Mario Meireles

Hello ,

I recently purchased a 996 C4 Titronic.
I come here to ask for your help, if possible.
The car makes a strange noise when I drive at low speeds, about 50 km/h. The mechanic has already disassembled the front transmission and has not found anything strange, we have already changed the transmission shaft bearings and the noise continues.
Has anyone had this problem, do you know what it is?

Here's a video with the metallic noise you hear.

Many thanks!

Mário

Porschetech3

Strange noise indeed !!! .............Make a longer video under different scenarios to give more clues .....

Ie .. keep the noise going as long as possible.......ie .. does the noise occurs at same speed with different RPMs/gear? ie.. does noise change due to left or right turns? ie... does the noise change under braking/accelerating? ie.. does the noise re-occurs at twice the speed? ie.. does the noise only occurs hot/cold engine temp?

Mario Meireles

Porschetech3,

The Sound come and Go, it’s difficult to keepet, long time.
No matter if is cold or hot, it always appear at this speeds, and only a this speeds….

EVOMMM

When was the tranny and diff flushed and which oil did you use

Porschetech3

I would say your viscus clutch is failing by the sound and description .... Part # 6 in the diagram......

Have your Tech install some "electronic ears" to the tube that goes to front drive axle and have a listen......




Pos Part Number Description Qty. Needed Price 1 90012401302 Screw Plug M 18 X 1,5 1 $8.92 (1) 90012401302 Screw Plug M 18 X 1,5 1 $8.92 2 99733230900 Joint Flange 2 $262.05 3 99911345441 Shaft Sealing Ring 40 X 60 X 9 2 $22.00 (3) 99911345441 Shaft Sealing Ring 40 X 60 X 10 2 $22.00 4 99633231100 Circlip 2,5 X 20 2 $5.55 5 99630107100 Bleeder 17 X 12 1 $8.35 6 99633902102 Viscous Clutch 1 $2,119.60 7 90023417400 Support Washer 20 X 28 X 2,0 1 $3.23 8 99904102101 Circlip 20 X 1,2 1 $3.23 9 90012401401 Screw Plug M 18 X 1,5 Pm 1 $16.06 (9) 90012401401 Screw Plug M 18 X 1,5 Pm 1 $16.06 10 99970745540 O-Ring 123 X 3 1 $24.61 11 N90366001 Torx Screw M 8 X 36 For 996.349.010.02 Getrag 630.0.0130.00 Old Version 4 - (11) 90038514101 Torx Screw M 8 X 40 For 996.349.010.03 Getrag 630.0.0173.00 New Design 4 $12.81 13 N90366001 Torx Screw M 8 X 36 8 - - 00004320923 Grease Liqui Moly Pu 53 / Wdr 50 Gr. X -


FWIW :: Viscus Clutch damage is usually caused by running mismatched tires front to back.... The 4WD model 996's are very very critical to run correct size tires of equal wear...It is an OEM recommendation is to NEVER replace the front tires without also replacing the rears at the same time with correct sizes....