Unknown noise problem..help please

[DmaxHawk]

Not really sure where to post this..

Alright it started this afternoon, I went to check a bridge we are building. When I got there I put it in park and let it cool down a bit. I noticed a slight unusual vibration on the driverside but wrote it off to the tractor working there. when I got back into the truck I noticed it again, I stopped and let it idle while I stepped outside. it kinda sounded like the exhaust manifold had a leak or something similar. on the way home everything was normal, boost egt, temps, no white smoke, everything checked out. it goes away when I give it a bit of throttle. it only is noticeable when it idles. I got it up on my lift and it seems like its coming from the torque converter. It sounds like its coming right from the bell housing. ???. oil levels are normal. It still pulls hard and the tc locks like normal ill try to get a video or audio clip to you guys soon. The best sounds I can compare it to is an impact wrench only a bit quieter.. in park the speedo jumps, sometimes up and down up to 10mph. im currently at the shop typing this on my phone and can't search so sorry if this is a repost. any help would be appreciated. thanks

 

[BIG DIPPER]

Flexplate....check the bolts.

Speedo jumping while reving has been common....not all, but a lot. My 02 would do it.

 

[super diesel]

Cracked flex plate? Remove the rectangular inspection plate and start it up. Look inside to see if the T/C is moving any. If not, it still maybe broke. If it gets worse with time (short time) it may only be broke around the mounting holes that hold it to the motor. Hopfully this isn't the problem though.

 

[LBZ]

Another member here had the exact same complaint with the same symptoms turned out to be a flexplate. His exact quote was "....sounds like and exhaust manifold leak......." and "......goes away with increased rpm......."

 

[super diesel]

I've wasted 2 in the past. Just recently help a friend with another. Same symptoms.

 

[DmaxHawk]

Flexplate....check the bolts.

Speedo jumping while reving has been common....not all, but a lot. My 02 would do it.

Thats the problem, its jumping at IDLE, i noticed that it did jump while revving but now it does it at idle.

Cracked flex plate? Remove the rectangular inspection plate and start it up. Look inside to see if the T/C is moving any. If not, it still maybe broke. If it gets worse with time (short time) it may only be broke around the mounting holes that hold it to the motor. Hopfully this isn't the problem though.

Ill check that inspection plate. How many horses is the stock flexplate good for? Would it break with my mods? Kinda hoping it is the flex plate and not something more serious. Plus it gives me an excuse to fix it with something stronger

Another member here had the exact same complaint with the same symptoms turned out to be a flexplate. His exact quote was "....sounds like and exhaust manifold leak......." and "......goes away with increased rpm......."

What was wrong with his? where was it broken?

 

[Gasuout]

Cracked flex plates have been very common , especially with a ATS converter . Ive cracked 2 .

Mine sounded funny at each shift light throttle . You could hear a tinny sheet metal sound just as it shifted . Both cracked differently but sounded similar .

I didnt hear anything or feel vibration at idle though .

Maybe you have loose bolts or are missing a few .

Good luck , hope you figure it out .

Johnny

 

[DmaxHawk]

Cracked flex plates have been very common , especially with a ATS converter . Ive cracked 2 .

Mine sounded funny at each shift light throttle . You could hear a tinny sheet metal sound just as it shifted . Both cracked differently but sounded similar .

I didnt hear anything or feel vibration at idle though .

Maybe you have loose bolts or are missing a few .

Good luck , hope you figure it out .

Johnny

I'm going to take it to an Allison shop here soon, see what turns up. Thanks

 

[Mike L.]

I'm going to take it to an Allison shop here soon, see what turns up. Thanks

Make sure they know the TQ procedure as it is critical.
58 ft lb, then 60 deg, then another 60 deg.

 

[super diesel]

Mine also broke with the ATS T/C. No problems with the suncoast I'm running now. However, The one I just assisted with was behind a suncoast T/C. UH OH! Torqueing? OOPPS!

Sal. Your's sould be fine for a while with replacement. The mods you have are fine with the stocker. I've always run a stocker, and some here remember what I use to do to my poor flexplates years ago (UHH and still). I don't think I remember Pat killing one. Please correct me on this Pat, Kat or Mike L. if I'm wrong.:hug:

 

[DmaxHawk]

Make sure they know the TQ procedure as it is critical.
58 ft lb, then 60 deg, then another 60 deg.

Mike can you explain the "60 deg" part to me please. Thanks

Mine also broke with the ATS T/C. No problems with the suncoast I'm running now. However, The one I just assisted with was behind a suncoast T/C. UH OH! Torqueing? OOPPS!

Sal. Your's sould be fine for a while with replacement. The mods you have are fine with the stocker. I've always run a stocker, and some here remember what I use to do to my poor flexplates years ago (UHH and still). I don't think I remember Pat killing one. Please correct me on this Pat, Kat or Mike L. if I'm wrong.:hug:

Why does it seem like they break more with the ATS t/c's?

 

[Mike L.]

Mike can you explain the "60 deg" part to me please. Thanks



Why does it seem like they break more with the ATS t/c's?

The flywheel bolts are strech to fit which means the bolts are stretched at a certain tq and that assures that they will not loosen under the vibrations of the diesel engine. It is not easy doing this. Tq multiplier would come in handy for this job.

 

[ripmf666]

That or 400+ lbs and long bar lol

 

[Turbo Buick 6]

That or 400+ lbs and long bar lol

:rofl:

 

[SmokeShow]

so you torque them to 58 ft-lbs then go 60* past that and then another 60* past that = 120* past 58 ft-lbs?????


c-ya

 

[DmaxHawk]

Cracked flex plate? Remove the rectangular inspection plate and start it up. Look inside to see if the T/C is moving any. If not, it still maybe broke. If it gets worse with time (short time) it may only be broke around the mounting holes that hold it to the motor. Hopfully this isn't the problem though.

I removed that inspection plate, all i could see is that the t/c spins.

 

[tobyk321]

Not really sure where to post this..

Alright it started this afternoon, I went to check a bridge we are building. When I got there I put it in park and let it cool down a bit. I noticed a slight unusual vibration on the driverside but wrote it off to the tractor working there. when I got back into the truck I noticed it again, I stopped and let it idle while I stepped outside. it kinda sounded like the exhaust manifold had a leak or something similar. on the way home everything was normal, boost egt, temps, no white smoke, everything checked out. it goes away when I give it a bit of throttle. it only is noticeable when it idles. I got it up on my lift and it seems like its coming from the torque converter. It sounds like its coming right from the bell housing. ???. oil levels are normal. It still pulls hard and the tc locks like normal ill try to get a video or audio clip to you guys soon. The best sounds I can compare it to is an impact wrench only a bit quieter.. in park the speedo jumps, sometimes up and down up to 10mph. im currently at the shop typing this on my phone and can't search so sorry if this is a repost. any help would be appreciated. thanks

i hate to say this, but it sounds exactly like how my truck sounded when my flex-plate was broke i hope you don't have this problem.

 

[DmaxHawk]

i hate to say this, but it sounds exactly like how my truck sounded when my flex-plate was broke i hope you don't have this problem.

Well if it is broken, it only gives me an excuse to make it stronger

 

[tobyk321]

so any updates on this? :angel:

 

[coldLBZ]

Sal, did your flexplate turn out to be broken or cracked?