1985 4000s

whenever i get to about 3500-4000 rpms during a moderate to hard acceleration i begin to drastically lose power accompanied by a terrible rattling/grinding noise. as that sound starts i immediatly up-shift and as the rpms drop the sound goes away and power comes back.

thing is that when the rattling begins it doesn't go away when i let up off the throttle.

 

Stick or Auto? Does it happen in all the gears? What happens when you rev the engine in neutral?

 

it's a stick. happens in most gears but i haven't been able to check if it does in 5th cuz of traffic. when i rev it in neutral it does it too and for the first time today it also screached when i started it up and i just turned the car off.

The street that i park on has a pretty steep slope and the entire area i live in has a lot of hills.

i also have an oil leak that i haven't been able to find the source of but i suspect the seal around the oil sump. i really need to do some more investigating but that's what i've got so far.

 

Without hearing the sound it's hard for me to say but we can probably eliminate the transmission. If the noise is somewhat high pitched here is what could be making the noise;

Timing belt idler pulley (very common)
Alternator
Water pump
AC compressor
Power steering pump

With the exception of the timing belt you can remove each of the belts one at a time to see what is causing the problem.

 

i know what you mean about the sound cuz i've never heard anything like it but thanks for the help.

on what it might be i have a feeling that it's the timing belt but where can i get one? do i need to order one through an Audi parts dealer or can i just go to any Schucks or Napa and get one?