Gear whine on coasting after regear to 4.88s. Shop is claiming its a "driver comfort issue" and that it's normal. This can't be normal.

[chevymitchell]

I just did a regear to 5.13 for my 2021 JLUR last week. Everything is ok except that when coasting between 8-10 mph I can clearly hear the gear rotational humming sound. Is this something I need to address immediately and can wait till 500 mile checkup to resolve? @chevymitchell , any suggestions? Everyone's answer and especially yours have been super helpful, thank you all!

It needs to be fixed immediately. You don't want to break-in a new set of gears wrong. If you wait until 500 miles and then correct it, you may have machined a face into the teeth where the gears will forever hum until you replace them.

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[hardrock_sea]

It needs to be fixed immediately. You don't want to break-in a new set of gears wrong. If you wait until 500 miles and then correct it, you may have machined a face into the teeth where the gears will forever hum until you replace them.

Thanks so much for the quick answer! I will give the shop a call tomorrow!

 

[chevymitchell]

Thanks so much for the quick answer! I will give the shop a call tomorrow!

You're welcome, man. 5.13's are the toughest set to get right in these Gen III's, but can be done without issue. Just takes some adjustment. I'm sure the shop will be happy to correct it. (They should be, anyway.)

 

[hardrock_sea]

You're welcome, man. 5.13's are the toughest set to get right in these Gen III's, but can be done without issue. Just takes some adjustment. I'm sure the shop will be happy to correct it. (They should be, anyway.)

I was debating to go with 4.88 or 5.13, and the shop strongly recommended 5.13 with my set up and mountain pass driving. I didn't see a huge torque gain since I am taking it easy during break-in, but I did notice 1-2 MPG improvement for local driving.

BTW, does the humming impact anything? Does it cause the parts to fail prematurely? For me, it only happens when letting the foot off the gas pedal and coming to a stop and only in the 8-10 MPH range.

 

[chevymitchell]

I was debating to go with 4.88 or 5.13, and the shop strongly recommended 5.13 with my set up and mountain pass driving. I didn't see a huge torque gain since I am taking it easy during break-in, but I did notice 1-2 MPG improvement for local driving.

BTW, does the humming impact anything? Does it cause the parts to fail prematurely? For me, it only happens when letting the foot off the gas pedal and coming to a stop and only in the 8-10 MPH range.

The humming is the gears reaching a harmonic you can hear. They always hum, but the audible harmonic is when the teeth aren't meshed properly. Usually, you can feel this in the seat and steering wheel, as well.

It's not going to grenade the gears, but any audible harmonic like this is building unnecessary heat. You'll be fine driving them like that, but I would drive it as little as possible. You really don't want to start chipping the end of the teeth off.

 

[CarbonSteel]

You're welcome, man. 5.13's are the toughest set to get right in these Gen III's, but can be done without issue. Just takes some adjustment. I'm sure the shop will be happy to correct it. (They should be, anyway.)

Unless it's you doing it! A year later and my 5.13's are still perfect!!

 

[chevymitchell]

Unless it's you doing it! A year later and my 5.13's are still perfect!!

Lol. Not everyone is willing to drive as far as you did, that's for sure.

 

[hardrock_sea]

The humming is the gears reaching a harmonic you can hear. They always hum, but the audible harmonic is when the teeth aren't meshed properly. Usually, you can feel this in the seat and steering wheel, as well.

It's not going to grenade the gears, but any audible harmonic like this is building unnecessary heat. You'll be fine driving them like that, but I would drive it as little as possible. You really don't want to start chipping the end of the teeth off.

@chevymitchell , I recorded a video below to show the noise. It can be heard at 5" and 10" with 5 and 4 clicks of noise respectively. Can you confirm help it is the same whining/humming issue being talked about here? Thanks!

 

[Map08008]

I just had my gears done at a shop and I asked for all parts back but only got the ring and pinion gear back none of the bearings or shims… I called the next morning to ask why and they said they had tossed those in a barrel with a bunch of other parts and it would be too hard to find.. should I be concerned?

I have no proof they actually used the new parts kit. I also have a quiet whine, much quieter than the original video but it is there at 20-5 mph on the deceleration side, 30-45 in acceleration side and at 50 under acceleration. Shop wants to address the noise at the 500 mile inspection.

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