About a month and a half ago I noticed a sound coming from just beyond the firewall (while driving) - sounded like a tire with a bulge in it - sound was speed dependant and on, off, on, off in nature.
Lately the sound has got louder. It's still speed dependant and still has an on, off, on, off nature. Thing is, it's also load dependant - as in, if I'm in third gear at 3000rpm and crest a hill and coast, the sound will go away momentarily or vary the speed between the typically rythmic 'on, off, on, off' nature. The other interesting thing that might help someone identify this for me is if I push the clutch in (but leave it in gear) the sounds volume decreases dramatically - but it's still there. If I take the car out of gear and coast, the sound is completely gone.
At first I suspected a wheel bearing. Thing is, I had just had the wheel bearing on the passenger side replaced, and that's where the sound seemed to be coming from at first. When the sound got louder, I couldn't tell if it was the passenger side, the driver side, or the tranny area that was causing it.
I recently created my own true short-shifter (not the one on my site, a new one) with a 1" (aprox) increase below the shifter ball. I'm wondering if this is causing too much stress on my tranny perhaps? Or maybe the fluid is low, or the fluid has overheated?

Any suggestions or guesses would be appreciated as my gut is telling me that my new shifter is possibly terminating my transmission. (live and learn...)

 

I doubt the shifter is doing it. I've had a custom short shifter on mine for about 3 years and no problems yet.

sounds to me like it's an axle, differential bearings, or a wheel bearing.
unfortunately, I'd have to drive it or ride along to be able to tell you much more.

 

if you say its not the wheel bearings......whens the last time you had your tranny serviced...filter,fluid change?..you can always try that as most people have seen it solve there problems...my friend had a problem where it made a noise like that but it was only while the clutch was not pushed to the floor...so when the clutch was engaged it didn't do it, but when it was put in gear or neutral it would come back...he had a bad bearing in his tranny....but without actually listening to the problem and seeing when it happens, i cant be sure about anything. Id lean towards checking the fluid and possible filter, fluid change

 

Thanks for the replys guys. Matt - did you lengthen your shifter below the ball, and if so, how much (aproximately)? Just seems coincidental that I made this custom shifter, installed it and not two weeks later this sound started and progressively got louder and louder. I would LOVE to know that it's not my tranny tho (not a job/cost I'm looking forward to you know).
The car has 320,000 kms on it and I've only been driving it for about 6 months now. I haven't changed the tranny fluid or had any trans service performed as long as I've owned it. Like I said, the only drivetrain changes have been a new passenger side wheel bearing and the custom shifter. Besides those changes, the only thing I can think of that may have caused this would be that I did not have the car aligned after I had the lowering springs installed (it tracked true and I experienced no vibration at highway speed and no abnormal tire wear after a few 500 km trips, so I figured why bother).
My theories are:
1) Bad drivers side wheel bearing (but it's a much smoother, less constant sound than other wheel bearings I've heard gone bad).
2) That the aligment was actually off, with excessive toe-out, which put undue stress on the drivetrain, causing something to prematurely wear.
3) That my custom shifter is applying too much, or even too little mechanical advantage to the transmission and is causing something to wear and/or causing the fluid to heat-up too much.
4) That my trans fluid level is low.
5) That with 320,000 kms on it, the trans is beginning it's slow death.
6) That I may actually have a cluth issue - and that I just can't identify it because I've never experienced this particular sound b4.

I'm going to have 2 or 3 seperate mechanics give me their opinions and combine that with the answers I've already got, and those I may receive, in an effort to track this problem down. I just pray to God it's not the tranny... (hope you're right Matt! )

 

I doubt it's the shifter. I forget exactly how much longer I made mine, but it's at least an inch. maybe 1.5".

think about it though... the only thing your shifter does it move a lever inside the tranny. when you take your hands off the shifter, there is ZERO stress on anything inside the tranny. it's just like moving the pivot point on a see-saw with a fat kid on one side and a skinny kid on the other. the only damage you can do is if you beat on it.

 

Ya, I know what you're saying Matt. What I'm saying (or wondering really) is if the increased lower length of the shifter increased the leverage to a point where that internal lever is actually being pushed too far, and therefor has caused some form of increased internal binding. You'll say no, that it's not, and I totally believe you - that's just what I was wondering b4.
One thing that you did mention was differential gears tho, and I'm wondering if that could be it - simply because of the fact that the sound only varies when the load, or vehicle speed abrutely change (going down a hill or quick off the gas). The speed at which the sound does it's off, on, off, on thing does NOT vary depending on the gear I'm in - which would support your theory that the trans has nothing to do with it. Now I'm just wondering how I managed to screw those up???
Other possibilities (that I alluded to earlier) are that the alignment has created too much stress on the front hubs and that perhaps I've caused the bearings to actually begin destroying the hubs? (does that even sound plausible??)
Correct me if I'm wrong, but if I had a bad drive shaft (which I have experience with), the noise would (eventually anyway) be most prominent in turns or when the suspension was very active - like a bumpy road? If so - that's not it. And if it were simply a wheel bearing, the sound would be costant, would it not? Neither of these things would diminish in sound level when I push the clutch in, or disapear altogether if I take the car out of gear at speed.
So for the worst sound level, the car just has to be (1) in gear (2) with the clutch engaged (as in, not pushed to the floor) and (3) moving - at any speed - at any temperature.
This is a new one for me!