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How does my exhaust smell
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Discussion Starter #1 (Edited)
I have a built tranny, with PI single disc 3800 stall that was installed about 6k miles ago. I have a rattling that sounds like it is coming from right in front of my tranny bellhousing, but definitely on the inside. The car revs and drives exactly the same as before except for this rattling sound below 2000 rpms. It sounds just like lightened flywheel chatter on a 6sp.

Anyway, before I have the tranny dropped and investigate, I was looking for educated guesses on what the noise could be. So far I have narrowed it down to

A) loose torque converter bolt (they all look fine on casual observation)
B) cracked flexplate (one of my tranny shop buddies said this would cause a noise like this.
C) loose bolt in the torque convertor (although I don't think this is
likely)
D) some problem with the crank (but I think that would cause drivability problems, which I don't have)

Anyone care to hazard a guess, or have experienced this before?
 

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Toyota MasterTech
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939 Posts
i just had the same noise about a week ago. it was three of the torque converter bolts that were loose. you probably know, but if not, there is a square rubber cover on the front of the tranny. if you pull it off you can get to the torque converter bolts easily one at a time.
 

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Premium Member
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11,271 Posts
I have seen the TC bolts and or flex plates bolts loosen up and cause this. Usually its on cars with a smaller pulley on the crank where the dampener has been removed.


Larry
SP
 

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Registered
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208 Posts
Sound Performance said:
I have seen the TC bolts and or flex plates bolts loosen up and cause this. Usually its on cars with a smaller pulley on the crank where the dampener has been removed.


Larry
SP

Thats exactly what happened to me. I also have a smaller pulley. Huh I never thought about the pulley helping cause this. I'll have to see if it happens again but my converter was just installed when this happened and they might not have been properly tightened.


John
 

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?!!?HABBA BABBA??!!
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2,757 Posts
bump up...has anyone else experienced this?? I am running a Boost Logic crank pulley on mine and mine is being CRAZY.
 

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a supra..fast..hahaha
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i'm having a similar noise but i thought it might be the exhaust rattling under the car cause it is a little loose.. could that be it rubbing on the undercarriage of the car or should i check the bolts on the TC? I don't have any aftermarket pulleys on my car either
 

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Enter The Supra
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I'm running a UR race pulley on my crank and no problems. I did put lock-tite on all of my torque and flex plate bolts though. There's a lot of discussion back and forth on this subject. First the Supra engines (I was told this by an experienced Toyota mechanic) are internally balanced, so the dampener is there to make certain nothing externally is out of balance, such as the pulley. I talked it over with a few people and for now I at least believe that the UR Race Pulley may be too light to actually do any damage. The are CNC'ed machined like the boost logic pulleys, but much lighter, I think they're actually less than a pound. All that being said, I don't see them being so far off in balancing that it can do any internal damage. I know I may get blasted for this and I've read posts where people have blamed engine failures on it, but after 6,000 miles on my car, I have seen no signs of any sort of damage due to it. Let alone anything happen to the rest of the drivetrain b/c of it.
 

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?!!?HABBA BABBA??!!
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well i looked in my access panel tonight on my tranny, and one of the 6 bolts ive inspected so far is broke in half!
 

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Enter The Supra
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well i looked in my access panel tonight on my tranny, and one of the 6 bolts ive inspected so far is broke in half!
I'm not trying to sound like someone in denial, but it's not necessarily due to your balancer. The BL you have is actually SFI approved. Here's a link that talks a bit about the Unorthodox Pulley I have. More importantly, the individual claims that the OEM balancer on the crank is not for actually balancing the rotating assembly, but to reduce accessory pulley noise, which is common among most new cars today. Again, I'm not trying to start a fight with anyone, but merely provide you with other info. I looked at as well on the balancer side of the engine.

http://www.supraforums.com/forum/showthread.php?t=147367&highlight=Unorthodox+Race+Crank+Pulley
 

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HighCompression+Boost=Win
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1,888 Posts
I'm not trying to sound like someone in denial, but it's not necessarily due to your balancer. The BL you have is actually SFI approved. Here's a link that talks a bit about the Unorthodox Pulley I have. More importantly, the individual claims that the OEM balancer on the crank is not for actually balancing the rotating assembly, but to reduce accessory pulley noise, which is common among most new cars today. Again, I'm not trying to start a fight with anyone, but merely provide you with other info. I looked at as well on the balancer side of the engine.

http://www.supraforums.com/forum/showthread.php?t=147367&highlight=Unorthodox+Race+Crank+Pulley
I am not saying you are wrong, but the same thing happened to my friend like 2 weeks after he replaced his OEM crank pulley with a one-piece aluminum one.
 

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Enter The Supra
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Really strange. I had my UR pulleys on there for about 5,000 miles and 5 months. Then I sawpped my tranny and torque and didn't see anything wrong with anything in there. I've put another 1,000 miles on it since and still nothing. All of the speculation does scare me, but my car is kind of the proof that there aren't any side effects. ... at least so far. I am curious to open up my shortblock and see if there are any signs of improper balancing, but that won't be for another year or 2.
 

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HighCompression+Boost=Win
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I think it is usually a combination of the crank pulley and some of the flex plate bolts not having enough/any thread lock on them.
 
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