Metal Clanking Sound, Coming from Starter or Tranny-Flywheel/Plate, what could it be?

[SG-MALiCE]

Well, as the subject says...

I have a clanking sound coming from my Fly-Wheel (Tranny), I suspect it's the Starter Motor somehow grinding on the Fly-Wheel, or at least thats what it sounds like. I've isolated the "Clanking" sound to the exact area where the Fly-wheel meets the Starter. Although thats where the sound is coming from, I can't be certain as to whether or not it's a transmission or starter related problem.

It only occurs when I crank the engine over (turn key etc), once the engine/car starts, it quiets down with a 'slight/faint' clank here and there, and then goes away entirely. The sound only returns when I shift from "D" (Drive) to "N" (Neutral) or "R" (Reverse) while driving. Then again, if I pull over and begin to turn the car off, it clanks a few times (or more) then shuts off.

Start car, same thing again. Clank Clank Clank, Chatter, Clank, Chatter... and then evens out, quiets.

The engine runs 100%, and idles beautifully.

The tranny shifts fine, no problems. I'm an ametuer when it comes to cars, but to my best judgement and gut-feeling, it's coming from either the "Fly-Wheel" or "Starter". At first, I thought a rock or piece of debris got stuck or lodged somewhere in the Fly-Wheel-Area and was clanking around while turning it over. Then once it's running, it stops. I have physically inspected the Fly-Wheel and Starter, there are no visible signs of wear & tear on the Fly-Wheel and while running, it's solid and even.

Well, I know thats not the best description of this problem. But perhaps some of you can enlighten me on this, and hopefully tell me it's my Starter and NOT my Tranny, for obvious reasons. =)

Any thoughts on what this could be, anyone?

Thanks.

[PAman]

Could be the flexplate has slipped on the crank and/or is lose.(this has the driven gear that mates w/starter and is the interface between the crankshaft and the torque converter...roughly equivalent to a flywheel) Cheap to buy the new parts, but the engine will have to pulled. I changed mine when I put another engine in it...and it showed signs of sippage at the crank. I understand GM has changed the crank bolt torque procedure to a torque-angle procedure for this reason. Difficult to diagnose without pulling the engine, but it will get worse. Possibly, the torque converter inspection cover can be removed and, with a flashlight, you may be able to see if the flexplate-to-crank bolts have loosened. While you're there, check the flexplate-to-torque converter bolts .

[SG-MALiCE]

Originally Posted by PAman

Could be the flexplate has slipped on the crank and/or is lose.(this has the driven gear that mates w/starter and is the interface between the crankshaft and the torque converter...roughly equivalent to a flywheel) Cheap to buy the new parts, but the engine will have to pulled. I changed mine when I put another engine in it...and it showed signs of sippage at the crank. I understand GM has changed the crank bolt torque procedure to a torque-angle procedure for this reason. Difficult to diagnose without pulling the engine, but it will get worse. Possibly, the torque converter inspection cover can be removed and, with a flashlight, you may be able to see if the flexplate-to-crank bolts have loosened. While you're there, check the flexplate-to-torque converter bolts .

Ok, I had my Starter pulled and tested today.

Starter is fine.

The clanking sound occurs when I manually shift (Reverse, etc) then it goes away once in gear. It also clanks fiercly when "Starting" the car, and "turning it off". I've narrowed this problem to the Flexplate (Flywheel), and that's definately it. As to what exactly is wrong with it, whether it be loose bolt(s) or assembly, I'm not sure.

All I know is the clanking sound is loud, and mind numbing.

I recently had this tranny rebuilt about 6 months ago (TH400), and hasn't had a problem until now. Obviously when they rebuilt the tranny, they used the old "Flexplate" and it's obviously worn out now, or damaged to the point where it's grinding/clanking. Now, assuming it is my flexplate... how long can I drive it like that before it becomes "un-drive-able"? Also, would it be cheaper for me to buy the flexplate myself and then pay someone to pull the tranny and replace it?

What would be the best course of action from this point assuming that's the problem?

