Ok, so I've got this vibration on my KJ from 45-50 and only when I push the accelerator, this vibration comes from the rear end. If I coast or anything but not push the accelerator I don't get any noises. I replied to a topic about a similar thing in the 4x4 discussion and I wanted to bring it out here so more (non 4x4 people) might be more likely to see it and respond.
I have an '05 KJ Renegade with about 1500 miles on it. It's got the command trac 4wd system, and the off road package (main thing out of here that might make a noise like this is the limited slip diff).
I took it to the dealer today, and after having it for 3hrs they called me and told me it was ready to pick up. Well I head down there cause I couldn't get ahold of the mechanic, and when I get there he tells me nothing is wrong. Says that they looked at the rear end and test drove it. After I asked, he looked in the computer and confirmed that they also checked the wheele balance. On the invoice they stated this;
"Verified slight vibration when driving at about 45mph. There is no abnormal noise coming from rear. Road tested another liberty with same options and the other liberty does the exact same thing. Checked techconnect for any tsb's that may relate to this concern, none found. This is the normal characteristics of the jeep liberty."
I'd like to make a comment about the other libby they might have tested, I bought my KJ on July 12 and it was the last 2005 4x4 they had. I assume it's possible in that time that they might have got more, but this whole DC dealership is split between 4 lots and the lot that they told me that does recieving (the lot I got my KJ at) is a good 20miles away. So my guess is they took a 4x2 KJ that has an auto and v6 in it. That's probably as close to "same options" as they got.
What I'm wondering is this. Is this a normal sound that most people hear with their libbys? Specifically '05 Stock 4x4 libbys? Or any model years for that matter. What do those of you who have more practical experience with the mechanics of automobiles think? To me this sound doesn't sound like normal road noise, even for a truck. Now I've never had a jeep before, but I've driven in trucks and rwd vehicles that had bad rear diffs. Only the ones with bad rear diffs made any sort of vibration in the rear end. And it's not like the tread on the goodyears are that agressive to cause this noise. Besides it's only when I push the accelerator.
My biggest worry is when I find time and get the things I need together and finally do take it off road, well, I don't want it to break lol. Last thing I want is it to break and the dealer to tell me it's not covered. Also I plan to get the Frankenlift for it, but I don't want to do anything til this is resolved for similar reasons.
One nice thing the dealership did for me was pay for my rental car after I told them to
Thanks,
Justin