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Bad milage and clunk

Willy1803

By Willy1803
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Willy1803 New Member

Willy1803

Posted
Posted (edited)

I have a 2017 Chevy 1500 lt with 111k on it my gas mileage as been just dropping I'm average miles per gallon on highway is 14 I average about 9 in town I don't constantly floor it but when I first got it I was getting mid 20 on highway and I've noticed a drop in power and clunking in the rear when I back up in snow I have replaced shock in struts dose clunk when i hit pot holes sometimes the last time I changed the oil there was alot of shaving in my oil

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swathdiver Senior Enthusiast

swathdiver

Posted
Posted
8 minutes ago, Willy1803 said:

I have a 2017 Chevy 1500 lt with 111k on it my gas mileage as been just dropping I'm average miles per gallon on highway is 14 I average about 9 in town I don't constantly floor it but when I first got it I was getting mid 20 on highway and I've noticed a drop in power and clunking in the rear when I back up in snow I have replaced shock in struts dose clunk when i hit pot holes sometimes the last time I changed the oil there was alot of shaving in my oil

Might have a few issues going on at once.  I wouldn't drive it.  Might want to send out an oil sample for analysis but it might be moot at this stage since you have shavings in your oil.  Better check the going rate and availability for used motors in your area.

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

Yep, unfortunately it could be one or every driveline component failing. 

 

My '07 started burning oil at 50k miles, now at 117k, oil pressure is dropping off quick. At 97k, I found chunks of metal in the rear differential during a fluid change. It was the tips of both spider gears which broke off for no good reason (cheap Chinese metals GM sourced) and ruined the side gears, and the associated metal wiped out the entire carrier assembly. It had .011" backlash, and tons of slop on the center pin. Then at 103k, 3rd and 4th gear burned up in the transmission.

 

The transfer case on mine is still alive, but that thing always has chunks of metal on the magnet every 50k when I change it.

 

Unfortunately nothing is built to last anymore. These engines and drivelines are notoriously failure prone in a hundred different ways each. If the engine has become noisy along with the metal, its days are numbered. I'd check everything else too for excessive drag, and metal in the fluid. Might be in need of everything, including u-joints.

Silverado4x4 Senior Enthusiast

Silverado4x4

Posted
Posted

The rear clunk could be the locker engaging due to wheel slip in the snow and as far as the metal in the oil that motor is on its way out and as said I wouldn't drive it she's going to blow. Surprised you didn't say it was knocking.

Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
Posted

Ya, the rear end clunk can be caused by the limit slip differential doing its thing. Mine does that from time to time.  If you keep the brakes pressed, and shift back and fourth from forward and reverse, any clanking could be bad U-joints.

 

As far as the engine metal is concerned, it should be diagnosed ASAP. One way to do that is to inspect the metal and determine where it came from based on its shape, size, and type of metal.

 

If the motor is losing a lot of metal, then you have problems. Maybe the cam is going bad, or maybe the lower rod bearings are on their way out.

 

 

Here is a very useful way to find out exactly what is happening inside your motor:

 

 

 

 

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