Strange rattle from rear of engine Auto Transmission
02-19-2009, 09:32 PM
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Strange rattle from rear of engine Auto Transmission
I put the car up on a rack and listened to a strange rattle like sound that is coming from the housing attached to the rear of the engine on this auto transmission car. The seller said "oh it is just the catalytic converter that you can cut out or bypass and it goes away when it warms up". It is not the muffler or converter but inside the housing when in park and idling. Any thoughts? TIA
Walter Jones
1989 928s4 Auto Tranny
Walter Jones
1989 928s4 Auto Tranny
02-19-2009, 10:09 PM
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Hi Walter,
Drop the lower part of the housing by removing the 6 bolts and take a look at the front flexplate which is attached by six bolts to the flywheel. The drive shaft should be clamped in the front flexplate clamp and everything should be tight.
While there check for a forward bowing of the front flexplate by placing a small straight edge against the flexplate. If there is a bowing, this is bad and the front pinch bolt should be loosened to allow the flexplate to relax and go back onto the drive shaft by 2-6mm. Then pull the flywheel and flexplate back, toward the transmission, with a prybar and torque the pinch bolt again to 65 ft lbs using a torque wrench.
Sounds in and around the torque tube will travel up and down the tube. The above directions should at least get you on the way.
Let us know what you find,
Constantine
Drop the lower part of the housing by removing the 6 bolts and take a look at the front flexplate which is attached by six bolts to the flywheel. The drive shaft should be clamped in the front flexplate clamp and everything should be tight.
While there check for a forward bowing of the front flexplate by placing a small straight edge against the flexplate. If there is a bowing, this is bad and the front pinch bolt should be loosened to allow the flexplate to relax and go back onto the drive shaft by 2-6mm. Then pull the flywheel and flexplate back, toward the transmission, with a prybar and torque the pinch bolt again to 65 ft lbs using a torque wrench.
Sounds in and around the torque tube will travel up and down the tube. The above directions should at least get you on the way.
Let us know what you find,
Constantine
02-19-2009, 10:33 PM
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Check the rear flex plate and if it is attached by rivets thats your problem.
You will need to drill out the rivets and replace with bolts.
Search is your friend.
You will need to drill out the rivets and replace with bolts.
Search is your friend.
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
02-19-2009, 10:50 PM
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I read some of the archived posts and they seem to say that 87 was the last year for rivets. Is this correct as mine is an 89. Will pull off plate tomorrow and check. Thanks
Walter Jones
982S4
Walter Jones
982S4
02-19-2009, 11:09 PM
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I am fairly certian that on my 87 the rivets are loose. (didn't drill and replace when I had the tranny out 
) My rattle is coming loud and clear from the torque converter housing. Not the front flex plate area. And it is only present at idle.
Listen again and make sure its not coming from the converter area.
) My rattle is coming loud and clear from the torque converter housing. Not the front flex plate area. And it is only present at idle.Listen again and make sure its not coming from the converter area.
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02-20-2009, 06:32 AM
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Hi Walter,
Just for clarity, the rear flexplate is attached to the torque converter which is at the front of the transmission. Not easy to check with the trans in the car.
Good luck,
Constantine
Just for clarity, the rear flexplate is attached to the torque converter which is at the front of the transmission. Not easy to check with the trans in the car.
Good luck,
Constantine
02-20-2009, 09:50 AM
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We have found rivets on cars as late as 1990.
The 87 being the last was a myth.
Checking for the rivets in the car is pretty easy, fixing it will require you to drop the suspension a few inches and move the gearbox back to access the front of the TC.
The 87 being the last was a myth.
Checking for the rivets in the car is pretty easy, fixing it will require you to drop the suspension a few inches and move the gearbox back to access the front of the TC.
