i got off work at 830 in the morning today, and i live in washington. its really cold lately. neways.. i get in my car, let it warm up till its idling under 1k, put it in reverse, and start to pull out. soon as the car starts moving backwards, i hear a knocking. i stop and so does the knocking. i put it in first, pull forward.. and no noise. i put it back in reverse, and as soon as i start moving, a loud knocking. once again, i put it in 1st, drive forward, and no noise. so i finally put it back in reverse, start moving backwards.. and the knock continues as i continue in reverse. i stop.. put it in 1st, and drive away... no knocking. i drive home, about 10 miles, all the while.. no knocking or noise. i stop on my driveway.. put it in reverse, and i drive backwards.. and this time.. no noise. i drive around in reverse, and the noise doesnt come back once.

any ideas?
its a 2000 s2k with 63000 miles. i dont know when that last diff fluid change was.. but i just got the fluid to do it. also.. the weather just started getting really cold.

any suggestions at all would be really awesome.

 

This has happened to a buddy of mine. It only occured a couple of times on his 2003 s2k while backing out of the driveway. I'm sure he changes the fluids regularly. His S has quite a bit more miles than you as well.

 

was anything wrong with the diff or anything.. or is his car still running fine?

 

This happened to me a few times too. It happened before I changed the fluid. I changed my rear diff fluid since then though. My car is a 2004 with 90,000 miles. I havent heard it since.

 

Wait till it's cold again and do the same test again... if it happens then it's most likely the diff oil.

Then just check the levels or even perform a diff oil change... (never hurts)