Hello,

Upon acceleration my 91 240 makes a substantial "tinny" sort of thin metallic clatter sound. If I let up on the throttle the sound mostly goes away. I initially thought it was loose exhaust bits, but after removing the thin exhaust shrouds from the header pipe and the preheat hose area the sound remains. I even replaced part of the exhaust. It is coming from the torque converter area. No other symptoms, doesn't make any sounds at idle, and has made the sound in neutral, park, and drive - all I need to do is press on the throttle - both stationary and moving. However, sometimes in park or neutral it will not make the sound (a bit inconsistent). I looked at the flex plate and the bolts are tight / no metal cracks. Fluid level is correct. Car drives fine for the time being, even on the highway.

Any ideas? My plan is to at least prepare by learning where to get a torque converter and which one I need to get.

Does anyone that has done this already know where I can buy a torque converter for the AW-70 online, and which specific one (so far there seems to be a few different types, bolt patterns, etc.)? I don't plan on visiting a pick 'n pull, I'd just like to order one online and have it here ready to go.

Thanks, Joe
91 240 (California, with EGR)
AW-70 (non lockup)

it is quite possible your cat has broken up internally and the pieces are rattling against the outer walls

I'll check the cat with a stethoscope, or maybe by placing a small audio recorder under the car while driving. I haven't lost power or MPGs yet, but I sure hope it is the cat - it appears to be the oldest part of the exhaust system and replacing it would be preferred over any of the other options.

The cats with loose stuff in them respond very clearly to a tap with a rubber mallet.


--
Art Benstein near Baltimore

You spend the first two years of their life teaching them to walk and talk. Then you spend the next sixteen telling them to sit down and shut up.

What part of the exhaust did you replace?

Is there any chance it could be the heat shield on the catalytic converter?

Probably you would have noticed but sometimes things are hiding in plain sight.


--
'80 DL 2 door, '89 DL Wagon

How many miles, please?

And the transmission fluid is a bright, pink color, clear? How long since your replaced or performed the transmission fluid flush. That AW-70 specifies the GM Dexron III. While GM no longer support the spec, you can find quality Dexron III fluid. Some will flush with dino Dexron III, then go to a synthetic like Mobile 1 Dexron III or some such.

This board is rife with such information. Please try the search feature and use Google to target www.brickboard.com/RWD/

The transmission fluid does not smell strongly of phenolic like burning PC or circuit board, hot brake on a large over the road tracker trailer after it descends a steep grade, and the like.

While your fluid may be clean, if the filter screen, accessible by dropping the transmission oil sump pan, and checking for chunks of friction disk. In spite of the screen, these chunk may be small enough to futz with the overdrive solenoid valve body. When dropping the pan on these AW series, please employ great care when separating the transmission dip stick tube from the pan.

Same care required should you need to remove the transmission lines to the transmission fluid cooling portion of your radiator.

Though not sounding like a failing U-Joint, have to twist tested all three U-joints. And you know of the bright buzzing, hissing, whining sound of a failing drive shaft center support bearing? Best heard at about 25-45 MPH, with passenger windows down, with a high curb paralleling your track. The curb does nicely to reflect the sound back into the passenger compartment.

If coming from your non lockup AW-70, see issues with a clogged screen filter in the 700-900-90 FAQ:

https://www.brickboard.com/FAQ/700-900/TransmissionAuto.htm

And see:

https://www.brickboard.com/RWD/index.htm?id=718253&show_all=1

http://forums.turbobricks.com/showthread.php?t=288068

http://www.nuceng.ca/bill/volvo/database/tranny.htm

https://www.brickboard.com/RWD/index.htm?id=718253&show_all=1

http://www.volvo-forums.com/t19734-aw-70-transmission-servicing.htm

If a failing transmission, you can find replacement such as upgrade to the AW-71. These transmision are found on other cars, like Toyota, I guess.

Again, how many miles. With care, these transmissions can last for quite some time.

Though most people that purchase RWD Volvo autos neglect the crap out of them, believing these RWD Volvos are nearly invulnerable, and that just ain't true.

RWD Volvos are nearly invulnerable, with care, and love, and you drive them. A RWD Volvo dies if left to sit, unless you mean to properly store it.

Though other brickboard members here are vastly more qualified to answer your question than I with respect to the AW-xx series.

I'll fix, 'em ...

Questions?

Hope that helps.

Manual M47 II Transmission Boyeeeeeeeeeeeeeeeeeeeeeeeeeeeee on my RWD Volvo.
--
The Volvo 164: The Mightiest of All Volvo Automobiles in Perpetuity

Thank you for the replies.

It has 148,000 miles on it. When I bought it last November the transmission fluid was in good condition and had been flushed and changed within 5,000 miles, but, was overfilled by a quart. I also began to notice an intermittent hum on the transmission lines, which happens on my other 240 with an auto transmission, but this one was extra loud. Worrying about a clogged or loose filter screen I went ahead and dropped the pan to check the screen and it was like new. Since I was there I went ahead and replaced the filter screen and refilled the transmission with Maxlife DEX/MERC to the correct level - that was about 2000 miles ago. The fluid is still bright red and doesn't smell.

Possibly it has a cracked flex plate near the center, only apparent when the transmission is removed. YouTube videos about cracked flex plates seem to have a similar sound as my car.

My options, as far as I see it:
- do nothing now and drive it until something breaks to the point where it doesn't move, then fix it (the real problem might be more obvious then)
- drop the transmission and look at the flex plate, if no cracks in it replace the torque converter at that point

Any ideas? Thanks, Joe

I believe you can go to www.advanceautoparts.com and get the standard Dacco reman torque converter. The best part being that you can use their online coupon codes and get up to 20% off typically.

I have a similar problem: a metallic hissing when the transmission is torqued by the throttle. Let off the throttle and the car coasts silently. I have contemplated swapping the torque converter, but the last time I separated the transmission, it was so much fun I vowed not to do so again unless I was going to be certain of fixing the problem. I am not 100% sure the pump isn't the problem, nor am I sure the clutch packs haven't suffered any overheating or wear from slipping due to the torque converter issue.

Please let us know how it turns out.