1993 90s Problems

[WestCoast1]

Hi,

I appreciate any help you folks can provide. I drive a 1993 Audi 90s that I have had for about five years. I recently had two issues come up almost simultaneously (related?).

The first is a rhythmic rattling or tapping that sounds like it is coming from the gearbox when the car is started and is in park or neutral. There are about three or four 'taps' per second. The noise stops when I step on the brake or put the car in gear. It does not seem to affect the driveability of the car.

The second issue is that the rear brake lights went out, although not the window-mounted brake light. The light bulbs are fine, and so is the fuse.

Any ideas?

Thanks,
Dan

[ctesla]

Dan,
was on sabbatical over the holiday, and just happened to check the non-specific, rather than older vehicles.
the rattle, as you step on the brake goes away? and you say "p" or "n" so I guess it's an auto?
well, it could be a VSS (vehicle speed sensor), since it gets its feedback from the wheel/ABS sensors, and the minor tap/vibration smooths out as the brake pedal is applied. VSS @ Audi is about $30-40.USD, and is located on the driver's side of the trans, forward of the tailshaft (if it's AWD)
BUT--- I think you should drive the vehicle up on ramps, and then even jack up and jack stand the rear, and get underneath.
the 90 series had AMPLE heat shields, and one of them could have rusted or come loose, and braking eases the rattle because the engine idles differently, due to vacuum, and the tailpipe doesn't smack the shields. if excess mileage, and/or it is rusted, or broken, I'd just remove completely. the shield that is behind the trans is the most likely culprit, as it wraps the tail of the trans, and goes up into the well around where the "Y" pipe converges to one pipe. you'll get better gas mileage if you rip this one out and pitch it, as it has probably collected in its vast cavity above it an additional 40lbs of dried mud and road debri.
as to the brake lights, if not the fuse, could be a stop light switch going bad, and blowing the fuse, or if you live in a humid climate, water/moisture in the back light lenses.
hope this helps,
chris
nrt racing
[email protected]

[WestCoast1]

Thanks, Chris. I've also been on vacation and just returned to see your reply, but I'll check out those suggestions.