I need some help identifying a clank sound. I’m not sure if it’s the auto transmission (42RLE, not the 45,) rear axle/differential, or the driveshaft. When I accelerate fast (call it 2/3 power but not floored) I will get a loud clank coming from the rear of the Jeep when shifting from 1st to 2nd, sometimes but not as often it’ll happen from 2nd to 3rd. In addition to the clank the Jeep lurches a bit as if I had a manual transmission and dumped the clutch a little too soon. The sounds, and force is much worse if I happen to ease off the gas right before it happens.

Below are the links to 3 videos I took on a cell phone while under the jeep. It’s not the best quality but hopefully someone can tell me what their thoughts are and what my next step should be.

http://www.youtube.com/watch?v=iRdDcfU6230
http://www.youtube.com/watch?v=UhhRNJT8QtA
http://www.youtube.com/watch?v=XNbdpkNifWo

Additionally, since I purchased the Jeep with 30,000 mi on it (now 80,000) it has always had a soft clunking sound and feel when going from idling in drive (like in traffic) to just on the gas while in Full-Time four wheel drive. It is not an issue in 2wd or in 4x4 Part Time. Since I’ve had this clanking issue going from 1st to 2nd gear (with the auto transmission) the lag in the 4x4 Full Time mode seems to be getting worse.

Thoughts?

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(Formerly just “scoobysnax”) '04 Liberty Limited - 245/70/16 Firestone Destination AT's, Mopar tow hooks, Draw-Tite Class IV hitch, Skid Row Engine & Transmission Skids, Mopar T-Case & Gas Tank Skids, Extended Breather Tubes, Red Top Optima, Sylvania Silver Star head lights, Hella 500FF bumper mounted driving lights

Is it 4 Wheel Drive Lock? I have a KK with a part time only 4x4 system. You're only supposed to use it in poor traction situations, use on a dry, paved, highway can cause binding, wheel hop, etc. That can cause loud clanking noises and damage the transfer case and drivetrain.

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2008 Jeep Liberty KK, SkySlider, Tow Package, OME/Bilstein Lift, Flowmaster Delta 50, Removed Resonator, DuraTracs, In-dash CB, PIAA 520 ATPs, Dual KJ Tow Hooks
http://www.cardomain.com/ride/3974106/2008-jeep-liberty
Lost Jeeps PNW/BC Members Map

You're going to have some play in there
How is the boot on the rear of the front drive shaft? Have you checked that yet?

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MUDD'S MOTORSPORT'S We do IFS lift installs ,
03 OVERLAND EDITION /Kilby-Skidrow-Mopar-4XGuard skids/ 2.5 inch TOTAL CONTROL JBA coilovers -JBA Arms/MOABS-31 FALKEN WILDPEAK AT3W / 4.10's etc, 04 Kilimanjaro Edition loaded, plus 05 KJ limited

The boot on the front of the front drive shaft (going to the front dif) has a little oil/grease on it but it’s always been like that. I think I have to remove the transmission skid plate to see the back of the front drive shaft coming out of the T-case and I haven’t had a chance to do that yet.

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(Formerly just “scoobysnax”) '04 Liberty Limited - 245/70/16 Firestone Destination AT's, Mopar tow hooks, Draw-Tite Class IV hitch, Skid Row Engine & Transmission Skids, Mopar T-Case & Gas Tank Skids, Extended Breather Tubes, Red Top Optima, Sylvania Silver Star head lights, Hella 500FF bumper mounted driving lights