Help me find the CLUNK

[mrogerc]

I have a Trilogy supercharged '04, and have had both a tranny failure and a rear axle break (too much fun). I now have a Eaton posi unit. I also replaced the contol arms and Watt's link with the Metco parts. Bottom line is that the suspension and drive train have lots of work on them.

I have an annoying symptom--a clunk sound from the rear end. It does not appear when I move from park to drive or reverse, nor does it show up on acceleration or braking.

It only makes the noise if after accelerating, I take my foot of the gas suddently. It is quite noticable--I can feel the clunk--at about 15-20 mph, much less at higher speeds.

I will be inspecting the drivetrain and rear suspention tomorrow, including checking the driveshaft, the backlash in the rear end, and the tightness of all suspention components.

Anything else????

Mike

[CBT]

Put it on a dyno and watch for excessive up and down travel where the drive shaft meets the pumpkin.

[ghost03]

Did you install a Shift Kit in your tranny? I have a similar noise but it usually happens when I accelerate then let off suddenly.

If you have addco sway bars check the grease fittings. They might be kinda dry and need to be greased again.

[mrogerc]

[QUOTE=ghost03;502413]Did you install a Shift Kit in your tranny? I have a similar noise but it usually happens when I accelerate then let off suddenly.

Actually, you are concisely describing when I hear this noise. Do you get it at similar speeds? How long/for how many miles has it been going on?

My tranny had the "J-mod" done on it. Could that have some thing to do with this?

Also, the Metco parts do have grease zerks on them--they are getting nicely filled with synthetic grease tomorrow.

[ghost03]

[quote=ghost03;502413]Did you install a Shift Kit in your tranny? I have a similar noise but it usually happens when I accelerate then let off suddenly.

Actually, you are concisely describing when I hear this noise. Do you get it at similar speeds? How long/for how many miles has it been going on?

My tranny had the "J-mod" done on it. Could that have some thing to do with this?

Also, the Metco parts do have grease zerks on them--they are getting nicely filled with synthetic grease tomorrow.The noise I heard with the Metco's were when I would reverse in to a parking spot with a little heavy acceleration about 8 out of 10 times, Once I greased them it went away.

As far as the Tranny noise I hear and feel it when I go over 15MPH. It usually happens when the gear is about to swich to the next one and I let off. It souns and feels like its coming from the rear but its actually right underneath you. I just learned to deal with it

[mrogerc]

[quote=mrogerc;502415]. It souns and feels like its coming from the rear but its actually right underneath you. I just learned to deal with it

How did you determine that the sound was coming from underneath?

[Badger]

I have the metcos and I'm experiencing the clunk as well.
Will any synth grease do?
It only happens when I go from forward to reverse or engine braking.

[ghost03]

I have the metcos and I'm experiencing the clunk as well.
Will any synth grease do?
It only happens when I go from forward to reverse or engine braking.I use only pure synthetic grease. You'll need a grease gun with a flexible hose to reach the fittings

[fastblackmerc]

I use only pure synthetic grease. You'll need a grease gun with a flexible hose to reach the fittings

Also recheck the torque on the attaching bolts/nuts.

Search for the torque settings.

[pantheroc]

I have leaking rear right shock. I think that is what rarely clunks on me.

[mrogerc]

I got under the car today, checked the rear end backlash, the suspension bolts, etc, and found no issues.

I also greased all 12 zerks on the Metco parts, went for a test drive, and the clunk was much quieter.

Maybe this clunk is primarily a result of the firmer bushing surfaces?

[ghost03]

I got under the car today, checked the rear end backlash, the suspension bolts, etc, and found no issues.

I also greased all 12 zerks on the Metco parts, went for a test drive, and the clunk was much quieter.

Maybe this clunk is primarily a result of the firmer bushing surfaces?How much grease did you put in. I had to fill them until it overflowed cuz they were pretty much bone dry. I havnt heard the noise since oiling them

[mrogerc]

How much grease did you put in. I had to fill them until it overflowed cuz they were pretty much bone dry. I havnt heard the noise since oiling them

The lower control arms and the Watt's link--not too much. The upper control arms took quite a bit. I ran out of time, but soon I am also going to put a torque wrench on the control arms to make sure all is well.

[Steve_NC]

Front sway bar bushing 46 foot pounds. Front sway bar end links also 46 foot pounds. These numbers are from the DVD manual. Also, check to make sure that the front sway bar end links have not failed. I had the right link fail on me recently.

[RCSignals]

I got under the car today, checked the rear end backlash, the suspension bolts, etc, and found no issues.

I also greased all 12 zerks on the Metco parts, went for a test drive, and the clunk was much quieter.

Maybe this clunk is primarily a result of the firmer bushing surfaces?

Those bushings shouldn't be causing a 'clunk' Squeaks yes, unless greased.

[MENINBLK]

Put the shifter in 1.
Drive up to 10 mph and take your foot off the gas.
Do you hear the clunk ?

Step back on the gas.
Do you hear the clunk ?

If you do it is the gear lash betwen the pinion and the ring.
I have it on mine from the factory.
It will do no harm.

[Aren Jay]

The clunk sounds like every car I've ever owned.

In my Firebird the dealership insisted it was the catalytic converted bouncing off the frame. I thought it was the transmission. Their fix never worked. In my Mustang it was definitely the transmission. I was later told that it wasn't anything to worry about something about how automatic transnmissions work with clutch plates.

I don't know to much about it though. I havn't noticed it on the Maruader yet. But then the Maruader is still newish.

[mrogerc]

IT looks like my belief that lubricating the Metcos reduced the Clunk was premature. Either it was the placebo effect, or some other condition reduced the noise temporarily.

In any case, it seemed to be back, so I did a few experiments:

Transmission in 1, accelerate to 20MPH, take foot off throttle: NO CLUNK.

Transmission in 2: accelerate to 20MPH, take foot of throttle: NO CLUNK.

Transmission in D: accelerate to 20MPH fast enough to stay in 1st gear, take foot of throttle: NO CLUNK.

Transmission in D: accelerate slowly to allow 1-2 shift to 20MPH, take foot of throttle: CLUNK.

So, the clunk only happens when the tranny is in Drive, and only above 1st gear. Overdrive on/off does not matter.

I am concluding that what others said is right, this is inside the transmission. Any thoughts about what is causing it? Anyone think it is a real concern?

[ghost03]

I noticed a similar clunk once I installed the Shift Kit. I have asked a few people and they say its normal and nothing to worry about.

[mrogerc]

I noticed a similar clunk once I installed the Shift Kit. I have asked a few people and they say its normal and nothing to worry about.

Which shift kit did you have installed? My car had the J-Mod done.

[Zack]

Wow, I just found this thread.

Told ya so!

[mrogerc]

Wow, I just found this thread.

Told ya so!

Hi, Zack. What is it you told us?

Thanks!

[ghost03]

Which shift kit did you have installed? My car had the J-Mod done.I have the Trans Co shift kit

[ChiTownMaraud3r]

Old thread alert.

My J-modded tranny has the same clunk as described by the OP. Loud clunk when letting off the gas before it shifts.

Can others with a J mod confirm this is normal operation? My oil level is fine and smells great.

[justbob]

Not normal at all. I would check the control arms.


Self proclaimed Builder Of Badassery.

Buy it, Break it, Build it BETTER.
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[fastblackmerc]

Old thread alert.

My J-modded tranny has the same clunk as described by the OP. Loud clunk when letting off the gas before it shifts.

Can others with a J mod confirm this is normal operation? My oil level is fine and smells great.

Maybe u-joints or rear end.