Help With Crackling Noise

[BASS]

Ok, once the car/transmission is warmed up, when I step on the gas and let go, I get a very annoying CRACK-CRACK-CRACKling noise when I let off the gas after boosting. Also, I get this crackling noise directly after I rev up the motor after putting the tranny in neutral while I am cruising. I looked under the car and everything looks tight/normal. I also removed the converter cover and all the bolts are there and tight. The noise appears to be coming from directly underneath the car. It makes different amounts of this crackling noise at different times..


I also noticed that when I put the car into Drive, it shifts into drive abruptly sometimes. (Also, the vice versa--if I go from Drive to reverse or vice versa, it shifts into that gear rather abrubtly, but only sometimes)..


It appears to be something with the tranny, although it shifts perfectly. is it possible that something behind the pan is loose/disconnected??

How do you drain the tranny oil so I can remove the pan to see whats going on?? (theres no oil drain plug surprisingly!) This has been driving me nuts for the past few months..

 

[Topjimmy]

Sorry I can't help with the noise, you might try posting in the Transmission section.
A trans drain pan (cheap at most auto stores) will be your friend on this job. To remove the pan, loosen all the bolts but only remove every other one. With the remaining bolts screwed out and still attached, gently pry the pan away from the case. This will start the trans draining fluid without causing the big red lake. Slowly remove the remaining bolts as you lower the pan at one end to let out all the remaining fluid. Now is the perfect time to change the filter & gasket and clean out the pan. When you re-install the pan, snug the bolts up in a criss-cross pattern, no ape hanger torque needed here, let the new gasket make the seal. I recommend Dextron III ATF to refill.

Good Luck - Jimmy

 

[challengermike]

I dont know if this is your problem but have you checked your u joints?They can crack and pop if they are dry/ no grease.That would make sense when you would put it into gear and also when you are on and off the gas.The only thing that wouldnt make sense would be in neutral.The only other thing i could think of would be that your flexplate is cracked .They like to crack right around the bolt holes where is attaches to the crank.Its sometimes really hard to see unless you pull the tranny out.

 

[wile87]

you didn't mention if you could here any noise coming from the trans. while just idling. get under the car and listen to hear any rattling or what sounds like a very very light knocking type noise while idling and if you have someonr

that can . this could very well be a cracked fllywheel if you do here anything like that

 

[Electrajim]

Do you have a driveshaft loop? If so, be sure the driveshaft or the loop doesn't show any sign of contact with the driveshaft.

Just a thought.

ElectraJim

 

[BASS]

Ok, I still have that annoying crackling noise I took the converter cover off again and checked out the flexplate, and it looks fine. Also, the converter looks ok and all three bolts holding it on are secure.

Im really starting to think its something behind the tranny pan rattling around..Anyone have any clue what it might be? Maybe a magnet or something rolling around in there?? It must be something rather large and not a small washer or something to be making that big of a noise, especially since its rolling around in the fluid..

Ill be dropping the pan down soon..Does the dealer still sell the GM filter&tranny gaskets??

Any other special things I should look out for while changing the tranny fluid, or is it pretty straight forward? I know I should overfill it about a quart or so...

 

[BASS]

Ok, im thinking this crackling noise has something to do with the driveshaft. How do I make sure the U-joints are ok? I took a quick peek the other day and they looked ok by visual inspection..

I also notice that when I put the car in Park, I can roll the car about 1/2 foot, which leads me to believe it has something to do with the driveshaft

 

[BASS]

I think I found the problem! Attached, you can see that the driveshaft is barely rubbing against the exhaust Y pipe..So, it makes sense, any little vibration from the exhaust pipe makes that ting ting/crackling noise!

Now how am I gonna adjust the Y pipe? I need to get a new one anyways since mine developed a hole on the side where the cat converter hanger attaches to it..I also noticed that the passenger side of the muffler hangs lower than the driver side (and I checked all the hangers and they are all attached)..I think the metal slab piece thats attached in the rear section of the muffler system needs to be bent a little to adjust the muffler?? This is a 2 1/2" magnaflow system by the way...

 

[BASS]

I just realized, when I jacked up the car using the jack in the rear, the Y-pipe raised and touched the driveshaft..When I lowered the car back on the ground, there was plenty of clearance then..Oh well, im still stumped on this one..Im still thinking it has something to do with the U-joint or yoke..

 

[gusszgs]

Does this noise only happen when your in boost and let off quick?

 

[Phoneguy]

This can not be as simple as a "snort" ........... can it ?


Bryan

 

[BASS]

This is definitely not a snort. It makes random metalic clanking noises when I let off the gas either after boosting it or just lightly pressing on the gas and letting off (random). Its coming from the bottom and/or corner of the car, and not from the motor. When im going on the highway, it makes like a rapid machine gun noise when I let off the gas (like a rat-tat-tat-tat noise) for about a second or so... I took the converter cover off again and inspected the flywheel/torque converter and everything looks fine..Maybe its coming from the brakes, but I highly doubt it..

 

[Pronto]

How's your engine mounts? Check your downpipe to see if it's hitting the frame.

 

[87geeinn]

I couldn't tell from the pic if you are using a cat or a test pipe. I had a real sharp clacking/cracking/ticking sort of noise that was coming from the slip fit area where the downpipe slides into the front of the test pipe. It almost sounded as if the metal was cracking. Hey, it's an easy check and while you are at it, check all of the other exhaust components and where they have connections to each other.

My car didn't do this until the car warmed up. Then I could lay down by the passenger side and yank on the downpipe/test pipe connection with an oven mit and cause it to make the sound. It was one of those eureka moments where you kinda sit there and go, "Well, I'll be damned. It can't be that easy can it?"

 

[TurboBuRick]

Sounds like either a u-joint or something in the rear end. Definitely speed related. While you were under the car, did you grab the shaft by each u-joint and wiggle.:biggrin: You will know if its bad. If they are tight, I'd be pullin that dif cover.

Rick

 

[Pronto]

I couldn't tell from the pic if you are using a cat or a test pipe. I had a real sharp clacking/cracking/ticking sort of noise that was coming from the slip fit area where the downpipe slides into the front of the test pipe. It almost sounded as if the metal was cracking. Hey, it's an easy check and while you are at it, check all of the other exhaust components and where they have connections to each other.

My car didn't do this until the car warmed up. Then I could lay down by the passenger side and yank on the downpipe/test pipe connection with an oven mit and cause it to make the sound. It was one of those eureka moments where you kinda sit there and go, "Well, I'll be damned. It can't be that easy can it?"

If there is no clamp there that is very possible too.

 

[BASS]

Hmm, I bet its coming from where the test pipe slips over the end of the downpipe, as I have no clamp there (but, I thought your not supposed to use a clamp there )..I also noticed that my downpipe (Terry Houston) comes very very close to the flange of my stock crossover pipe, so I bet its vibrating on that flange too..

I double checked the U-joints/driveshaft and it looks ok (NO up or down movement, and I can twist it only about 1/4 inch, which I believe is normal)..

Anyone here with stock headers/crossover and a THDP can tell me how close the THDP comes to the crossover flange?

 

[Pronto]

I have a band clamp on my downpipe.

 

[Just a Six??]

I have a band clamp on my downpipe.

X2

 

[ChevMCarlo84]

I have a band clamp on my downpipe.

x3