Clunking noise coming from the rear

chitown312

chitown312

New Member
Joined
Dec 4, 2020
Messages
8
Location
Chicago
Hi all,

I’m hoping I can get some feedback on an issue I’ve been dealing with for some years now. I’ve searched endlessly on all Jeep forums and nothing quite matched my issue.

My build:
2001 Jeep TJ AUTO 4.0
4” lift
Stock Dana 30 (front) Dana 35 (rear)

The issue I’ve been having is every time I shift from park to drive (vice versa) or park to reverse (vice versa) it makes a clunking noise comes from the rear. The Jeep itself slightly drops down when any shift is made. There’s no clunk whatsoever once it’s being driven. Again, only when I go to shift to P, D, or R.

My thought was that it could be my rear drive shaft since the previous owner who installed the lift never put in an SYE. I just recently had my T-case rebuilt since that was what the mechanic thought was the underlying issue. I also had him install an SYE kit along with an upgraded drive shaft from Adams as well as the front drive shaft. I picked up the Jeep from the shop and absolutely no noise when shifting. Few days later go out to run some errands, still no issues but when I came home and shifted to park the clunking came back. So I put it back in drive and it clunked, went to reverse and it clunked, back to park and it clunked. I’m at a loss. I’ve been told it could be my rear diff (ring & pinion)? I personally don’t have to ability to check it...

Anyone have any idea what it cloud be?

Also, I had the upper control arms (non adjustable) replaced 2 years ago. Lower controls are fine, however I bought adjustable control arms from Currie for both upper and lower that I haven’t gotten around to installing.

Unfortunately my mechanic has COVID and is on quarantine lockdown for the next 2 weeks so I won’t be able to get it in until then. I might try looking for a different mechanic in any case. I just want to figure out what the issue is since it’s annoying me more then ever especially after dropping all that cash on the rebuild, SYE, and drive shafts.

Any help us much appreciated. Thank you.

-Gio
 
A loose track bar or control arm bolt can cause a clunking noise. I doubt that is what your problem is, but it's worth doing a nut/bolt check that everything is up to spec.
 
Our ‘98 was clunking quite a bit when shifting gears (manual), also was hearing the clunk when driving over some obstacles. A bolt had worked itself out of the mount (driver’s side track bar). I’m surprised it wasn’t worse than just a clunk.
 
If you purchase a lube locker, pulling the cover and inspecting the gears in the 35 is quite simple. But you can most likely rule it out by manually spinning the rear drive shaft by hand back and forth to see what kind of play you have. If you have a good amount of play you would get a clunk from the initial power going to the diff. The real puzzle is why it is clunking when you put it in park, but I dont know a crazy amount about automatics so there could be another power transfer. Have you had someone lay underneath while you just shift between drive and park?
 
U joint? Was the rear most u joint changed when the new sye was installed?

Two things to help further...

When going from drive to park...go to neutral...wait for engagement. Then go straight to Park.

Then going to Drive...go from Park to neutral...wait for engagement (a second or so) then into Drive.

Any noise?

Put in 4wd HI and do your normal shifting abd see if any noise.

Good luck
 
(New Ujoints with the new driveshafts.)
A slight clunk is normal in an auto trans when shifting from park to drive, drive to reverse. It is the internal play in the trans and is perfectly fine. Now a LOUD clunk is different. Get underneath and have a buddy shift the trans. Parking break ON. Wheels chocked. You should see a slight 'shudder' of the driveshaft as the shifting is made. A little shaft movement is still ok. There is a bit of play in the diff as the gears move to contact in the other direction. Same with the trans. If you see the driveshaft rotate like an inch or more when shifting then get the rear diff opened up and see what's going on there.
 
CharlesHS said:
The transmission mount may be going bad
Click to expand...
Second to this. Cheap, easy to replace, and very likely to cause a clunk - potentially a loud, nasty one. Unless you know you have a new one, it's a good idea to replace it. My son tweaked this while learning to drive a manual, the clunk was NASTY.

jesseshoots said:
A loose track bar or control arm bolt can cause a clunking noise. I doubt that is what your problem is, but it's worth doing a nut/bolt check that everything is up to spec.
Click to expand...
Second to this one, too. I had a lighter clunk in the back when changing the direction of torque on the rear axle. It ended up being the passenger rear upper control arm. The upper bushing was separating, allowing the control arm to shift and twist when torqued by the axle.

I also had a clunk resulting from an upper bolt on the driver's side shock backing out. The shock mount was twisting slightly, hitting the loosened bolt for a light clunk.
 
