skippermccoy

My wife was driving my car to work and it started to make this sound. I am not sure what it is.

http://youtu.be/KDv2nz23YGc

danglerb

When you say trans area, do you mean the shifter up front or the transmission in the back?

Sounds kind of like an exhaust leak to me.

NC928S4

Could be exhaust leak. Sounds like Torque Converter scraping on Torque Converter housing. Can you see any scrape marking when looking at the bottom of the TC housing cage. There is a 2”x2” grill at the bottom only 89. You might do a look see there.

Hope it’s nothing serious.

skippermccoy

It is from the very back by the transmission. I was in the process of trying to look through that cage area but my flash light was dead. Currently charging it. It has been one of those days.

Black Sea RD

It could be the rear flexplates that mount onto the torque converter have seperated.

Porsche put out a TSB about the rivets holding the two plates that make up the rear flexplate loosening over time and they start to chatter.

While you are back there also look into the torque tube at the rear pinch bolt to make sure it's still there and it is torqued correctly to 59 ft. lbs., or the new standard, 65 ft. lbs.

Other than those two areas, a thorough inspection overall to include a check for the correct amount of fluid in the tranny, checked with the 928 running and level.

Having a set of 928 WSMs would be very helpful.

HTH,

skippermccoy

I checked the TT through the inspection hole and it is tight looks new. The clamp and TT are painted grey and the allen bolt on the clamp has a red line on the head of the allen bolt onto the clamp. Will I be able to see if the flex plates are loose through the cage that NC928S4 suggested I look through for some rubbing. I f not is there a way I can check them? I will also drop the full exhaust tomorrow to check it front to back. I did check the exhaust welds in the back and they look great I will keep digging. Thanks all for the help. I do need a set of the 928 WSM

Mrmerlin

can you post more details about what type of trans you have?
what was the last thing you fixed?.
If its a 5 speed then draining the trans will tell if there are metal chunks in the oil.
.
Remove the rear pinch bolt and see if its loose,
and also if the input shaft is damaged,
and inspect the bolt shank.
If its an auto you can remove the inspection covers on the front of the bell housing and inspect the bolts that hold the TC to the flex plate.

skippermccoy

It is a 82 3 speed auto. I have checked the rear tt clamp to verify it was tight. Mine has an allen head bolt and I do not have the allen bits that are in a socket so couldnt check the torque. I couldnt break it loose with an allen wrench. Tomorrow I will get some bits. It does have a red calibration mark across the head and onto the clamp. It is still lined up. Where are the covers that I can remove to check the TC? It just appeared to be a cage area to look through almost like it was 1 piece.

Bill Ball

You can't see what Constantine is suggesting - loose flexplate - without dropping the TT and removing the TC cover.

But I don't know if this applies to your model year. Besides that causes a rattle. Yours sounds worse than that.

Black Sea RD

That you can see the rear pinch bolt and it seems tight is a good thing.

The rear flex plates can really only be checked thoroughly with the torque converter housing off. But you could try to rap on the flexplate with the plastic handle of a large screw driver through the holes around the torque converter housing that you access to remove the six bolts that secures the flexplate onto the torque converter. You might be able to replicate the sound some.

Looking at the TSB Bill posted, the loose rivet problem should not affect your model year but it sure sounds something like that.

Good luck,

Mrmerlin

looking at the TSB picture you can see a dot on the front of the TC housing (at approx. the 2 O clock position there is one at the 10 O clock position as well)
this is actually a rubber plug there are two of them remove the plug turn the driveshaft till you can see the TC to flex plate bolts and tighten the bolts there are 6 of them

Bill Ball

I suppose the noise could be a couple of loose flexplate bolts, and you can inspect for that through the rubber access plugs in the TC cover, as Stan notes. You'll need to rotate the crankshaft to get the TC oriented so you can see a flexplate arm. Each arm has two bolts and you will only be able to see one bolt at a time. It sure would help to have someone turning the crank (27mm socket needed) while you look through one of these ports.

If all of the bolts are off, the TC will not spin and the car will not move. I had an instance in a buddy's 928 with a few loose bolts and another with a broken flexplate arm and everything seemed perfectly fine except there was a rattle when you turned off the ignition as things came to a halt. Did you ever hear that noise before this much worse noise started?

We are all assuming the car will still move in gear and the TC is turning with the motor running. If not, then the flexplate has broken completely free of the TC.

It is possible the TC is broken internally, but I have never seen that. The noise recording you posted sounds pretty hideous. Does the car still move in gear?

skippermccoy

Yes it will still drive and shift out through all the gears. I am making my run to the tool store to get some hex bit sockets to break loose and torque the TT clamps. So here is what I have planned
1.remove inspection plugs check TC flexplate tap it with screw driver then spin it and check bolts
2.Loosen Loc tite and torque rear TT clamp
3.Drop full exhaust to check all the welds for leaks
4.Remove front inspection cover and check clamp,flexplate and end play
5.dodge this sudden TN snow storm

skippermccoy

Everything in the back end is tight. PO had all the inspection plugs already out I need to order some so I dont suck anything in there.Now i am moving onto the front end. I ordered a trans filter and gasket in case this doesnt help the problem. I can then check the fluid internal end of it. Plus it wont hurt to have those things on hand even if the trans is bad.

dcrasta

Is there any way you can get it in the air (lift or on jack stands) ? Safer on a lift. but basically, up in the air, start it and let it idle and figure out where the sound is. If its inside the torque tube or the rear bellhousing you will probably have to drop the unit to inspect.

Does the sound change with the rpm ?
Is it constant?
Is there a change in RPM that occurs with the sound (like a misfire or something).

I would check the front inspection after looking in the rear.

Good luck, the torque tube/trans issue is a bit challenging but we can do it!