Another engine noise post

[carter262]

Fixed: Another engine noise post

So I figured I would run this by y'all.

I have notice a change in the noise my M1009 make when driving. Like everyone else you get used to the sounds of your vehicle. Well a few days ago I noticed that mine started getting louder when driving. Prior the regular driving sound was tolerable but now it is a lot louder.

The sound seems to be worse when you are maintaining your speed. When accelerating or decelerating it quiets down some. It is OK when idling.

I just changed oil and filter. Change them regular. I run 2 cycle (17oz) every fill up. Tranny is APPROX 1 year old and brand new not rebuilt. I got lucky one that find. Fluid is good.

I have been reading on here and have found similar post but they seem to happen when accelerating not maintaining speed.

Any ideas?

 

[dmetalmiki]

Are you sure the "noise" is coming from the engine? as when the heat builds up the transmissions and shafts can start to whine or worse on steady throttle. If the engine is (more) noisy on slack running with no load on bearings etc, then (hopefully not!) that might be pointing to exessive wear there. What is the oil pressure like at that point? as compared to before. (you noticed the problem).

 

[richingalveston]

I have noticed that my truck will get slightly louder as the air filter gets dirty. Somehow the restricted airflow makes the low pitch drone of the engine louder. It is not a huge difference, just enough to notice.

 

[Skinny]

I would say drain the oil and send it for analysis or disconnect the torque converter to see if the noise is engine or trans related. This would be an alternative to running it up and disconnecting injectors to isolate the noise to a specific cylinder or pulling covers in hopes of seeing some type of accelerated wear.

 

[Warthog]

Have you checked for holes in the exhaust?

Also make sure the throttle cable is secure on the air breather. It can vibrate and cause a noise that is hard to find.

 

[Hasdrubal]

Hole in one of the exhaust pipes or muffler? Cold start solenoid staying on?

 

[cucvrus]

I want to throw my hat in. Have you checked the torque converter bolts? They are not to be reused they are to be replaced. They have lock tight built into the threads and they are also supposed to be torqued. I have heard and seen this noise several times and it was torque converter bolts. I am guessing so don't take my word as carved in stone. I wanted to put my hat in the ring. Let me know how you make out. I hope that helps. Good Luck.

 

[cucvrus]

These are new M10 torque converter bolts. I never reuse these. They are to inexpensive to take the chance with. I use the same rule on starter bolts. Use them once and throw them in the recycle bin. Do what you want. That is the way I was taught at GM school.

 

[carter262]

Thanks for the replies. To answer some of your questions and tell you what I have found so far.

Skinny: "I would say drain the oil and send it for analysis or disconnect the torque converter to see if the noise is engine or trans related."
I just changed to oil and filter so they are new and fresh. If I did drain it where do I sent it and what am I looking for in the results?

Warthog: "Have you checked for holes in the exhaust?"
I have looked and can not find any holes or cracks. It also doesn't sound like a leak. I could be wrong though. And wouldn't a leak get louder with more throttle? I did check the throttle cable, do to reading your suggestion in another post, and it is secure and ok.

Hasdurbal: "Cold start solenoid staying on?" I removed the green wire and it made no difference. When I start it the cold start solenoid kicks in and then kicks off like normal at operating temperatures.

cucvrus: "Have you checked the torque converter bolts?" No I have not.

I was able to climb on, around, and under today when the rain finally stopped. The sound diffidently sounds like it is coming from the plate with the six bolt between the tranny and the engine. That is where I hear it the loudest and the sound is getting worse.

I am leanning toward the flex plate or like cucvrus said torque converter bolts. I have the TM out now and am trying to figure out how to check these things without dropping the tranny.

If anyone has to know how and would like to give me some tips please do. Liek how to or where in the TM to look.
Also if you have any other ideas please keep them coming. This is my daily and only driver and I want to keep her running for a long time.

Also just to let you know. I do change the oil and filter regular. I religiously run it in park to warm up before driving. I check all fluids at least once a month. In a nut shell I take very good care of her and do not abuse her.

Thanks y'all

 

[Skinny]

Fairly common failure for the flexplate to crack or like mentioned above, the torque converter bolts loosening up. Could also have been improper installation from a previous repair. Either way, just pull the inspection cover and take a look up in there. You may need to find someone with an inspection scope so you can look around the bolts where the flexplate meets the crankshaft. Typically a cracked flexplate will get worse under load so if you stall test the transmission which is really like a burnout minus the tire spin (like a 6.2 with 3.08 gears can peel tires), the noise will get worse as you load the converter up.

I'm down in Wilmington area if you are nearby.

 

[carter262]

Fairly common failure for the flexplate to crack or like mentioned above, the torque converter bolts loosening up. Could also have been improper installation from a previous repair. Either way, just pull the inspection cover and take a look up in there. You may need to find someone with an inspection scope so you can look around the bolts where the flexplate meets the crankshaft. Typically a cracked flexplate will get worse under load so if you stall test the transmission which is really like a burnout minus the tire spin (like a 6.2 with 3.08 gears can peel tires), the noise will get worse as you load the converter up.

I'm down in Wilmington area if you are nearby.

Thanks I plan on checking it tomorrow. I'm in Greensboro about 3 1/2 hours away

 

[FMJ]

I know you changed the oil, did you check the level after you fired it up?

I just put a rebuilt motor in a CUCV and filled it to the full level on the dipstick, a week later I was trying to figure out why it sounded so rattlely, I was 1 and a half quarts low on the dipstick.

 

[the skull]

Mine was pretty noisy at idle, but as soon as it was off idle it was (quiet?)
(not as loud?) After closer inspection, there were 2 loose bolts in the
power steering pump bracket. Fixed quickly. All better. Then the pump
itself fell off the bracket, 1 bolt broke off, 2 were missing entirely.
It might be worth checking. It's also your brake booster.
Just saying.

 

[cucvrus]

Good point Skull. Don't throw that broken bracket away. Get it welded. They are getting hard to find. I even have mine numbered for the end of days. I think if he is hearing it from the bottom transmission cover it is in the torque converter bolts. I lean that way because that is normally what I find. Like I said just replace the bolts or put lock tight on them if you don't have or can't find new bolts. Center crack in the flywheel is not as common as the loose bolts in my experience. I have a triuck that has a hole in the transmission bell from the flywheel coming apart and shattering. Good Luck carter. You need a 15mm socket and a 5/8" wrench if the lines are attached at the bottom like they are supposed to be. Have at it and report the findings. Good Luck I hope it works out for you. Don't pull the transmission.

 

[Hasdrubal]

Iit sounded so rattlely, I was 1 and a half quarts low on the dipstick.

When I first got the M1009, before I knew it burned oil, it ran low on oil. Probably was 1 and a half quarts..or more. It got to the point where coming to a stop downhill on a slope the low oil level light flashed. The engine never sounded any different. I'm puzzled as to how yours "sounded so rattlely". Did you drive with the low oil light on?

 

[carter262]

I know you changed the oil, did you check the level after you fired it up?

I just put a rebuilt motor in a CUCV and filled it to the full level on the dipstick, a week later I was trying to figure out why it sounded so rattlely, I was 1 and a half quarts low on the dipstick.

Thanks. I did check it after changing, ran it a bit and let it sit over night and checked it again in the morning. It was full. Thank you though I do appreciate the advice.

 

[carter262]

Ok y'all. First thanks for the replies and help.

Here is what I have found and where I am at.

I ran it up on ramps and pulled the inspection plate. I hate that you have to pull the lines to do this, but whatever. I could find no crank in the flex plate. All the bolts are good and tight. I checked the mounts and other bolts. All look good and tight. I checked the harmonic balancer. Does not appear damaged, no wobble, doesnt move when I try to rotate it. Checked the exhaust and can not find any leaks.

The noise has gotten worse. It appears to be coming from the torque converter. I believe it is going bad. The sound is loud when it is it is at lower rpms. When you increase the rpms the sound goes away, sounds normal, until you let up and the rpms lower. So what do you think. Does this sound possible? Could It still be something else that I am missing?

This really sucks. I just put it in around a little under a year ago. I was also told that if the torque converter goes bad metal gets into the transmission and ruins it. Is this true. Do I need to rebuild the transmission too?

Also does anyone know the part number for the correct torque converter for a M1009? The parts manual does not list GM's part number.

 

[cucvrus]

To be safe I would say yes. it will send the particles through out the entire transmission. Also the radiator cooler will need to be flushed. Sorry. I was hoping for an easier fix.

 

[Warthog]

If you need a torque converter I have a couple dozen 6 bolt units. I have the part number at work. I'll post it tomorrow.

 

[carter262]

If you need a torque converter I have a couple dozen 6 bolt units. I have the part number at work. I'll post it tomorrow.

Yes I do believe that I will need one thanks. I found this GM number on another thread where you posted it (8656942). If you want IM me the cost.

Also have you every had a torque converter go out before? Does it sound like I am right that mine is going out after around a year being installed?