[mjgjr72]

check if the torque converter bolts are tight the may have loosend up

[SG-MALiCE]

The other problem is, I don't have an easy place to work on my car. We live in a city with lots of hills, and I don't trust my "jack". So doing any work to my Park-Ave personally is out of the question. But is there a means to visually inspect this to see if something's not as it should be, without taking anything apart?

[SG-MALiCE]

It was a few "loose" bolts on the FlexPlate to Torque Converter!

lol...

[PAman]

Glad you found it. I was referring to a FWD Park Ave, but RWD has the same parts. I'd replace the bolts, and thread-lock them, if not already factory-applied.

[timrice]

Originally Posted by SG-MALiCE

It was a few "loose" bolts on the FlexPlate to Torque Converter!

lol...

How did you actually determine the bolts were loose? Can they be seen without opening up the torque converter, or was it all just external inspection?

I have a 3800 V6 in a LeSabre that makes a brief rattle when the torque converter engages or disengages, or so it seems. I thought about disconnecting the electrical power to the TC to see if the rattle stops or continues, just haven't tried it yet.

[aarcuda]

he is talking about the bolts that go thru the flex plate into the torque converter. you can access these bolts from under the car (behind a small plastic inspection shield). it at the juncture of the engine and tranny

[tman]

Paman- 1991 is a FWD car.

[PAman]

Wow, you mean I can get a TH400 for mine? (my '73 Z28 had one a' them) Didn't see any mention of a year, until the LeSabre dude got involved, Oh, that's right, I didn't see SG's profile.... Cut me a break!!!!!!!!!!!!!!!!!!!!!!!
PS: I had a 91 Ultra and it's still running around town. I know a little about these, having owned one (of two) for about 7 of the past 10 years. I've changed engines, shocks and many other parts....and both vehicles are still running....hmmm

[SG-MALiCE]

Well actually, I had no idea where the noise was coming from. Then someone recommended that I check the "Torque Converter Bolts" to see if they were loose. Since I had recently had the tranny rebuilt, I completely overlooked that, considering the amount of confidence I have in the shop that rebuilt my TH-400. I never thought that the bolts would be loose, but it can happen.

Once recommended that I check, I took my fingers and went under the car (cold), and rocked the Torque converter back and forth, as it rocked, the bolts rattled indicating they were extremely loose. That was the problem. So I immediately tightened them up, as tight as possible, and that solved the problem. The reason I could do that, is because many years ago via all the work that has been done to my beast, we removed the tranny heat-shielding panel (or whatever you call it), and now have direct access to that region of the tranny.

Just comes to show you, that even your mechanic, or the garages you take your car to, sometimes miss a thing or two. It's always good to know as much about your car as possible, then you can double check their work.

[the_doctor]

Originally Posted by SG-MALiCE

Well, as the subject says...

I have a clanking sound coming from my Fly-Wheel (Tranny), I suspect it's the Starter Motor somehow grinding on the Fly-Wheel, or at least thats what it sounds like. I've isolated the "Clanking" sound to the exact area where the Fly-wheel meets the Starter. Although thats where the sound is coming from, I can't be certain as to whether or not it's a transmission or starter related problem.

It only occurs when I crank the engine over (turn key etc), once the engine/car starts, it quiets down with a 'slight/faint' clank here and there, and then goes away entirely. The sound only returns when I shift from "D" (Drive) to "N" (Neutral) or "R" (Reverse) while driving. Then again, if I pull over and begin to turn the car off, it clanks a few times (or more) then shuts off.

Start car, same thing again. Clank Clank Clank, Chatter, Clank, Chatter... and then evens out, quiets.

The engine runs 100%, and idles beautifully.

I have the EXACT same problem with my 1989 LeSabre! SG described my problem exactly. I noticed SG-MALiCE has a 1979. I’m hoping I can fix the problem the same way on my 1989. Are these bolts easily accessible on a 1989 3600 V6??

Thanks,
Matt

[HotZ28]

Don,t just tighten the bolts, remove them and put loctite on the threads, then install and tighten!!! That is what your tramission shop failed to do.

[the_doctor]

Thanks. I'll definitely put loctite on the threads.
So I really can access these bolts without taking anything apart?
Are they easy to get too?
How many of them are there?
Will anything fall apart or leak if I remove them to loctite them?
Thanks!