Noticeable Clunk When Putting Jeep into Drive or Reverse and Occasionally While Driving

[rjley]

I've seen this posted before was didn't see an explanation or a fix for it. When I put the Jeep into Drive or Reverse there is a noticeable "clunk". This seems to go away a bit if the car's been warmed up for a bit. I also get this when I'm driving if I put my foot on the gas, break, and gas again (not every time, but a noticeable amount). I'm not sure if this is a known issue and there's a checklist I should follow to fix it or if it's just how the transmission is. Anyone else experiencing this?

Sponsored

 

[DanW]

Mine does it when putting into reverse when cold. Completely goes away when warm. I have never noticed it when shifting into Drive.

I've felt this is pretty normal, but then again I've not owned a vehicle I've driven often with an automatic for awhile.

I have 48k miles on it and am planning to do a drain/fill/filter change on the transmission soon. It will be interesting to see if this goes away or is reduced with new fluid. Transmission operating temps appear normal, including when towing.

 

[00Mutt]

My car fixing knowledge is pretty dated, as in when I was in High School 94-98. But Back then I drove a few beaters that needed constant love, mainly because I would go mudding a whole lot. Back then, that was typically an indication that the u-joint was getting worn and would have slack in it giving that lovely clunk when you would put it in gear. Not saying this is the issues, it very well could be something else, but honestly, unless an actual mechanic tells you different, I would start there. Just shimmy under your baby and twist the drive shaft back and forth to see if you have some sloppiness.

 

[rjley]

Mine does it when putting into reverse when cold. Completely goes away when warm. I have never noticed it when shifting into Drive.

Next time you drive it if you think about it, around 10 MPH let off the gas, break, and then hit the gas again and let me know if you hear anything. Thanks!

 

[DanW]

Next time you drive it if you think about it, around 10 MPH let off the gas, break, and then hit the gas again and let me know if you hear anything. Thanks!

Will do!

 

[Wheelin98TJ]

Check rear driveshaft u-joints.

 

[DanW]

Next time you drive it if you think about it, around 10 MPH let off the gas, break, and then hit the gas again and let me know if you hear anything. Thanks!

Tried that. I didn't feel or hear anything that felt abnormal.

 

[JW Jeep]

Mine does it alittle once in a while but not always and it never bangs ? I posted on here about it when it was new. Never has it got worse and seems to me like play in rear differential but someone on here I thought said it was rock climbing mode or something like that. It never comes to a stop it will just keep going without hitting brakes even up inclines ? It’s almost like something kicking in and out ? Maybe it isn’t play ? Whatever it is I sorta just got use to it. When we went to Yellowstone a couple years ago it was stop and go really bad and just crawling, that’s where I first noticed it on mine.

 

[ZeeJay]

Block front wheels, place in neutral and maybe necessary to jack up rear enough to daylight tires thanks to the smarter than us electronics . Check u joints, pinion bearing and pinion backlash, check rear tire lug torque as well. Good starting point for unusual noise into or transition from selected gear or a noise associated with decel to accel.
Not knowing what the noise is exactly I would advise this at least. Mine will on occasion “thunk” pronouncedly on either forward or reverse selected gear depending how it was parked and whether drivetrain was slightly bound. Also if clumsy with throttle input in traffic as an example have noted pinion slap which again makes a thunk with 11,700+ miles. It’s all relative though, anybody who’s been around 4.0s knows that it sounds like rear end is about to rip out when they hit a gear. A 4.0s liner torque makes a bitch out of pinions and drivelines.

 

[JW Jeep]

To add to my earlier post, mind doesn‘t do it (clunk)putting into gear. only when crawling at very low speeds which it seems to have a mind of its own and it doesn’t idle high with the 8 speed trans. It’s like something kicks in and out to keep it moving and notice it when feathering the gas pedal ever so slightly on and off At like 5 -10 mph. I’m Ocd and most people probably wouldn’t even notice this

 

[Sbro2021]

Gonna throw this one out because mine has a dull drivetrain clunk sometimes. I'm chocking mine up to excessive backlash in the rear end gear set. I haven't measured it yet mostly because I don't care enough to do anything about it and don't want to invest in changing gears, but mine has a very open gear mesh. Just a thought.

 

[DBravo]

I've seen this posted before was didn't see an explanation or a fix for it. When I put the Jeep into Drive or Reverse there is a noticeable "clunk". This seems to go away a bit if the car's been warmed up for a bit. I also get this when I'm driving if I put my foot on the gas, break, and gas again (not every time, but a noticeable amount). I'm not sure if this is a known issue and there's a checklist I should follow to fix it or if it's just how the transmission is. Anyone else experiencing this?

I have this on my 2020 Overland and am at 85k miles with no issues. Have thoroughly checked the drivetrain. It's been there since day one - 95 miles.

 

[Wetzie]

I get a clunk when engaging reverse coming out of the garage. Fresh start while the engine is cold. This has been happening since day one, no known issues.

 

[DanW]

I get a clunk when engaging reverse coming out of the garage. Fresh start while the engine is cold. This has been happening since day one, no known issues.

I really think it is normal. My buddy's JT does it and my brother said his did it. Both are 2020 model years. Mine is a 2021. My ex has a 2021 Wrangler and she said, yup....same thing.

It is a combination of things. First, the transmission is cold and the fluid is more viscous and has not fully circulated to all the parts yet.

Secondly, the engine is at higher idle rpm. I found that if I wait for the engine to settle down to normal idle, the clunk is far less pronounced.

This is going in the "I ain't gonna worry about it" file, for me.

 

[HooliganActual]

I really think it is normal. My buddy's JT does it and my brother said his did it. Both are 2020 model years. Mine is a 2021. My ex has a 2021 Wrangler and she said, yup....same thing.

It is a combination of things. First, the transmission is cold and the fluid is more viscous and has not fully circulated to all the parts yet.

Secondly, the engine is at higher idle rpm. I found that if I wait for the engine to settle down to normal idle, the clunk is far less pronounced.

This is going in the "I ain't gonna worry about it" file, for me.

@rjley I tend to agree with @DanW and others that have expressed a similar sentiment. Mine is a 2020 Rubicon and has done it since Day 1 on cold starts. I'm 30+K miles in at this point and it still does it the same as Day 1; it's no more frequent and no more severe today than Day 1. As a retired Reliability Engineer, these are the kind of things I would teach our technicians from a Root Cause perspective, inasmuch as what you may be hearing is "normal" (if not concerning) but what you should really be paying attention to is whether it changes: frequency, severity, conditions, etc.

The old mechanic's saying of "If it ain't broke, don't fix it" really has some application in the world of Reliability: numerous studies done in the aircraft world, both civilian and military, have recognized that the old "open and inspect" style of preventive maintenance actually introduces failures through improper reassembly, replacement of actually good parts with defective parts, etc. (google "bathtub curves"), so just monitor it and see if it changes...

Sponsored