CharlesHS said:
Have you checked where the exhaust crosses over the tcase skid plate ?
The transmission mount may be going bad; could hurt the check the engine mounts too...
Click to expand...
CharlesHS said:
Have you checked where the exhaust crosses over the tcase skid plate ?
The transmission mount may be going bad; could hurt the check the engine mounts too...
Click to expand...
I have not but will add it to my list of things to check. Thank you.
 
joe98tj said:
If you purchase a lube locker, pulling the cover and inspecting the gears in the 35 is quite simple. But you can most likely rule it out by manually spinning the rear drive shaft by hand back and forth to see what kind of play you have. If you have a good amount of play you would get a clunk from the initial power going to the diff. The real puzzle is why it is clunking when you put it in park, but I dont know a crazy amount about automatics so there could be another power transfer. Have you had someone lay underneath while you just shift between drive and park?
Click to expand...
Thanks for the feedback. I had someone look underneath and they saw some play at the rear diff. They think it could be my ring & pinion...?
 
Rubicon88 said:
U joint? Was the rear most u joint changed when the new sye was installed?

Two things to help further...

When going from drive to park...go to neutral...wait for engagement. Then go straight to Park.

Then going to Drive...go from Park to neutral...wait for engagement (a second or so) then into Drive.

Any noise?

Put in 4wd HI and do your normal shifting abd see if any noise.

Good luck
Click to expand...
Thanks for the feedback.

It wouldn’t be the u-joints since I upgraded to Adams Driveshaft Double Cardan with the SYE Kit that I had installed along with an Adams DC front Driveshaft.

No hard clunking when shifting from neutral (engaged) to park nor to drive.

However, there is hard clunking when shifting normally in 4wd H.
 
Goatman said:
(New Ujoints with the new driveshafts.)
A slight clunk is normal in an auto trans when shifting from park to drive, drive to reverse. It is the internal play in the trans and is perfectly fine. Now a LOUD clunk is different. Get underneath and have a buddy shift the trans. Parking break ON. Wheels chocked. You should see a slight 'shudder' of the driveshaft as the shifting is made. A little shaft movement is still ok. There is a bit of play in the diff as the gears move to contact in the other direction. Same with the trans. If you see the driveshaft rotate like an inch or more when shifting then get the rear diff opened up and see what's going on there.
Click to expand...
Thanks for the feedback.

I don’t have the work space to check the rear differential myself since I live in the city (street parking only) so I’d have to take it somewhere or borrow a friends driveway out in the burbs for a day.

As previously mentioned my friend looked underneath and saw some play in the rear and he thinks it could well be my ring and pinion or spider gears but hard to tell without opening it up to see firsthand.
 
CharlesHS said:
Have you checked where the exhaust crosses over the tcase skid plate ?
The transmission mount may be going bad; could hurt the check the engine mounts too...
Click to expand...
I took a look underneath and my exhaust does not cross over the case skid plate so I can rule that out.

Thanks again.
 
jesseshoots said:
A loose track bar or control arm bolt can cause a clunking noise. I doubt that is what your problem is, but it's worth doing a nut/bolt check that everything is up to spec.
Click to expand...
I took a look and there’s no play in
jesseshoots said:
A loose track bar or control arm bolt can cause a clunking noise. I doubt that is what your problem is, but it's worth doing a nut/bolt check that everything is up to spec.
Click to expand...
Thanks for the feedback.

I checked both track bar and control arms and all bolts are on tight.
 
It depends how much play. They aren't wicked tight and can move slightly by hand. Did your friend say they heard that as the noise?
 
chitown312 said:
Thanks for the feedback.

It wouldn’t be the u-joints since I upgraded to Adams Driveshaft Double Cardan with the SYE Kit that I had installed along with an Adams DC front Driveshaft.

No hard clunking when shifting from neutral (engaged) to park nor to drive.

However, there is hard clunking when shifting normally in 4wd H.
Click to expand...
At this point you know it's not the radio. Probably not the windshield wiper. At least the right side...🤣

But on a serious note I'm not sure how you can just rule out anything tied to the drivetrain that's right down the middle.

Just because something was "replaced " wouldn't make it the first time a problem is still there since a component was reused, not tightened, junk brand, and so on and so on.

I wouldn't rule out anything tied to your drivetrain at this point.
 
chitown312 said:
I took a look and there’s no play in

Thanks for the feedback.

I checked both track bar and control arms and all bolts are on tight.
Click to expand...
Did you check all 8 including uppers? (two bolts for each control arm) How did you check? You really need to put a torque wrench on each one and verify. They might seem tight by looking and/or putting a tiny wrench on it but still not tight enough to handle the engine torquing on them.

I would bet one of them is loose from what you are describing.
 
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