Rumble when accelerating. Could it be pinon angles?
 

Hey guys. Could use your input. Ever since installing my 2.5" lift and 35" tires my jeep makes this rumble/studder problem when accelerating hard (from stop, or from low gear rolling). I haven't done a regear yet and am still running the small stock ratio. I've just been gentle with it up until now...today I was stopped at a light and when to accelerate and got the rumble really but, however this time it was accompanied by a strange squeeking sound.

Something strange to note, after I installed the lift I went for a few days without reprogramming with the AEV programmer. The rumble would happen then too, but it would throw a error code of something like "wrong 2nd gear input/output ratio". I can't remember the error code but will track it down. Since doing the reprogram the error doesn't get thrown when the rumble happens.

I've taken some shots of my driveline to see if you guys can notice any obvious issues. I'm thinking that the front shaft angles on the stoke CV might be the cause of this. One thing I've found strange about my lift is that the front sits slightly higher than the rear. I was told that this is normal and is done because Teraflex expects customers to out winches and larger bumpers on the front.


So with all that said, can anyone offer advice with this issue? I'll post a link to some photos for better diagnoses.


Thank you and Happy Thanksgiving,
Bradley

Photos of my Jeep JKU
https://drive.google.com/open?id=0B5...zJjRHliU3F1R2c

Did you install exhaust spacers for cross over pipe . Sometimes the stock front drive shaft can make contact with the cross over pipe
Or brace, if you didn't physically change R&P gears you shouldn't be changing ratio with programmer. Just tire size

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Pinion angle looks good...Definitely not too much for the Rzeppa joints.

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Damn. Think it could be something as serious as my transmission going out? I've read somewhere around the internet that a faulty torque converter can produce similar symptoms as what I've experienced.

What year is the Jeep ? If your still under warranty take it in and have check out...

Manual or Auto?

Just a note, double check the torque on your lug nuts. This happened to my suburban once and that's the same noise I had. Thought a CV was gone but it was the wheel loose!

Any up date..?

Sorry guys, holiday season has kept things busy.

I haven't had a chance to take the Jeep in for a look. I got under and checked the lug nuts, everything looks fine. Next will be to make sure everything with the suspension is torqued.

I feel like it's getting worse in this past week, so thinking of getting it in sooner than later.

It's a 2011 JKU sport automatic

oh, crap, just remembered, my torque converter went out at 90k, sounds like exactly what you have. Just remembered that! check that one out too!

That's what I'm thinking it could be. How can you check that without obviously pulling the tranny?

Hope you get it figured out soon, still have warranty?

It's a 2011 so the warranty is probably expired.

Going to take her by a transmission shop tomorrow to see what they say. I feel like it could be so many things, I'll probably go to multiple shops and see what they all say.

My mechanic deducted it was the torque converter. There was a recall on the TC from 2007-2010. I am thinking some of our 2011s got the bad TCs as well. Mine has been fine ever since. "knock on wood".

Couldn't get it to reoccur by applying the brake and then applying acceleration to 2k rpms. Read somewhere that this might be a way to repro that shudder.

Turn O/D off seems to help a little bit but I can still get it to happen when accelerating.

The shudder is a bit picky. I can only get it to happen when traveling below 10mph and go to accelerate quickly.

From a dead stop on flat I can't get it to reproduce. If there's a bit of an incline then it pops back up. But that's not to say the incline is the only top. It's happened once turning right at a light going downhill.

If I let off the gas slightly it stops rumbling stops.

Someone somewhere mentioned that maybe it's a bad misfire issue. The Jeep definitely doesn't sound the best on a cold start, and does have a slow engine oil leak.

Just an FYI for you and anyone else that may stumble upon this thread.

Try driving around 30-40 mph, and just push the accelerator enough to just to start to accelerate. that's how I replicated.

I had a 2014 JKU and now a 2015 JKU, both had a 3" BDS lift done by the dealer and both Jeeps had this same problem. It happens at slower speeds when I am around 1600-1800 RPm's, it just sounds like a heat shield or something vibrating. I have factory warranty but have just been to lazy to deal with taking it to the dealership and being a couple of days with no car. I have crawled all over the under side and can't find the problem. And I can only some times get it to make the noise while sitting still in drive and getting the RPM's up in that noise range.

I can feel a slight rumble with this method, but nothing to the degree of when accelerating on a hill. I'll try to replicate it and record it.

We're definitely not talking about a heat shield issue here. The entire Jeep rumbles, haha.

Had a pretty rough first startup today after sitting in the cold all night. Wondering if maybe an engine misfire could be occurring.

Here is the update:

Took the Jeep to the transmission shop today. Sounds like it's not the torque converter like I'd expected.

After a few test drives we were able to replicate what the mechanic described as a second gear slip. We were able to find a solid way to replicate the issue and did it a few times. It felt as if it was slipping and then aggressively popping in to gear.

Still questions remain from my side.. Why would there be a slight rumble that happens once I turn overdrive off? Could my troque converter also be going bad along with this 2nd gear slip? And, does the error code P0732 actually mean that 2nd gear is damaged or could this just be and issue of me not having a regear done to my jeep yet?


Based off their suggestion it sounds like the transmission needs to be dropped and inspected($500 to just drop the transmission...).

I think this repair might be something I could just tackle on my own with a few days(excluding parts shipment) of work. Still on the fence as to wether I want to take the time and do it though. If I found out they were wrong and it was something driveline related I would be really frustrated.