More of a clunk than what i'd call shudder

k9adv · **Posted:** Tue Jul 31, 2018 9:07 pm

New to me 05 CRD Limited.

I am third owner, second owner had it since 5000 miles or so.

They state the F37 recall was done in 2007 or so, and the transmission was rebuilt 2 years/30,000 miles ago. No detailed info as far as if it now has an upgraded TC (I suspect not) or the upgraded mopar pump.

I have a clunk, a single clunk, that happens when i am running at 55-60 and i left off the accelerator. It has happened 3 times so far.

Could this be a variation of the shudder?

Near future plans are Suncoast converter, upgraded mopar pump, and transgo HD2 kit install (including the in pump parts).

WWDiesel · **Posted:** Tue Jul 31, 2018 10:19 pm

Letting off the accelerator does not produce the torque converter shudder which is caused by the clutches in the TC slipping and chattering while the vehicle is under load and the TC is in a locked up condition.
First thing to check is the boomerang control arm on top of the rear axle.
It has a big single ball joint that can get worn out as well as two very soft rubber bushings that wear out and allow a loud clunking sound to resonate throughout the vehicle when upshifting or downshifting as they are mounted right under the rear seat area on each side of the body.
Another thing to take a close look at is the U-Joints on the driveshift. If one or both of them are worn out, they can make the noise you are hearing. :roll:

k9adv · **Posted:** Tue Jul 31, 2018 10:31 pm

thanks.

yeah, there is no clunk/noise/shudder/anything at any other time, whether upshifting or downshifting.

I've checked the boomerang and the ujoints. will check them again.

rancherman · **Posted:** Tue Jul 31, 2018 10:45 pm

will the noise replicate itself with repetitive throttle action? Or is it only occasionally? can you hear a clunk by going from drive to reverse with brakes applied. If so, find someone you TRUST... and you get down/along side when they do this, and listen/zero in on the area.

Are all four tires exactly the same size? brand, model, amount of wear?

Check your rear trans mount for looseness, both the crossmember and the rubber isolator.

k9adv · **Posted:** Tue Jul 31, 2018 10:56 pm

only seems to be occasional.
dont recall a clunk when going from drive to reverse. will double check that tomorrow.

all our tires are same, minimal wear difference.

will check trans mount. thanks.

rancherman · **Posted:** Wed Aug 01, 2018 9:19 am

k9adv wrote:

only seems to be occasional.
dont recall a clunk when going from drive to reverse. will double check that tomorrow.

all our tires are same, minimal wear difference.

will check trans mount. thanks.

with the full time/part time 4X4, and who-knows-what for locking differential, an 'odd' size tire can get some pretty good 'wrap up' in the drive line..

If you can, put some 'juice' to the engine when torqueing against the brake.. Just enough to cause a pretty good 'torque-over', but not enough to cause it to over come the brake. (let off when rolling through neutral) and hit it again in opposite gear. This 'should' cause the loose component to stand out.

Is the clunk 'felt' as well as heard? or is it more a body 'boom'?

k9adv · **Posted:** Wed Aug 01, 2018 9:27 am

full car boom.

APC9199 · **Posted:** Wed Aug 01, 2018 12:09 pm

I would bet that it is a combination of rear boomerang and u-joints. as the ball joint and bushings in the rear uca wear out it allows the rear diff to rotate up and down when torque is applied and released. I believe the clunk is the u-joint binding as the angle suddenly changes. Mine has been doing this primarily when I shift into drive, but also occasionally when I accelerate hard through a shift or let off the accelerator after a hard pull. The shop that I paid to replace the bushings and ball joint in the rear boomerang botched the job and now it is worse than ever. I am installing the Ironrock rear uca that a lot of people have been talking about lately. Hopefully that will get rid of the problem without needing new u-joints, because I just did them when the shop did the rear uca for me.

k9adv · **Posted:** Wed Aug 01, 2018 12:20 pm

APC9199 wrote:

I would bet that it is a combination of rear boomerang and u-joints. as the ball joint and bushings in the rear uca wear out it allows the rear diff to rotate up and down when torque is applied and released. I believe the clunk is the u-joint binding as the angle suddenly changes. Mine has been doing this primarily when I shift into drive, but also occasionally when I accelerate hard through a shift or let off the accelerator after a hard pull. The shop that I paid to replace the bushings and ball joint in the rear boomerang botched the job and now it is worse than ever. I am installing the Ironrock rear uca that a lot of people have been talking about lately. Hopefully that will get rid of the problem without needing new u-joints, because I just did them when the shop did the rear uca for me.

thanks. it is pouring out right now, i will check mine again after it stops.

I will consider the Ironrock and Arkady's setup if i need to replace the boomerang.

APC9199 · **Posted:** Wed Aug 01, 2018 3:02 pm

k9adv wrote:

APC9199 wrote:

I would bet that it is a combination of rear boomerang and u-joints. as the ball joint and bushings in the rear uca wear out it allows the rear diff to rotate up and down when torque is applied and released. I believe the clunk is the u-joint binding as the angle suddenly changes. Mine has been doing this primarily when I shift into drive, but also occasionally when I accelerate hard through a shift or let off the accelerator after a hard pull. The shop that I paid to replace the bushings and ball joint in the rear boomerang botched the job and now it is worse than ever. I am installing the Ironrock rear uca that a lot of people have been talking about lately. Hopefully that will get rid of the problem without needing new u-joints, because I just did them when the shop did the rear uca for me.

thanks. it is pouring out right now, i will check mine again after it stops.

I will consider the Ironrock and Arkady's setup if i need to replace the boomerang.

Just had another thought. Check the top and bottom nuts on the motor mounts and make sure they are seated properly and snug. This will usually cause problems when shifting but I can see how it might do odd things with acceleration as well.

k9adv · **Posted:** Wed Aug 01, 2018 3:48 pm

will do. will check motor mounts, tranny mount/crossmember mounts, ujoints, boomerang, and all other suspension when it dries up...monsoon conditions here. thanks for the suggestions. i appreciate it.

More of a clunk than what i'd call shudder

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