Hello everyone I hope someone out there can help me... I have a 2000 Impreza 2.5RS 5MT.
Last night I drove my car home from town and parked it , I didnt drive it all day today and it was windy and single digit temperatures . I started my car tonight and drove it out to go see some family , I immediately noticed that whenever I released the throttle i would hear a loud whirring sound from beneath me , at first I thought it was exhaust related , but revving at a stop sign while not moving produced no ill effects . it only happens while engine braking is happening , i also get a sudden clunk from somewhere behind me now , have I destroyed my rear differential or my transmission? The car drove 100% last night when I got home , what happened?? If anyone could point me in the right direction it would be much appreciated THANK YOU for your time and reading this thread

 

That's pretty typical of Subarus to make that noise. It is basically your tranny. If you have a short shifter and/or tranny mounts, that noise might be louder. It also gets louder as your tranny wears out with time. It also depends on the gear oil you are using as well as outside temps, which affect your gear oil viscocity. I would not worry about it, but if it just because hella loud all of a sudden, I would drain gear oil and check for anything unusual ont he magnet/drain plug as well as the color/smell of the gear oil itself.

 

A week and a half ago, a new abnormal noise appeared It only happens when decellerating and is most noticable in gears 1-3 at low rpms (1K - 3Krpms). Ive had the car for 2 years now (52K miles) and this is the first time Ive heard it. It sounds like a 'whirring / vibrating' noise....kinda loud

I jacked the car up, no visual damage to cv boots/axles/suspension ect.... I ziptied any loose plastic covers that might be vibrating (some of the cheap plastic snap/bolt things were loose/broken)...didnt stop noise. Tranny fluid is full, last changed at 36K miles (about 16K miles on the fluid now). I changed the rear diff fluid at the same time, but havent checked the level yet, no leaks or anything.

Car shifts and drives like normal, but Im worried about this new noise. I will change the fluids again as Imprezer mentioned, but does anyone have any other ideas?

 

If it whines when deaccelerating in neutral, your rear differential is shot. Mine's getting swapped out in the shop right now.

 

No, only when its in gear.

 

If it whines when deaccelerating in gear, then you have no problem at all. Every single manual-shift car I have driven (at last count, six) whines in second or first while slowing to a stop.

 

Yeah, the whine is normal, its always been there. But thanks for the idea.

The new noise seems like an odd rattle/vibration/twang of something loose associated with the drivetrain decelleration...I dunno, maybe Im just obsessing about it??

But I have never heard this noise before, it doesnt sound good or normal...

 

My only other thought on this would be a chipped synchro, which is of course not what you wanted to hear because the only way to check this is to crack the case on that transmission. Your only hope to really diagnose this is to have a good shop mechanic (someone with 10+ years experience) ride along with you or drive the car and listen to it.

 

That would suck if it were a tranny problem...or a good excuse to justify some RA gears. Im really hoping its just some stupid rattle from a loose plastic cover or something. It drives fine and the shifter feels good engaging into gears.

It will be on a lift soon, so hopefully I can diagnose it then.

 

Turns out I had multiple issues that were contributing to the annoying noises....thankfully none were drive train related. These were found when I had the struts and springs replaced and alignment done Fri & Sat --

1 - Blown rear strut
2 - Bent front passenger side control arm
3 - Seized driver and passenger side tie rods
4 - Abnormal tire wear on snow tires causing extreme vibrations
5 - Multiple broken plastic clips w/ loose splash guards

All the 'weird' noises are gone but I still need to replace the tie rods and R control arm to get the alignment perfect.