Carrera911

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

pszikla

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

Carrera911

The alternator?

the sound doesn´t change with the engine rev.
-it´s changing sound with the "wheelspeed"

Carrera911

Hi again

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

Hurdigurdiman

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.

silotwo

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.

Carrera911

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

//E

jasper

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.

Carrera911

What is the CPO ??

jasper

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.

Carrera911

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??

Hurdigurdiman

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.

washington dc porsche

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

Carrera911

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

washington dc porsche

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