Emrah

We just bought an '06 3.7L Grand Cherokee used with 134K miles. All's good except a strange "rumble strip" noise that will intermittently come and go. It happens at all speeds. It literally sounds exactly ike you are driving over rumble strips.

I've done several hours of Google searches on this, and it seems people have similar symptoms, but never follow up on forums after getting advice, so I don't know if they ever fixed it and what it was. I can't imagine it's the driveshafts or U-joints, as it only does it on and off.

The strange thing is, when the vibes start, I can ever so slightly "bump" or tap the throttle and it goes away; at least for bit, then comes back. But the tapping of the throttle is not enough to load/unload the driveline. The vibes stop IMMEDIATELY upon barely tapping the throttle. Not enough time to apply torque or accelerate.

It had the check engine light on, for a day, but today, it was gone. We just bought the truck a few days ago and I haven't had a chance to scan the code.

Any ideas what this could be? I've read everything from U-joints to bearings to torque converter.

Stumped.

Emrah

dave1123

I don't know specificaly what it is, but check your engine cooling fan. An out of balance fan can cause a noise similar to what you are describing. A bad fan coupling or clutch or an electric fan with a chunk out of a blade can cause a lot of vibration.

My 00 WJ has an electric fan and sitting at idle, I can tell when it's running. There is a very slight harmonic vibration in the entire car.

How violent is your noise? Does it shake the whole vehicle or is it just annoying? It sounds to me that it's not in the driveline because it appears at any speed or throttle setting. Tapping the throttle changing it is a mystery.

Emrah

Well, I did some testing and I'm convinced it's the torque converter. Driving down the freeway, if I leave it in "D" and it clicks into overdrive, it rumbles and chatters. As soon as I manually put it in "4" (not overdrive) it stops. No sound for miles.

It also does it at surface-street speeds. If I keep it in a gear lower than it "should" be in, and the revs above approx. 2000 rpm, then it doesn't do it. For example, if it "wants" to be in 4th gear at say 40 mph, then it will make the rumble strip noise. If I manually put it in 3rd gear, then it stops.

I think it's the TC clutch that's trying to engage but is fried. Oh, and I go to check the tranny fluid (mostly to see and smell it) and there's no freakin' dipstick. Just a cap saying "Dealer Use Only". Unbelievable.

Waiting for our extended warranty info to be faxed/overnighted over to the warranty company ASAP so I can take it in to a shop and have them do the repair (which, according to my paperwork, is covered).

Pissed.

Emrah

ashleymckinney

Did you ever figure exactly what it was? My 06 is doing the exact same thing.