thrumming vibration

[AnmiP]

Nice thing is that the sales guy and the service advisors where I've been going know I'm a former mechanic/tech myself and still have a shop doing restorations.
So they actually look at the diagnostics I give them, the freeze frames of engine misfires, and the details of a misfire on a different Jeep that let them right to a STAR case that matched my symptoms exactly (and thus it was fixed before a TSB was released).
Otherwise, some will think "just another customer telling us how to do our jobs".
Building a relationship with the people there has really mattered. It's also gotten some freebies and work done they'd normally never do.
A lot depends on the people and their attitudes - some will resist, others will say "let me look at that".
My next visits will be a bit more tricky - JLU with transmission leak for the 2nd time - suggesting "I don't believe it's the pan gasket, please check higher" (based on dozens of others with the same leak in the same place and the fix was a new transmission) and my JT - shocks and a weird clunk only under very specific conditions - oddly, I've not found that one myself and it's a really new one I've never heard before. I will keep trying to find it but.......

I guess, and this is just me - I'd put hose clamps on the driveshaft to see if it changed the vibration in any way at all - ANY change, in frequency, volume or intensity, any change at all. No change, barking up wrong tree. ANY change, it's a suggestion that it may be the right direction.

Outstanding recommendations, thanks. Especially the building rapport with the service staff. I forget that on occasion, and usually pay the price for neglecting that part. Hose clamps, will do!

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[AnmiP]

Update, kinda:
Since my previous posts, the thrumming / vibration started getting worse. On a positive note, this prevented service techs from claiming it was "operating as designed."

Have been working with Jeep Cares, the Customer retention team, and another dealer. They agreed the vibration is not normal and set to work trying to figure it out. Over a month later after replacing transfer case and the driveshaft, they said I can pick it up, it has been fixed! ? Unfortunately, some vibration remains .

Notably, the service dudes said the output shaft of the transfer case had excessive runout, and the driveshaft center bearing was loose/worn out (I checked the torque on the center bearing bolts myself, so I presume "loose" is referring to the degrading rubber around the bearing). This is at approx 5800 miles on the JT.

After driving 120 miles following the repair, the vibration seems to have subjectively improved (new parts needed broke in I guess). The sound app I used previously still shows a spike in noise between 55-65 mph (57mph), at 40hz; though the overall spectrum seem to have smoothed out a bit.

Summary of everything so far:
Total of approximately 150 days at two dealerships, multiple Jeep Cares & retention representatives, new tires, wheel swaps, new transfer case, new driveshaft, suspension bolts/nuts retorqued, and replaced engine (not vibration related).

I'm not sure if the vibration that remains is a toned down of the original, or with the thrumming reduced I am now aware of other noises. Either way it is disappointing that a new vehicle required a large part of it's drivetrain replaced and 150 days to do so.

 

[AnmiP]

Update, kinda:
Since my previous posts, the thrumming / vibration started getting worse. On a positive note, this prevented service techs from claiming it was "operating as designed."

Have been working with Jeep Cares, the Customer retention team, and another dealer. They agreed the vibration is not normal and set to work trying to figure it out. Over a month later after replacing transfer case and the driveshaft, they said I can pick it up, it has been fixed! ? Unfortunately, some vibration remains .

Notably, the service dudes said the output shaft of the transfer case had excessive runout, and the driveshaft center bearing was loose/worn out (I checked the torque on the center bearing bolts myself, so I presume "loose" is referring to the degrading rubber around the bearing). This is at approx 5800 miles on the JT.

After driving 120 miles following the repair, the vibration seems to have subjectively improved (new parts needed broke in I guess). The sound app I used previously still shows a spike in noise between 55-65 mph (57mph), at 40hz; though the overall spectrum seem to have smoothed out a bit.

Summary of everything so far:
Total of approximately 150 days at two dealerships, multiple Jeep Cares & retention representatives, new tires, wheel swaps, new transfer case, new driveshaft, suspension bolts/nuts retorqued, and replaced engine (not vibration related).

I'm not sure if the vibration that remains is a toned down of the original, or with the thrumming reduced I am now aware of other noises. Either way it is disappointing that a new vehicle required a large part of it's drivetrain replaced and 150 days to do so.

So just when you think you're done with it all...
After driving less than 200 miles I was disheartened to discover, you guessed it, a vibration at highway speeds most prominent at 57mph. Ugh. For anyone still with similar issues, here is where I'm at.

Replaced so far:
Tires, transfer case, driveshaft. (& Engine, unrelated to this issue)
Tires made no difference. Transfer case & driveshaft replaced; temporary improvement, vibration is reduced and is now constant, not a thrumming/ rhythmic noise.

I decided to take a look at the rear axle, since it is the only part remaining in the chain not replaced, and found two items of note. One: removed diff fill bolt and discovered about 1/3 -1/2 inch blob of metal fines on the magnet! I'm guessing that is not normal at 6400 miles of use. Two: put vehicle in neutral (level ground and wheels chocked) grabbed the driveshaft and twisted it back and forth. There is a good approximately 1/3 inch rotational movement of the driveshaft & pinion with no movement of the axles. I am also guessing this is not normal at 6400 miles (my 2007 JK Rubicon w/230,000+ miles & original axle doesn't do this), may be why the vibration is increasing noticable, and seems to be spreading to other speed ranges (still worst at 57mph). In my shadetree mechanic knowledge I would presume this would imply incorrect pinion setup, which lead to deterioration of other parts.

I wish I could say "eureka!", get it fixed an move on with my life, if only it was that simple. Since the Mojave has spent over 150 days at dealers so far, and 6 week waiting was the quickest service appointment Jeep Cares could arrange within a one hour driving radius last time, the vehicle downtime is conflicting with my employment/ livelyhood and sanity. Since corporate cannot provide "compensation" until all problems are resolved this Jeep has become an unsustainable financial and time burden to my family. It appears that a buyback is my only viable option.

I will note if the problem is ever repaired, FCA said they would be able to provide compensation of $5000 maximum (up from $2000 initial) "no negotiation" for my inconvenience, which does not cover the financial burden this has caused my family (especially since no rental was ever provided, and loaner request were denied by the dealers).

It is a with a sad heart that I find myself looking to move on from the Jeep brand after 43 years of being a Jeep guy. For what it is worth, in the short time I had the Mojave in my possession, my family grew quite attached to it despite its defects. We just can't stomach the cost of it sitting at a dealer all the time, can't enjoy road trips with the vibration, and can't justify the 10%+ MSRP increase since we bought our lemon just over a year ago.

Thanks for letting me vent, and I hope no one else has to go through the experience I and my family have.

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