ssramage

Been running a TF 2.5" coil lift with Rancho 9000s for about a month now. I also have Rancho LCA brackets and a Rock Krawler track bar installed. I have also installed Grade 8 bolts throughout the front and have torques everything to spec.

I've noticed that I randomly get a thump/clunk under the drivers floorboard when running at highway speeds (60mph), never at lower speeds. I've crawled all around under the Jeep and don't notice anything major off, but maybe I'm missing something?

My original thought was the inner fender well is loose and could be slapping, but sometimes this clunk is enough that passengers have felt.

What could be going on? What should I check?

NJKURPat

I've noticed this as well. So I'm gonna keep an eye out on this thread. So far my only idea is the hood flutter is felt in the floor.

judesign

I know some have experienced steering shaft clunking and there are some threads on it here. Also with switching hardware away from original bolts can wallow out factory bushings in things like control arms and track bars so even if it's torqued it could be slapping around a smashed bushing.
In the past I've taken the doors off and drove around with someone while we both listen for the sound and try to pinpoint where it's coming from.

May have already done this but I would also check ball joints and u joints both drive shaft and axle for play.

Long post I know but I've had to do all of this crap before to find an annoying clunk

ssramage

It's actually not an audible clunk from what I can tell, but you can definitely feel it in the floorboard.

I'm hoping it's as simple as the inner fender slapping. It looks a little loose and I trimmed the air dam plastic to fit 35s so there's more air flow. It just didn't become and issue until the lift.

ckor

I believe it is the fenders. They are loosely installed. Mine was slightly noticeable. When I installed mud flaps it became more noticeable. You can grab the mud flaps and shake the whole fender.

ssramage

I'm really hoping that's all it is. I'm going to pull the doors off one day this week and do some riding to see.

I guess it looks like I NEED flat fenders now!

14Sport

Also check your upper shock bolts. One of mine loosened up within a couple of weeks of install. May not be your problem but worth a look.

rikart

I chased this forever on my 2011 JK, I installed a 2.5 lift and 35s and started to fell a clucking under the driver floorboard at highway speeds. Thought it was the fenders but was the foam insulation between the metal heat shields and the floor flopping in the wind. It starts at the the firewall and goes down over the trans and tcase, shot some expanding foam in and few spots and stopped it. Hope this helps.

gburkett

What did you do with your exhaust? If you put in spacers if not just perfect the y pipe will hit the cross member directly under your feet.

ssramage

I actually have not installed the spacers yet. I need to, but there was plenty of room not to need to do it immediately.