluth pedal down), the transmission should not be turning internally at all. If the noise is still present at that point the internal trans components is NOT your problem. it would have to be T/O bearing forward. If the noise goes away when those specific steps are taken then it is internal trans bearing noise your dealing with.
ok...after going out for another drive, i've noticed that the noise is present in all gears while driving, just that it's less noticeable when driving faster because of other noise drowning it out.
i've tried what p00t suggested and the noise is still there...but i noticed that when the clutch is down and the engine is cold, there's that bearing noise as you rev up, and when you release the throttle, there's this quick and almost silent slapping/scratching sound regardless of whether or not car is in gear.
best description of it would be bunch ball bearings in a cylinder falling from one end to the other end making a sound as they collide at the end of the cylinder.
when the clutch is up, it doesn't make the slapping sound when releasing the throttle after revving. same for when the clutch is down on a hot engine.
i guess that means the transmission is ok?
i've tried what p00t suggested and the noise is still there...but i noticed that when the clutch is down and the engine is cold, there's that bearing noise as you rev up, and when you release the throttle, there's this quick and almost silent slapping/scratching sound regardless of whether or not car is in gear.
best description of it would be bunch ball bearings in a cylinder falling from one end to the other end making a sound as they collide at the end of the cylinder.
when the clutch is up, it doesn't make the slapping sound when releasing the throttle after revving. same for when the clutch is down on a hot engine.
i guess that means the transmission is ok?
well this noise you are describing now sounds like pilot bushing. BUT this noise would go away in most cases after driving a short distance. did you try the steps i said on a warm engine. in gear with clutch pedal down and not moving rev the engine is the noise you hear still there remember engine warm when the "ball bearings in a cyl" noise is not present.
then its not internal trans noise your hearing. when pushing the clutch in and putting it in gear while stopped the trans stops moving including the input shaft. a T/O bearing noise should go away when the pedal is released. so that leaves pilot bushing. if your gonna go in and do the pilot bushing you should inspect the clutch and T/O bearing as well.
Re: 5pd transmission bearing noise? (HachiRoku)
so what did it end up being? im having the same problem so i would like to know. thanks