NC928S4

For many months I have had this clicking/ratcheting noise that occurs when I turn the car off or less frequently when it is in neutral or idling without moving in reverse or drive. I did a visual inspection of the flex plate at the Torque Converter inspection hole and also tightened the 6 bolts. No cracks were obvious and nothing was loose. A rebuilt TT was installed about 9 months ago and the noise existed prior but to a lessor extent. I would say the noise has been progressively getting more frequent but not louder.

I have no idea what is inside a Torque Converter but the noise is definitely coming from the TC.

All ideas welcome. Attached is a recording that depicts the noise. It happens every time the car is turned off. Upon startup you can hear the noise randomly occurring. It seems to be more prominent when warmed up. It finishes with the noise again when being turned off.

The Noise

jeff spahn

Could it be the flexplate at the rear? I thought 89 was one of the years with the bolt issue on the rear flexplate?

Ed Scherer

Here you go (it seems you had problems getting the video embedded).

jeff spahn

Man that sounds like my exploded rear bearing but you said you have a new rebuilt TT so rule that out.

NC928S4

Thanks Ed! I was just looking at what I hosed up on the link.

Bill Ball

Ed:

George Suennen had a rattle like that that only happened on startup and shut down, and in his case it was a flexplate with a cracked arm. His was the front flexplate. If you are sure it is in the TC area, then, at the least, the TC cover needs to come off. It could be the TC bearings or the inner bolts that hold the flexplate to the hub as well.

NC928S4

Thanks Bill. Is there anything inside the TC that could be causing this noise?

Looks like I'll be dropping the exhaust system, rear suspension and transmission again. Jeez tell me again why I love this car so much...

Bill Ball

I suppose there could be a broken vane inside the TC rattling around. I'm just supposing. I wouldn't know if it's a realistic possibility. But if you are going to drop the tranny then you should be able to pull the TC out and shake it.

GregBBRD

Loose counterweight inside the torque tube?

I took a torque tube out of an '89, this week, that had the counterweight so loose that it was rubbing on the torque tube shaft.

NC928S4

Thanks Greg for input. The TT was a rebuilt from our best supplier and the noise did exist before the TT replacement. Prior to the TT swap the dampener was sliding for and aft for since I picked up the car(20 months) but being a newbie and a long list of other stuff that needed attention I ignored the clanking back and forth noise.

My current theory is that the sliding hammer action of the dampener in the TT caused the tranny flex plate welds to fatigue and fail. I'm inspecting the fly wheel flex plate tomorrow morning to make sure I'm not hearing a reflective noise at tranny. Under the car the noise sure sounds like it is in the TC area but I have been wrong many times before.

Unless something is obviously hosed at the fly wheel area the whole shabang is coming out at Uncle Ray's shop on Thursday. When I did the TT swap I don't recall if I replaced the carrier bearings.

GregBBRD

While certainly anything mechanical can fail....from what I've experienced, torque convertor failures are rare.

Jherriott

Since the TC is full of fluid, I doubt that frequency of sound is emanating from within the TC itself. Just my hunch tho.

NC928S4

After removing the tranny and examining the rear flex plate and bearings nothing obvious was found.

Since everything was apart I replaced the TC/Flexplate bearings just because I didn't when I replaced the TT. Also put on 4 new axle boots with fresh grease. Highway driving is noticeably quieter.

The frickin random rattle/noise is still there - unchanged. I'll keep listening with my stethoscope hoping to find the root cause.

But basically, I'm just going to drive the **** out her until the noise evolves into a definitive failure.