nmunlin

New guy here, just picked up a 2011 JKU sport with ~72k miles. Did a test drive, smooth ride, manual transmission shifted almost as smooth as the car I traded in. Haven't heard any abnormal noises before today (bought it Saturday), but my son asked me to pick him up from school with the doors off (hard to not comply with that request).

When driving I'm absolutely assuming I'm going to hear a lot more mechanical noises with the doors off, but I noticed that when in third gear especially, and right at 2k rpm, there is a very noticeable rattle from what I assume is the transmission. It goes away immediately if I press the throttle, and I haven't really been able to replicate it in any other gear. It's not the same rattle as the shift knob, I noticed that during the test drive but wasn't gonna let that deter me. When I first noticed the noise I thought maybe it was too low rpms for the gear but then when I heard it the second time I saw I was right at 2k.

I had a similar symptom on the car I traded in and it ended up being the injectors, but in the car, once I heard the noise, the rough ride and stalling started soon after. I have been riding around today with no other issues. Has anyone had any similar experience? Im sure I'll have to take it in, kinda glad I got the warranty for it, if it pays...

Mark Doiron

It could be the heat shield on the catalytic converter crossover. There are several welds along it that can break and cause a slight rattle. Other than being annoying, nothing to worry about. The metal is very thin, so re-welding it can be tricky. Some folks use a pipe or hose clamp to stop the noise. This thread has more discussion about this potential problem. It has a picture that I stole to add an arrow pointing to one of the problem welds ...

https://www.jk-forum.com/forums/stoc...-fixed-169410/


One of several welds to check on the catalytic converter crossover heat shield. A broken weld can cause an annoying rattle.

nmunlin

I looked at every heat shield I could find, none were missing bolts or loose. One under the driver door side was able to be knocked back and forth if I tapped it hard enough

nmunlin

So just wanted to give an update

Had a friend who is a mechanic come listen to my jeep so he could hear the rattle. His words "that's definitely not a heat shield." He recommended taking it to a shop and having them diagnose it since he doesn't deal with warranties. And he thought it could be a lifter or a rod bearing.

Fast forward to today, over 7 weeks later, and I have my jeep back home with a reman motor and new clutch. Diagnosis was a rod bearing. Once they got to that point of failure, the warranty company ordered a motor. Company claimed 12-16 days; vastly incorrect.

Anyway, just thought I'd share. What I thought was a rattle from the transmission, and was then thought to be a heat shield, turned out to be the rod bearings at minimum.

MikeInMiami

I'd say the warranty has payed for itself!!! Awesome!!!

nmunlin

You have no idea how bad my anxiety was when I found out what was wrong and then waiting to see what the warranty decided