Hello!


I just bought a 2003 996 Turbo yesterday evening - I'm stoked. During all of the test drives she drove excellent, but when taking a tight 180 degree sweeping freeway on ramp at speed (accelerating) I could feel a slight grumble/shudder under my butt and in the steering wheel. It also made this same grumble/shudder when making a U-turn while getting hard onto the gas at the end of the turn.


Question - can you feel the AWD/PSM system working? Would it cause this grumble/shudder while sharp turning and accelerating? Other ideas?


Straight line driving no issues. As a noob to Porsche AWD I might just be a little touchy to all the new noises and feelings of the car.


Car has 59,000 miles and otherwise checked out with the mechanic when I had the PPI done.


Thanks in advance for the help!

 

Based on my experience with my 03 Turbo -- now over 110K miles -- the drive train is a bit sensitive to high throttle openings/engine loads at low RPMs. It protests some mainly with a noise that at least sounds unpleasant to me and reinforces in me the desire to avoid subjecting the car to the same conditions again and thus avoiding the noise.


At higher RPMs though the AWD doesn't make itself known in any way that is obvious to me.


However, what you are experiencing may not be from the AWD system.


In sharp turns - and a U-turn qualifies -- the inside front tire can scrub. It does this because it is lightly loaded, and due to the geometry is not in full contact with the pavement, and if the tire is worn and heat cycled and thus harder it has less than optimum grip to begin with.


The above could occur even on the freeway on ramp which you posted is a tight 180 degree turn and you took it at some speed.


Check tire pressures. Be sure the tires are not over (or under) inflated.


Feel the tread surfaces looking, err feeling for signs of odd tread wear, like feathering or roughness that could be due to alignment.


Just so you know the front drive is via a viscous fluid coupling and delivers anywhere from a minimum of 5% torque to 40% torque to the front wheels/tires. My info is the full 40% is delivered at high speed (~150mph or higher).


The few times I've driven my Turbo in marginal traction conditions (snow) even when I gave the car some throttle and broke loose the rear tires (summer tires) I didn't get any real indication the front tires were getting any real torque.


Due to the circumstances I was not able to spend any real quality time in the snow, and given I had summer tires on the car that was probably a good thing.

I note you had the car PPI'd and it was checked out by a mechanic. I only question then if the mechanic is experienced with Porsches and AWD Porsches and specifically Turbos.

 

Thanks! After some mor driving and looking at the wheels at full lock i think its a combination of what you describe about low RPMS and the tires look like the rub at full lock. In all other aspects this i cannot wipe the smile off my face!!

 

UPDATE:

Worn transimission mount was the real culprit, nice to have that sorted!