Vehicle:
1991 Formula 350 - A4
114k Miles
(Stock)

Problem:
At idle the transmission seems to make a marbles-brushing noise. In motion around 45mph the sound is unnoticeable. When accelerating hard, the car acts as if it were towing a heavy load. During normal acceleration, the vehicle gets up to speed fine.

References:
https://www.thirdgen.org/techbb2/sho...hreadid=103803
https://www.thirdgen.org/techbb2/sho...threadid=25707

Details:
Okay, so I did my homework and found the threads above. From reading it sounds like I either have a cracked flexplate, loose bolts, missing fins on the torque-converter or all of the above. Actually missing some fins sounds the most logical because the trouble it has when I floor the accelerator.

Last weekend I was at the airport and noticed a brushing/marbles against metal sort of noise echoing off the parking-garage walls. I just thought something was loose and scraping the drivetrain somewhere. At the time I could only hear it moving at those low speeds in the garage.

So I come back from my trip 3 days later, start up my car, and the noise is ten times worse and now when idling. I've got to get home so I baby it for about 2 miles. When I get on the highway I'm still taking it easy bringing it up to 70mph. I stayed at that speed for about 5-6 miles.

By the time I get to my exit the sound is almost unnoticeable. At the least, it's the volume it was 3 days prior. I'm still listening for awhile and don't hear anything so I decide to punch it at a light.

I was expecting to be thrown back into my seat but I wasn't. It took about 2~3 seconds for the RPMS to get up to ~4500. As the higher the RPMS became the slower it took for them to get higher. The general sensation was as if I were towing a heavy load. Even when the RPMS did get up to 4500, my speed was only 25mph, it never shifted.

So obviously all of that's not right and It's been parked all week. I did start it up a couple of days ago to listen. Same problems so I didn't drive it. I did rev. it a few times and kept it at 3k for about 10 seconds. I let idle for about 10 sec. and revved at 3k again for about 10 sec.

Well, after doing that about 3 times I noticed a peculiar smell. Almost as if something was burning, an oily-rubbery type of smell. It was not very strong at all, just enough to know it was there. I look at the water temp and it was just fine. I pretty much concluded the smell was from the transmission fluid overheating.

In Conclusion:
I don't deal with automatic transmissions much but I know the basic mechanics. What it sounds like to me is the converter is missing some fins and possibly I have a cracked flex-plate. Unfortunately I don't have the equipment to just open it up and find out.

What doesn't make sense is why sitting in a parking garage for 3 days would have been a catalyst for this problem.

If anyone has any ideas, I would be much obliged if you could help.

Thanks.

 

I got the same problem that you do i think, mine does it in park, nutral, accelerating, but not at crusing speed, just the noise not the smell, my tranny fluid is fine no smell or discoloration or anything, but that dern noise is driveing me nuts.

 

Besides the noise, are you having the same acceleration issue as me though?

 

not sure, i just droped that engine in and it has tons more acceleration than the six I took out but it has been doing it since it first fired so I have no comparison, if my acceleration is lacking I cant wait to see when it aint.

 

I had the exact same problem, except I lost converter lockup as well. It turns out that the flexplate was cracked very badly. I was dumb and drove it until the center of the flexplate actually separated from the outer ring! The converter had also lost some fins, like yours, and the lockup clutch was history. $120 for a nice used converter and a used flexplate and I was back in business. I am almost certain you have the same problem that I just fixed.