Drivetrain vibrates and whirrs ONLY under DECEL?!
 

ok, i have an 86 NA GXL, 5-speed, 150k miles, and after i went driving tonight, (not too hard at all)) i all of a sudden have NEW NOISES! i hat new noises:(

There are a few symptoms, here we go:

The most noticeable symptom is a new high pitched whirring noise coming from the tranny/clutch ONLY when engine braking during deceleration. before there was the usual light whirring of gears which was mostly drowned out by the engine noise and my medium loud exhaust, but now, if you slow down using ONLY the engine(cut throttle, leave in gear, coasting) theres a Big whirring noise that is VERY audible over the engine/exhaust. it seems to be worse in the lower gears, especially first. IE: if i'm going 25mph in first, and let of the throttle to engine brake, WHIIIRRRRRR!!!!! and the tone of the noise lowers with engine speed (which is directly related to tranny speed, i know) it gets quieter in 2nd and 3rd.

also, stopped AT IDLE there's is a noticeable raise in the volume of the drivetrain that sounds like it's coming from where the clutch/flywheel meet. With the clutch engaged and the tranny out of gear at idle, there's a semi-smooth whirring noise that gets quieter when the clutch is disengaged. before it was a smooth ALMOST inaudible whir. Plus when stopped, at 1150-1300rpm, theres a metallic, slightly lumpy whirring noise from the motor end of the tranny, kind of coming from the forward inner side of the passenger footwell, and i also get some lumpy engine vibration then too.

also, at idle with the car stopped, if you turn the steering wheel one way or the other to a certain degree (maybe 15-20degrees, not much) the wheel shakes, like it's tugging back at you a little,and the idle dips by about 200-250rpm. as far as i can tell, this symptom goes away even at low speeds.
so to summarize,

-MUCH louder tranny noise ONLY under engine braking, engine speed dependant.
-slightly louder tranny noise at idle with clutch engaged, quieter but not gone with clutch disengaged.
-lumpy vibration/whirring from behind dash between 1150-1300rpm.
-slight resistance/tug on steering wheel when car is stopped, idling, and wheel turned 15-20 deg. idle also dips a little, and engine vibrates a little.

i hope smebidy has some ideas...
i'm planning on changing my oil/tranny fluid tomorrow, we'll see if some royal purple in the tranny helps.

bump

somebody has to have an idea?

The whirring noise is your throwout bearing riding your pressure plate. It is riding way past normal so this is not a good thing. RX-7s have been known to eat up clutches this is usually how it happens. It rides the pressure plate and leads to premature failure. -Gabe

can i replace just the throwout bearing?

To me it sound like you whole clutch assembly is going out, if it's only a throw-out bearing that is bad, there shouldn't be a loud noise when clutch is disengaged, as the release-fork will pull the throw-out bearing away from the pressure plate. It could also be a bad release fork(although I've never heard of on breaking)

-MUCH louder tranny noise ONLY under engine braking, engine speed dependant.
this sound more like a clutch problem, might need to replace the clutch.

-slightly louder tranny noise at idle with clutch engaged, quieter but not gone with clutch disengaged.
This sound like a bad throw-out bearing

-lumpy vibration/whirring from behind dash between 1150-1300rpm.
possibly a bad pilot bearing?

-slight resistance/tug on steering wheel when car is stopped, idling, and wheel turned 15-20 deg. idle also dips a little, and engine vibrates a little.
sounds like a bad power steering pump, check to see if there are any leaks in the power steering pump.

Yes you can just replace the throw-out bearing but you might as well check all the clutch assembly while the tranny is out.

thanks guys, i appreciate the help,
i'll start pricing clutches, but does anyone have suggestions on what kind of good clutch to get, i dont need to handle alot of power, but i'd like something a LITTLE stroger than stock, I also want good street driveability, oh, and i'm poor too, so price is an issue.

thanks again guys

oh, and theres one more thing, when the engine is starting up, right after it ignites and catches and starts to go on it's own, maybe for about a second, something thuds against the body of the car 3 or 4 times, then goes away, and it happens when i shuit the car off too? any ideas, maybe bad motor mounts? thanks again

oh, and still interested in clutches i shoudl look at, good but cheap preferably.