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Discussion Starter · #1 ·
Just left the dealership this morning to have them diagnose the grinding / vibration that happens only between 20 and 30 mph. I have had other dealerships look at this and they don't know what is wrong. I looked around and found what they tell me is a certified srt mechanic. We took it for a test drive and he said that it sounds like the viscus cups are bad in the transfer case. He then took it into the bay and about a half an hour later they called me back and said your transfer case is bad. Handed me a estimate for $3600. Said that he looked at the fluid and seen metal flakes inside the fluid. This problem has been going on for quite some time now, when I first bought the jeep used it had this problem and first thing I dis was have the fluid changed and when I asked the mechanic which was at another dealership how the fluid looked he said it was pretty clean. I have had the front axle replaced, all the wheel bearings replaced and the flash update for the tsb that was available. My problem is that I don't know if I believe this new mechanic that it is bad. It does not make the noise when it is on the lift, only when on the ground under a load. I don't mind buying a new transfer case buy it will be a builder bill case though but not if I don't have too. It is a 2006 with 106000 miles and bone stock. It drives great just has the vibration/ grinding noise and only at those speeds, its more annoying than anything. So I am asking you guys what you think I should do? Thanks in advance for all your help.

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Marathon Man
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If you disconnect the transfer case motor. Do you still have the noise/vibration?
 

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This question may sound weird but believe me: What tires are you running, brand sizes and wear?
 

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Discussion Starter · #5 ·
i have stock size tires, back are nitto 420 and fronts are wallen or something like that. i know that the back are almost done but the front's are still with alot of tread. but the fronts do have some cupping and make tire noise while driving but it is different than the grinding noise. i was wondering if maybe the tires were the issue. just don't know how the transfer case can be bad when it drives fine and the noise is only at those speeds,
 

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theres a few of us who have had that issue. Actually just emailed someone bout it. Still yet to figure it out. But you can buy a new Tcase from either builder bill or a stock one for $1000 and put it in yourself. Its relatively easy with some basic hand tools. Save yourself $1500 for mods. There's been people who said the coupler from the tranny to the driveshaft was the culprit, then others who said the drive shaft was out of balance. also saw that some said the rear driveshaft was too short. I would pull the driveshafts individually to get a better a diagnosis.
 

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i have stock size tires, back are nitto 420 and fronts are wallen or something like that. i know that the back are almost done but the front's are still with alot of tread. but the fronts do have some cupping and make tire noise while driving but it is different than the grinding noise. i was wondering if maybe the tires were the issue. just don't know how the transfer case can be bad when it drives fine and the noise is only at those speeds,

Could it be possible that your tires are worn beyond spec?? I can't stress enough how important it is to have 4 matching tires on an AWD vehicle.
Different tire manufacturers have different specs for their tires.....Basically, the Nitto tires may say 285/40/20 on the sidewall, but they could be a different overall diameter than the Wallen tires on the front.
Also, you could have 2 different treadwear ratings between the front and rear tires, causing one pair to wear faster than the other.....That could cause them to be within spec when first installed, but then wear out of spec as one pair wears faster.
 

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i have stock size tires, back are nitto 420 and fronts are wallen or something like that. i know that the back are almost done but the front's are still with alot of tread. but the fronts do have some cupping and make tire noise while driving but it is different than the grinding noise. i was wondering if maybe the tires were the issue. just don't know how the transfer case can be bad when it drives fine and the noise is only at those speeds,
Haaaaaaa ha!!

I would try to change the tires ASAP. I had different brands (front vs rear) tires on when I purchased the jeep. It had more thread on the front and less thread on the back and I was having the same issue. I replaced them with brand new tires and BOOM the noise an vibration was gone.

Not 100% sure you will solve your problem, but it's worth a try. The TC is very peaky about this.

Good luck!
 
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i am going to replace all the tires asap. would that cause a noise problem, and or ruin the transfer case??
It is possible. If the difference in overall diameter between the front and rear tires is more than 3%, it will set off the "service 4wd" light and the TC will start to act up. I would think that if you are just below but near 3%, while technically "within spec", you might start to get some vibrations and noises....but may not activate the "service 4wd" light.

If the front tires spin at say 700 revolutions per mile, and the rears at 685 revolutions per mile......think about what the transfer case has to endure.........front drive shaft spinning at one speed, rear drive shaft spinning at a different speed....clutch pack in the middle...........at 100 mph :eek:.

If there is any question about them, then the best place to start is with the tires. If you do the TC, and it was in fact the tires.....guess what will break first......the new transfer case. ;)

As said above, removing the transfer case motor will help you isolate and diagnose the problem.
 

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Discussion Starter · #13 ·
Ok, just set an appointment for Monday morning to have a new set of nitto 420's on the jeep. Then I guess we will see. A builder bill authorized shop is going to take a look at it for me late Feb.

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I had the same grinding noise 20mph and under, had my drive shaft replaced and that did not resolve it. then they checked my TC and it was fried with metal flakes in it. I don't know why or how it got fried, but they replaced the entire thing, including the motor and it resolved it. It took about 4-5 trips to the dealer before they found the issue..they just kept replacing parts until it was found.
 

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Discussion Starter · #15 ·
Thank you everyone for giving me your input I appreciate it. It turns out that I will be having the tires replaced today and will update later today with the outcome.

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Marathon Man
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Let us know the results. But like I said, if you still have the noise after the new tires. Disconnect the transfer case motor and see if you still have the noise.
 

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Discussion Starter · #17 ·
Update!!! All the noise is gone, no vibration. Drives like a dream. Very happy now. Turns out it was the tires all along, I spent countless hours chasing this and you guys helped me and saved me tons of hard earned cash. Thank you all very much.

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Thats great news. Glad it all worked out and was only tires.
 

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Discussion Starter · #20 ·
I really don't think there is shavings in the case, about 2 months ago I changed it and the first mechanic told me it was clean and really Didnt need changing, I plan on taking it back to him seeing how he was honest with me and told me I don't know what is wrong and have him change it again and keep it in a different container so I can see for myself. But for right now it drives like a dream!! I love it.

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