hey guys/girls, so im new here and new to jeep... i bought a 07 liberty 3.7L 4x4 with 106000 mi on it, great shape, not a spec of dirt on it... in fact it looked brand new..at least when i saw it i thought it was its that clean in and out... anyhow, runs like a champ except at 30-35mph and about 1500-1700 rpm it stutters...the whole car shakes... feels like im driving over rumble strips... im no dummy when it comes to mechanics.. iv been one for 6 yrs in the powersports industry... so the auto industry is a slight bit different but yet things operate the same with different names...anyhow... at first i thought spark plugs are doo doo since it has 106kmi on it. so i put new ones in it, NGK brand and the recommended version as per the local jeep dealer...gapped to .042"... test rode it, same thing...no change... then i was thinking it had bad coil packs... so i bought all new ones ( was gonna do it anyways, just needed an excuse )... still no dice, same issue... i dont have a engine MIL on nor a Trans MIL on... i hooked it to my OBD2 scanner and there was no stored codes, and all the sensors i tested passed even when it was stuttering according to the readings and graph output...so now im thinking mechanical issue...also, more recently, when in Drive, foot on the brake, everything seems fine till i let off the brake slightly, enough to let it barely creep forward, however it doesnt creep exactly, it pulsates forward...

questions
1: what should i be worried about with these rigs?
2: has anyone had these issues before?
3: do they have a really tall stall converter?

Sounds like TC shudder to me. I would have serviced it as soon as I got it, but if you haven't, first thing I'd do is service the tranny. No flush just a pan drop and screen/filter replacement. See what the fluid and pan residue looks like. Wonder if someone used something other than ATF+4?? If you suspect the wrong fluid then I'd chance a flush with the correct ATF+4. There are additives to help add frictions modifiers as a temporary solution. Lubegard makes one:

http://www.amazon.com/Lubegard-19610-Tr ... B0002JMLQU

_________________
02 Limited 179K (GONE)
05 Limited 71K (DD)
Lots to do... too little time.

thanks 02blue..

i was planning on getting into the trans next to svc it anyhow...

Although the 07 and 08 have different body styles, they share the same power train including the electronics which were new in 07. I remember there being a Technical Service Bulletin for the 08 about this very issue. The dealer can reflash the TCM to adjust the shift points, thereby eliminating the problem. There may not be anything mechanically wrong at all if this is the case.

_________________
2008 Liberty Sport 4x4 Automatic

Jeepin By Al 4" Lift Kit
BFG KO2’s 245/75R16
Full MOPAR skid plates
Rock Lizard Skink Super Sliders
AtTheHelm Front Recovery System & Roof Rack
M116A3 Trailer build thread: viewtopic.php?f=72&t=77997

Good point! I remember this one for later models. Didn't realize it included the 07s too but looks like it did cover them:

http://www.jeepproblems.com/tsbs/Liberty/2007/

Still would be a good idea to check/change the tranny fluid if you haven't.

_________________
02 Limited 179K (GONE)
05 Limited 71K (DD)
Lots to do... too little time.

thanks guys... ill have to look into the tsb about the torque converter shudder...and the shift point reprogramming...im curious if thats my issue...i noticed today that the trans doesnt like to upshift when the load is increased... you have to mash the pedal to get it to realize it needs to shift...could be a combo of the two...

interesting...