Engine has a rhythmic ticking noise when under load, once the engine is warm and poor MPG?

LESLEY RICKARD MCKINNEY

MEMBER
2009 HUMMER H3
3.7L
5 CYL
4WD
AUTOMATIC
91,600 MILES

My vehicle listed above has a rhythmic ticking noise when under load, once the engine is warm. Gas mileage was severely decreased, and it would sometimes feel like it went into limp mode that would resolve by turning off the engine then restarting it.

The GM dealer (with three old Hummer tech holdovers) said it was the transmission. A second opinion told me it was the transfer case. Replaced transfer case but it did not fix the problem.

I took it to a transmission shop. They replaced the torque converter and flex plate. Also checked out the transmission. Did not fix the problem. They said take it to an engine shop.

The engine shop said they were not able to determine what the problem was, and the truck wasn't throwing any codes. They suggest an engine rebuild.

Since I've already put about $6,000.00 into this problem which includes all the major work done, different diagnostic visits, and the fixing of several "small" things that it could have been, I want to make super sure I've ruled out everything before I pour the quoted $11,000.00 to $12,000.00 that they're quoting me for the rebuild. (Yes, everything else like exhaust manifold leak, lifters, etc. That would cause a ticking noise have been ruled out.)

Since all of the initial thoughts were that it was drivetrain related, I'm not sure that after all of the work that's been done it's actually powertrain. So, my first question is whether the problems I described along with the early diagnosis of a bad transfer case could actually be the result of an issue with the TCCM?

Second, when does a TCCM have to be re-flashed? If I replaced the transfer case with a rebuild, does any attention have to be paid to the TCCM?

Third, if the above are "no, " can you think of anything else I should look into or think about before going the engine rebuild route? If not, and considering what the rebuild is going to cost, I'm about to have a very large paperweight that I'm making a car payment on.

4 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,909 POSTS

I would say no to all the above, let's start over and before we spend any money, we will be sure of what's going on. The first thing I need is a clear video of the engine noise and where you feel the noise is coming from.

Also, has the oil changes and filter been kept up regularly. Also, does it make the noise when the car is stopped? So, here is an exploded view of the engine, please look them over and when you hear the noise try to imagine where the noise is coming from. This engine has a balance shaft set up that can go bad which is at the rear of the engine. Try to imagine if the noise is toward the top of the engine or down low. It could be a broken piston ring or a seized wrist pin in a piston.

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

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Sunday, July 31st, 2022 AT 1:10 PM

LESLEY RICKARD MCKINNEY

MEMBER
3 POSTS

I bought the truck 90 days ago and have put about 500 miles on it. I can't speak to the oil change history, but the dealer inspection paperwork says they changed it, I had it changed again when I first heard the noise, and one more time a few days ago to see if heavier oil would help. The Carfax report I downloaded lists some oil changes, but I don't know if that's all. The report also first mentions a "noise" about 10,000 miles ago.

I can't really get pics or a video of the engine that includes the noise since it's only under load. I don't hear it in park or neutral.

Of the mechanics who have used a stethoscope, the deal said they heard it from the transmission, another said transfer case, another said he heard it somewhere between the 3rd and 4th cylinder, and the one who did the torque converter/flex plate, said it was louder underneath than above. When I'm driving, I'd estimate the sound is coming from in front of me at approximately the 1 o'clock position.

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Sunday, July 31st, 2022 AT 3:35 PM

KEN L

MASTER CERTIFIED MECHANIC
42,909 POSTS

Yep, that to me says balance shaft chain or shaft bearing issue. These engines had problems with the balance shafts. They are difficult to get to because they are at the rear of the engine. This is what the manual says on how to replace or inspect the operation of the shafts. Does this sound like where it is coming from? As you can see the engine needs to be removed to do the job. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is; it could be the bearings in the block.

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