Odd Reverse Noise

[Pacu]

A local dealership and I can’t figure out what’s causing this noise that only occurs after a long drive (30-45 minutes) and then putting the Jeep in reverse.

The sound lasts about 10-30 seconds and then goes away. The Jeep only has to be in reverse, doesn’t have to be moving in reverse to cause the noise but it noticeably has an affect when turning the tires back and forth.

Dealership has been trying to diagnose now for over a month and tried to tell me it was bad gasoline and that I should use premium gas 91 and higher octane moving forward. This is the 3.6L engine which only requires 87 octane gasoline.

I argued that with it being over a month and it cycling through a few tanks of gasoline that this can’t be the case. It’s on it’s 4th trip back to the dealer.

I did see in the owners manual where slight knocking under low RPM is normal but what is defined as slight?

Any ideas of what this could be? I use my Jeep for off roading and do not want to be left stranded.

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[Upnarms]

Dang,I thought you had a diesel! Sounded worse when you first turned the wheel and thought it might be steering pump or box, but maybe that's just opening up wheel well and making the sound louder .

Did premium cause it to go away? I would at least try it. I got gas in Colorado on a trip and it was 85 octane. Made my engine sound like crap on a Nissan I used to own. Ran premium for a couple tanks and it was back to normal.

 

[Beachcomber72]

Got this exact same noise. You can sometimes hear it very faintly when driving about 45 mph, but yeah as soon as you stop and put in reverse as if you were parallel parking it becomes very loud and distinct. Mines a 2022 High Tide 3.6 Etorque with 14k miles on it. Only thing I can remotely pinpoint is the belt tensioner directly behind the Belt Start Generator. But not 100% verified.

And it’s only after it’s been driven for about 30-45 minutes. Absolutely will not happen when starting up in morning and reversing out of driveway or after sitting for a few hours. Also it’s definitely not differential or transfer case or transmission noise. It’s right in the upper center front of engine.

 

[Beachcomber72]

A local dealership and I can’t figure out what’s causing this noise that only occurs after a long drive (30-45 minutes) and then putting the Jeep in reverse.

The sound lasts about 10-30 seconds and then goes away. The Jeep only has to be in reverse, doesn’t have to be moving in reverse to cause the noise but it noticeably has an affect when turning the tires back and forth.

Dealership has been trying to diagnose now for over a month and tried to tell me it was bad gasoline and that I should use premium gas 91 and higher octane moving forward. This is the 3.6L engine which only requires 87 octane gasoline.

I argued that with it being over a month and it cycling through a few tanks of gasoline that this can’t be the case. It’s on it’s 4th trip back to the dealer.

I did see in the owners manual where slight knocking under low RPM is normal but what is defined as slight?

Any ideas of what this could be? I use my Jeep for off roading and do not want to be left stranded.

Any further updates on yours?

 

[Beachcomber72]

Same as in this video too…

 

[Byrds8]

I hear something similar in mine also from time to time. Been wondering what it was.

 

[Athenstim]

I have experienced this noise also in Reverse. Sounds like a diesel . (but 3.6 Gas)

 

[Riotfunk]

Piston slap maybe. That sounds motor related. Doesn’t sound like low octane knock. As the motor heats up to operating temps those clearances change slightly. Might be why you only hear it after running it a bit.

Have them cam the cylinders or pull the head to see them.

 

[Byrds8]

Drove the wife's yesterday and it sounds like Beachcomber72's also.

 

[DMT]

Same sound. Reverse gear. Backing up and turning steering.

 

[KCSgtMaj]

Bad/worn thrust washers? How many miles?

 

[HiJinx69]

Same as in this video too…

That's my jeep! That was a while back. I no longer have that issue. It just went away. I did use higher octane gas for a bit, thinking it was engine knock, but didn't help. If I remember correctly, it was over two/three years ago.

 

[IanNubbit]

I does sound mostly like a fuel delivery/timing issue tbh. While the octane level might not be the actual issue, it does help with stale gas. When you say you offroad mainly, that tells me gas sits for a long time. I'd recommend put some fuel injector cleaner in a 50-100% full tank, preferably 2 times the recommended amount. Then run that tank completely down. like light on, no range left, not run out, but go till it says low range and go another 10 miles. Then fill it with the highest rated fuel, and add another good injector cleaner in that tank, either one or double the recommended here. run that all the way down till empty. as well then go back to normal. You are also going to want to do this all within like 2 days, just burn through both tanks fast as possible. After that go back to regular fueling. ~$200 is a lot better than an engine, also keep the receipts and put the mileage and date on them so you can prove it to the dealer if it continues. This will completely rule out fuel for you.

I normally only see this on low mileage vehicle that sit for extended period of times, or only short trips. From experience, people have thrown engines at the vehicle and it did not repair the issue.

 

[Byrds8]

I put midgrade in mine the past few fillups and I do not believe I have heard the sound since. I will be doing the wife's the same way her next fill up to see if that helps with anything on hers.

 

[SUGARPLUMMER1]

Does anyone have any updates on this issue? I have the same knocking sound when I put my Jeep in reverse and turn the wheel after driving 20 min to work every morning. Took it to my dealership and the mechanic said he’s never heard that sound before. He added an octane additive to the fuel and said if that doesn’t solve the issue I’ll need to bring it back for a deeper dive into the issue. Thanks for any replies.

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