Last thursday i was at a trackday in france. Long story short, i've taken every turn sideways and at the end of the day my car made this whining sound which seems to come from the rear (probably the differential).

It sounds exactly like this (my car shows the same behaviour regarding throttle position on/off):[media]http://www.youtube.com/watch?v=0CK8zAAw4AA [/media]&feature=related

I drove the car like this for the whole day (minus the feint drifting on the straight section):[media]http://www.youtube.com/watch?v=3gSdH5FYqyg [/media]

The car has around 50k miles on the clock and is in perfect mechanical condition (except for this problem now). The whine noise is definately coming from the back of the car and the pitch is getting higher with increased speed, but not dependant on what gear i'm using.

My main questions:

- Is it the differential most likely?

- If yes, should i replace it right away or keep driving the car until the diff really stops working (car drives perfectly fine except for the noise)?

I'm asking this because i have another trackday planned this weekend but no time to get a new diff until then. Would i break anything except for the diff if i went to drive on a track like that? Or should i definately cancel the trackday?

Thanks for any advice!

 

After doing some more research, i understand this could also be some wheel bearing or the driveshaft?

 

If it sounds like an old roots blower it's the diff. If you act quickly you may be able to rebuild it cheap, but it may be a better option for you to just buy a used unit. I purchased a ap2 diff for $400 + $35 for the oem parts to swap the companion flange to an AP1. Listening to that video screams diff damage. It may be out of spec, but more than likely you experienced wheel hop and cracked a tooth. Drain the fluid and check it for metal.

 

Thanks for the reply!

It doesn't sound like an old roots blower. It sounds more high pitched in my opinion (and not as loud as in the video i posted, but the pitch sounds similar, also the on/off throttle behaviour is the same).

I've experienced wheel hop a few times, yep.

I've made an appointment at the dealership tomorrow to have them check it out. I'll post back once i know a little more details hopefully (i'm not a mechanic and even tho it's easy to do a fluid change of the diff, i don't have a garage where i could do it).

 

Nice driving!!

 

Haha, thanks... it isn't me in that video tho (simply used it as an example (it's the same track however)).

My drifts were not as perfect (i failed to link them together like in that video), but still not too shabby! They called me "the drifter" in the pitlane, haha!

 

driving like that for a long period of time is certainly capable of killing the diff on this vehicle. We have less than one quart of fluid capacity on this vehicle it might not be able to protect extreme conditions like that. After you get it fixed I'd consider a better fluid if you intend to keep driving like that, honestly you might consider an upgraded puddy diff. if you want to put the car through those paces again, I'm not sure an oem diff could ever keep up with that type of driving and you may find yourself in the same position again.

The other item could be a bad wheel bearing but that sound should oscillate with vehicle speed.

 

That video has me cracking up. I don't have enough fun with this car...

 

[QUOTE=JFUSION,Sep 6 2010, 03:05 PM] driving like that for a long period of time is certainly capable of killing the diff on this vehicle. We have less than one quart of fluid capacity on this vehicle it might not be able to protect extreme conditions like that.

 

That sounds like a ring and pinion that has shifted pattern. NOT bad necessarily.

Listen...take the back of the driveshaft down and check the nut on the dif drive flange. Extreme heat could have melted the nylon, causing the nut to loosen slighty.

If you can tighen it further, remove it, use red loctite, and reassemble.