Knocking/Clunking in rear?

[TrailJoy]

It's currently -39c, and my "one month old yesterday" Jeep has been making a loud rhythmic knocking or clunking sound from the rear when I drive on rough icy/bumpy roads. My husband did take a look underneath and said everything looked good (nothing hanging) and it's probably just ice and to just keep an eye/ear on it, but me I want to hoist it up and take a look. In a heated garage. LOL

Has anyone else experienced this? We're supposed to warm back up to 0 in five or so days so I'm hoping it will stop, but unfortunately the roads will also melt and flatten out again so I won't be able to recreate the bumpy roads to check.

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[rootbeer]

It's currently -39c, and my "one month old yesterday" Jeep has been making a loud rhythmic knocking or clunking sound from the rear when I drive on rough icy/bumpy roads. My husband did take a look underneath and said everything looked good (nothing hanging) and it's probably just ice and to just keep an eye/ear on it, but me I want to hoist it up and take a look. In a heated garage. LOL

Has anyone else experienced this? We're supposed to warm back up to 0 in five or so days so I'm hoping it will stop, but unfortunately the roads will also melt and flatten out again so I won't be able to recreate the bumpy roads to check.

This link will probably help you out. I think I have the same thing on my 2018 with 30,000 kms. https://www.jlwranglerforums.com/forum/threads/knock-in-rear-with-dana-44.16921/

 

[TrailJoy]

This link will probably help you out. I think I have the same thing on my 2018 with 30,000 kms. https://www.jlwranglerforums.com/forum/threads/knock-in-rear-with-dana-44.16921/

Thank you, but mine ONLY clunks when I'm driving (slowly) on a very bumpy road. Not at idle or with my foot of the gas. It's the rocking of the vehicle that causes the sound. I also don't have a lift kit. I'm fairly certain it's just ice, but I'm curious if others have experienced the same thing. My husbands truck made a similar noise this morning, but the noise on the Jeep is much louder (and MUCH bigger).

 

[JO DYRT]

By the title I was going to ask if you had a dead body in the rear that was rolling around during turns.

I did not notice any sounds in mine last time I was driving through snow and ice, but it was not that cold either.

 

[viper88]

It's currently -39c, and my "one month old yesterday" Jeep has been making a loud rhythmic knocking or clunking sound from the rear when I drive on rough icy/bumpy roads. My husband did take a look underneath and said everything looked good (nothing hanging) and it's probably just ice and to just keep an eye/ear on it, but me I want to hoist it up and take a look. In a heated garage. LOL

Has anyone else experienced this? We're supposed to warm back up to 0 in five or so days so I'm hoping it will stop, but unfortunately the roads will also melt and flatten out again so I won't be able to recreate the bumpy roads to check.

I had to look up a temp conversion and did a double take. -39C equals -38F! A rhythmic sound or noise means it's happening on rotation or something. Take it in and have it checked out. Make sure it's not a bad drive shaft, U-joint, differential, or loose wheel lugs. Did you guys double check to make sure nothing is wrapped around the drive shaft? Congrats on the new JLU and stay warm!

 

[viper88]

By the title I was going to ask if you had a dead body in the rear that was rolling around during turns.

I did not notice any sounds in mine last time I was driving through snow and ice, but it was not that cold either.

Now how cold can it possibly get in OC CA??? lol.

 

[viper88]

Thank you, but mine ONLY clunks when I'm driving (slowly) on a very bumpy road. Not at idle or with my foot of the gas. It's the rocking of the vehicle that causes the sound. I also don't have a lift kit. I'm fairly certain it's just ice, but I'm curious if others have experienced the same thing. My husbands truck made a similar noise this morning, but the noise on the Jeep is much louder (and MUCH bigger).

From this description, maybe a chunk of ice lodged between your exhaust or suspension and body? Or maybe a broken exhaust hanger?

 

[rootbeer]

Thank you, but mine ONLY clunks when I'm driving (slowly) on a very bumpy road. Not at idle or with my foot of the gas. It's the rocking of the vehicle that causes the sound. I also don't have a lift kit. I'm fairly certain it's just ice, but I'm curious if others have experienced the same thing. My husbands truck made a similar noise this morning, but the noise on the Jeep is much louder (and MUCH bigger).

Well I hope its not the rear end. Have you checked the compartment in the back to make sure the jack and the related tools are all secured? Just a guess, never know. This did this just start happening or did it start when you put new wheels/tires on? That is when i could hear my rear end start making noise, mine is also has no lift.

 

[viper88]

Well I hope its not the rear end. Have you checked the compartment in the back to make sure the jack and the related tools are all secured? Just a guess, never know. This did this just start happening or did it start when you put new wheels/tires on? That is when i could hear my rear end start making noise, mine is also has no lift.

Double check those wheel lugs.

 

[JO DYRT]

Now how cold can it possibly get in OC CA??? lol.

Well the snow was in the mountains, not here in OC. At the time it was in the 40's

 

[TopsOff]

Wipe down the tailgate weatherstripping with 303 protectant. I'm betting that's what it is. When it dries out anytime the jeep rocks it will pop and clunk. We test drove a 2018 and walked away from it because we overthought the issue. Then I had a rental and it did same thing so I got in back while the wife drove and determined it was coming from the tailgate. Wiped it down with a little dielectric grease and it was perfect. On mine I use 303 about once a month. The dielectric lasts longer but attracts dust. I hope this is your issue and it's simple.

I just swapped JLUR suspension into my Sport and the spare tire is tight on that smaller tire carrier. First test drive I heard clunking. Overthought it again.......it was coincidentally time to 303 the seals.

 

[Sean L]

Well the snow was in the mountains, not here in OC. At the time it was in the 40's

Apparently you're never allowed to leave the county...

 

[TrailJoy]

Wipe down the tailgate weatherstripping with 303 protectant. I'm betting that's what it is. When it dries out anytime the jeep rocks it will pop and clunk.

I just took EVERYTHING out, checked the jack (all good) and am going to go back for another test drive after lunch. I took another look underneath and didn't see any signs of snow or ice either, but this comment has me curious as I DID hand wash the windows and the tail gate right before the cold snap (I also hand dried it, but...). My biggest concern though is the tires. We recently put on KO2's with a -12 offset (lugs are good - we retorqued them twice to make sure), but I didn't realize that the factory offset is +44.5. No wonder my spare sticks out so far!! Naturally this concerns me greatly that it's creating some sort of bad juju in the suspension. My husband is going to drive it back to the tire place to discuss it later after I pick up the kids from school.

 

[TrailJoy]

Sometimes I'll do something and my husband will look at me lovingly and say "You're so pretty". Well today I must be DROP DEAD GORGEOUS. lol See here in Canadia, we're not all smart. And if we were, I would have thought to empty the back out BEFORE starting this thread. But I'm new, and you all are so helpful!

Spoiler alert... The clunk is gone. Or at least I couldn't trigger it with an empty Jeep, and I think I know what happened. But I think I had two problems. LOL The knocking sound started a week or so ago. We looked underneath, saw ice, made an assumption and decided to keep an eye/ear on it. Then a few days ago I bought a couple sand bags, and the noise progressively got worse (and by worse I mean more frequent, and louder). So what I THINK happened is the first sound (was a smaller knock/clunk sound) was ice. Then the ice fell off and was replaced by frozen sandbags.

SHEESH! I'm going to leave them out for a few days to make sure the sound doesn't come back, but Y'AAALLLLLL...! It's a good thing I'm pretty.

 

[Kripas]

Following, I have same issue , Can only hear on bumpy road on 20 to 35 miles speed.

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