I having an issue with any sudden change in speed I feel a thud from underneath. It almost seems like the drive shaft has play in it. Lets say I'm cursing at 40mph and let of the throttle and get right back on it I get a thud if you feather the throttle it will thud at any change in speed. Once is a while I get a hard shift into 2nd not sure if the issues are related.

Check drive shaft "U" joints and slip joint. Former may need to be checked by dropping drive shaft as failure is often not obvious on vehicle. Latter just needs cleaning and greasing.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

I'm gonna bet the rear end spider gears are worn on their splines, or perhaps the rear
axle bushings are shot. See the following links to see what is common on high mileage 8.25 Chrysler
rear ends.

https://www.youtube.com/watch?v=LXrv4ARy_Kw

https://www.youtube.com/watch?v=E39DDxZ6LwI

I love the first video, they don't make them like that anymore...

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.

My U joints seized and I pick my KJ up tomorrow from the dealer with a new driveline installed. I purchased an extended warranty from Mercury when I bought the car so its costing me $165.

At very slow speeds I could hear the U joints squeak which is why I took it in.

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2006 Jeep Liberty Limited CRD (purchased 10/30/12 w/ 52k miles) GDE HotTune & Eco TCU, Suncoast TC, Amsoil Full SAPS (EFM) 5w40, Amsoil ATF, 7" touchscreen Android powered stereo (direct from China) w/ 4G LTE mobile data for streaming Netflix, HBO GO, Slingbox, Pandora, etc.

I had a similar thud and it was because the rear u joint of the rear shaft was bad.

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2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs

It's chiny! One less rusty piece of steel on my CRD.




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2006 Jeep Liberty Limited CRD (purchased 10/30/12 w/ 52k miles) GDE HotTune & Eco TCU, Suncoast TC, Amsoil Full SAPS (EFM) 5w40, Amsoil ATF, 7" touchscreen Android powered stereo (direct from China) w/ 4G LTE mobile data for streaming Netflix, HBO GO, Slingbox, Pandora, etc.

I had my jeep in the dealership for the trailer hitch recall and had them look at the driveline them clam to have had "several techs" look at it and find no issues with it. The lash is very noticed it jerks you a bit when it happens... I will be pick it up today and giving them a piece of my mind.

I had my noise for like a year and looked at the u-joints on the rear drive shaft a bunch of times and never saw a thing. I even pulled the front shaft to rule it out since the rear shaft looked fine. It wasnt until I went and changed my oil 2 or 3 weeks ago and decided to take another look that it was apparent the rear u-joint was about to come apart. You may be in the same situation.

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2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs