Rear-end Whine

Hi All Im new on this forum and also new 996 owner(had a 911 Carrera 3,2 -86 before) I have noticed a whine in the rear of the car that change the sound with the speed of the car, the sound is the same whether I have the clutch up or down, enginebrake or acceleration on any gear. To me it doesent sound like a pinion issue -what do you people say? can it be a wheel bearing? but its the same noice in any direction left, right turn or straight forward. BR Erik

hi Erik! having experienced the pinion gear whine, i would say that it is different from a wheel bearing noise which is more like a drone than a whine. Having said that, the pinion gear whine does change whether you are in gear or out of gear being more pronounced in gear. (and in gear it can be more pronounced in acceleration or more pronounced in coasting in gear). So based on your comments maybe it is more related to alternator or in that direction? Pete

The alternator? the sound doesn�t change with the engine rev. -it�s changing sound with the "wheelspeed"

Hi again I have the option "220 locking differential 40%" can that make som noice?

You are probably on the right track there. I havent read up on the differentials but I was wondering if the sound was maybe coming from that area. It's the only other moving part outside of the engine with teeth that could give out a whining sound.

This might sound too simple. Did you check your tires and tire pressure? These cars are really sensitive to tire pressure. I had a whine after a new set were installed, the rears were under inflated and the whine went away after I put them to the spec pressure.

Have to check the tire pressure then -there�s only 300km on tires so they like new -Michelin Pilot sport N3 //E

My first 996 developed a faint rear end whine *just* before the CPO ran out. The car had 70K miles IIRC. The good people at Roger Jobs in Bellingham stripped it down and rebuilt it and the problem went away. Not common issue, but it does happen.

What is the CPO ??

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Certified Pre Owned. It's an extended warranty that Porsche applies to used cars that it sells. The 2002 model car I bought in 2006 was CPO until 2007.

Checked the tire pressure today and I have 2,5 in front and 3 in the rear -same whine noise, its clearly a bearing but which bearing??

To make certain that it is a bearing you can jack up the car, engine off, release the hand brake (emergancy brake) and spin each wheel manually. You should hear the bad bearing. Another way is to open the windows and drive parallel too and close into a wall or building where you will hear the loud hiss/rumble of a bad bearing reflecting or echoing back to you. Then jack up the loudest side and check front and rear wheels by spinning them or taking them 3 and 9 oclock style and pushing and pulling them. Any play and thats probably the one. The front are easier to spin. Check out your brake pads and totar wear while you have the car on stands. Don't forget to CHOCK all grounded wheels when jacking cars up. You could ask a mechanic. He will pin point the bad one in minutes.

My guess its one of your tranny bearings. Been there done that.

yes but which bearing in the tranny? can be good to have a clue befor I take the tranny down.

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Mine was the main bearing, the $400 one, but while inside he changed most if not all of the rest from what I recall.

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who did you send your transmission to?

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I had a local indy rebuild mine.

did he replace synchros? how much was the damage if you don't mind me asking?

I've had a slight whine coming from the passenger rear wheel on my 02 cab C2 for ~6 months now. I've convinced myself that it's tire whine - but this thread has me wondering. My noise is apparent only when driving next to a wall and only from the passenger rear wheel. I jacked the car up and checked for wheel bearing play months ago and it was fine. I can try jacking the car up again and checking for rotational noise - anything else? Would the transmission bearing only make noise on one side of the vehicle? Thanks, Ben

Carrera911............Get a mechanic to give his opinion before thinking of dropping any tranny's. It just may be a wheel bearing still. The sound should be the same as you drive near a wall. If its louder on one side than the other, then its probably a wheel bearing. Knock the car out of gear and roll along next to a wall. You will hear it then if it is a wheel bearing.