I have a 2004 Jeep Unlimited with 20,000 miles, still under warranty. Consistently at about 45mph while in O/D there is a buzzing, rumble, almiost like you are driving on the rumble strip on the edge of the road until about 60mph. The dealer has replaced the entire o/d gear set and the torque converter as well as the front pump on the transmission. Finally they drove another wrangler and determined that this was normal. Does anyone else experience his sound/vibration? The sound goes away when o/d off switch is turned off. Thanks.

Well, I can't offer direct help but my new 06 Rubicon auto is a lil' tiny bit noisy at idle, just a slight-almost rattle that I'm sure is trans related. No strange noises or sensations of any kind while in motion at any speed, at least not yet.

I've got a lot of vehicles and am real, probably overly sensitive to rattles and vibrations. It's clear that Jeep did not go, nor perhaps could they, to extreme lengths to isolate all NVH from the drivetrain. It is an offroad vehicle so I suppose the standards are different.

A buddy of mine and I both bought the exact same model GM 4x4 truck a few years back, his was super tight and smooth, mine had a rattle in the trans that never was fully corrected even after two new torque converters and other tweaks. Later, they said it was "tolerance stack up" that sometimes "just happens" with mechanical devices, especially 4x4's. I drove it for 65K miles with no problems but hated the sound/sensation.

It sounds like something is for sure wrong with yours...they did after all replace a bunch of stuff initially but now can't or won't mess with it anymore hence they say it's "normal." Very irritating. Maybe another dealer will be willing to try again. Also, I'm learning that there are fewer and fewer real mechanics out there, who can properly diagnose problems. A lot of "plug and play" folks wrenching on cars these days.

Good luck and keep us auto trans guys informed of what you learn!