Torque Converter Issues?

[Bross82]

I think I may have finally narrowed the noise down to being either the torque converter or the transmission. I checked the 3 bolts on the flexplate and they were all good (35ft-lbs according to the Haynes Manual). I also noticed the bolts on the starter were able to be tightened down more. But, I started it up with the dust cover off and it still makes the knock noise.... It definitely did seem louder with the cover off. But it was hard to pinpoint if it was specifically the torque converter or the tranny making the noise. Underneath the tranny and towards the driverside I though it seemed quieter. It seemed like it could have been louder next to the side of the transmission on the passenger side (near the circular shaped piece, is that the lockup part?). I tried the trick with the rubber hose to try and hear better, but I couldnt really tell any difference and could only get so close without the hose with the exhaust pipe there. It makes the noise now pretty much in any gear, but does not seem to make it when in neutral until I rev the engine.

Any ideas on which this could be and how to test? Also, does anyone know what is a good site to look at getting a new tranny or torque converter from?

Thanks,
matt

 

[70~K5]

It could be a cracked flexplate.

 

[Bross82]

from what i could see i didnt see any cracks....do you know how visible the cracks typically are?....can you only really see them when you remove the flexplate?

 

[diesel4me]

You might not see them..

The flexplates usually crack in the bolt circle that holds it to the crankshaft..sometimes difficult or impossible to see until the flexplate is removed,or the tranny is pulled back enough to see that far in...sometimes if you pry on it with a bar you can hear it "snap" when the cracked part flexes..or try a small mirror ,see if you can get a look see in there...

Or you can just keep driving and keep your AAA card and cell phone handy--eventually it will break off around all the bolts,and only the center will turn with the crank--and the rest will not,and neither will the torque converter....time to call AAA...

I've heard converters that sounded like they had BB's in them,or broken "vanes" inside that drove the owners nuts,but never left them stranded..they replaced them for sanity's sake mostly...they blamed repeated brakestands for the converter noises....

 

[dyeager535]

Does it make the noise *constantly* in gear, or only when the engine is first under load, like accelerating? That would be a very good sign the flexplate is cracked.

Only converter problems I've heard have been a grinding noise when it was NOT in gear.

 

[Bross82]

the last few times I started it over the weekend... the noise started and didnt go away. It is a constant knocking noise when idling when in any gear (except neutral). When I rev the engine, it picks up speed and then slows down. when it was in neutral, after reving, the noise would go away when the rpms went back down and the motor idled.

the weird thing is that it used to go away sometimes when in park a while ago, where the rpms are the highest when idling....so i'm not sure if it just happens more around a certain rpm range...or happened...now it happens in park too.

I'm not sure about how it sounds when there is more load on it such as while driving, it has been pretty much parked since the problem got a lot worse. the last time i actually drove it, it was making the noise while driving....

thanks for any help.

 

[mountain4x4]

Umm, hope it's not rod knock... How's youre oil pressure? Has it dropped at all?