What the hell is this noise?

SandShots · July 5, 2006

Allright guys. I think it might be the tranny.

This happens under highway speeds only. Once I let go of the gas and it coasts for about 8 seconds or more this loud clanking noise sounds from what appears the front of the transmission maybe the back of the engine but for sure it sounds right behind the dashboard. The noise goes away a bit at a time if I start to slow down and goes completely away once i get back on the gas. This happens even more often when im going downhill or pulling my small trailer, maybe because of the extra weight? Can a torque converter make this type of noise?

By the way the shifting and performance of the tranny does not seem to be affected by this, everything else is smooth.

Im taking my truck in for service tomorrow its still under warranty.

Tranny Geniouses, chime in and give me your thoughts. thanks guys.

05 HD 1500 Silverado Crewcab 4dr

4x4, 6.0L, 4.10gears, 4speed tranny?

14,000 miles.

OnyxMAX · July 5, 2006

I'm gonna lean tward cracked flex plate,but could lean U-joint if it clancs when you shift to reverse, or their is a vibration associated with it.

SandShots · July 6, 2006

I'm gonna lean tward cracked flex plate,but could lean U-joint if it clancs when you shift to reverse, or their is a vibration associated with it.

<{POST_SNAPBACK}>

theres no vibration and I doubt it would be a Ujoint.

Im not familiar with flex plate. what is that?

July 6, 2006

I'm gonna lean tward cracked flex plate,but could lean U-joint if it clancs when you shift to reverse, or their is a vibration associated with it.

<{POST_SNAPBACK}>

theres no vibration and I doubt it would be a Ujoint.

Im not familiar with flex plate. what is that?

<{POST_SNAPBACK}>

The flex plate is what your starter engages to turn your engine over. It's bolted to the crankshaft and torque converter.

http://www.carcare.org/Auto_Transmission/f...flexplate.shtml

SandShots · July 6, 2006

I'm gonna lean tward cracked flex plate,but could lean U-joint if it clancs when you shift to reverse, or their is a vibration associated with it.

<{POST_SNAPBACK}>

theres no vibration and I doubt it would be a Ujoint.

Im not familiar with flex plate. what is that?

<{POST_SNAPBACK}>

The flex plate is what your starter engages to turn your engine over. It's bolted to the crankshaft and torque converter.

http://www.carcare.org/Auto_Transmission/f...flexplate.shtml

<{POST_SNAPBACK}>

got it. i use the term flywheel. anyways, could the flex plate cause this noise?

SandShots · August 2, 2006

ttt

still having this problem. i took it to the dealer and didnt find nothing wrong with it. i dont even think they test drove it,

man its getting frustrating.

ken1mod · August 2, 2006

check the torque converter to flex plate bolts. I have heard of this before. the flex plate is the coupling between the crank and converter. if the bolts loosen, the noise is unbelievable.

Ken

SandShots · September 1, 2006

everyone was wrong. it wasnt the tranny or engine it was the transfer case. I finally got pissed off enough that I took it to a diffrent dealership.

Apparently these transfer cases are always turning even when in 2wd. the problem on deceleration is that something is broken inside causing this weird noise that keeps getting louder. its been at the dealer since monday and will probably will stay there another 7 days. GM does not have any transfer cases in stock. this is just crazy.

asilverblazer · September 1, 2006

At least it's under warranty, sometimes it takes a fresh set of eyes to find a problem. At least it is being taken care of.

crazymjb · September 1, 2006

This transfer case setup is confusing to me, now that you mention it. There appears to be a Solenoid(I have the electronic controls) on both my transfer case and front differential. I assume the one on the transfer case is just for the High/Low planetary gearset, and the one on the diff is for locking it to the input shaft... Am I correct?

Mike

jmassi · September 1, 2006

Sounds 'bout right.

OnyxMAX · September 2, 2006

i was in the right area

been a while since i messed with a gm front axel. they have done everything from vac lines in the hubs to a thing that heated up to lock the axel in.

crazymjb · September 2, 2006

When we did my axle seals the 4WD had to be engaged... Is it a solenoid that locks it in place or it actually uses heat to, say, bend some bymatalic strip or something? I noticed it got very hot to the touch(enough that you wouldnt want to hold on).

Mike