Jeep Whining when letting off the gas

[JTRUBI]

A little background about my Jeep. I picked up my factory ordered 2020 Jeep Gladiator Rubicon with a 6 speed manual on July 22nd 2020. I drive a lot. As of today I’ve put 6,200kms on the Jeep in just over one month. It is bone stock, less a couple cosmetic options, but it’s stock wheels, tires, suspension, exhaust, intake, tuning, etc. I typically drive my Jeep just to work and back but I’ve done a couple road trips on the weekend but that’s really it.
It has never been off-road, never been in 4wd.
Yesterday heading home from work I noticed a whining noise when I let off the gas. It doesn’t matter which gear I’m in or at what speed I’m at it but it does it. I’m going to have my service department take a look at it on Monday but wanted to see if anyone had experienced something similar.

I have a couple possibilities I’m thinking it could be in my head but I wanted to see what everyone thinks before I stress too much.
Any thoughts of what it could be ?
Again it’s a bone stock 2020 Gladiator Rubicon 6 speed manual that has never been off-road or even in 4wd yet.

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[JTRUBI]

Any thoughts guys ?

 

[MLWYATT]

I have a noise on the drivers side front that I hear when decelerating. Sounds like engine braking and I can’t fully tell if it goes away fully when I put the trans (auto) in neutral. New Sport S Max Tow with less than 500 miles. Dealer will diagnose when my steering box comes in and they replace that. I took it in last week but they wanted to keep it and call “Star” to help figure out what it was or to do it when they had it to fix steering so I decided to wait and do it all at once. I don’t even think they drove it when I took it in as they were super busy. Please let me know if you figure out what is up with yours and I will do the same.

 

[Tornado_6]

Pinging this thread to see if you guys ever figured out the noise. My 2021 JT Overland makes an "engine braking" noise when I take my foot off the gas. It's a little subtle, but I hear it and never had any issues before January. This started suddenly and correlates with emails from Jeep Service stating that I have a Malfunction Indicator Light triggered alert for Powertrain. There are no warning lights on the dashboard. I have had two different dealers check it out, and both said there are no codes in the computer.

I feel like the noise and the emails are related. How should I go about trying to get this resolved? Keep shopping around for a service department that will do more than a cursory check? Go to an independent repair shop? Try to elevate it to corporate?

 

[DocGladiator]

My 21 mojave manual trans has the same whine when I let off the gas. The noise is there whether I’m in gear or coasting. Whine goes away when I’m on the power and accelerating. Sounds like it’s coming from under the back of the truck.

I just cracked 10k miles on it. Had it since new.

Any updates on this?

 

[Tornado_6]

Mine with automatic transmission (17K miles) is still doing it. I have not gotten any MIL emails in months, so whatever was tripping that flag seems to have fixed itself. I put on a soft top for the summer and the noise didn't bother me. Now that it's winter with the hard top on, it's a lot more noticeable. It might possibly be louder now than when it started, but I don't have an objective way to measure that, so it's hard to tell if it's correlated with outside temperature.

I have had one dealer say "What noise?" (like they couldn't hear it), and another try to convince me it is tire noise (stock Overland tires, but the noise only occurs when letting off the gas).

At this point I'm hoping it gets a lot worse during the warranty period so I can get it fixed on their dime. The hard part for me is convincing someone to take my concern seriously.

 

[JTDay]

My 6MT whines a bit, most audibly in 5th and 6th gear, accelerating or decelerating. I'm not concerned about it at all tbh.

 

[AHenry014]

A noise that goes away under power and occurs when on decel is usually either differential gear noise or tranmission noise. The diff could be improperly set up from the factory, broke in and is now out of spec, poor lubrication, etc. Trans, if MT, could be "part of the experience", if AT, who knows. I occasionally hear mine make whining noise, but is nowhere near loud enough for me to be worried.

In any event, if you are still under warranty, bring it in and have them check it out. If all is "fine" then at least its on record. If one was to have a serious issue after warranty period, you could potentially make an arguement that it was "known" and you attempted to have it repaired under warranty. Could save some money there or have it taken care of in good faith.

 

[ShadowsPapa]

I have had one dealer say "What noise?" (like they couldn't hear it), and another try to convince me it is tire noise (stock Overland tires, but the noise only occurs when letting off the gas).

Some noise is normal and expected. DEPENDING on the cut and shape of the differential gears, some may be a lot worse than others on the coast side of the gears.
Fords, for example, have a steeper cut gear for strength and quiet on the road side but it makes them weaker and more prone to noise on the coast side.

If the sound changes dependent on the gear you are in, then it's transmission. The differential - ring and pinion, won't care about what gear it's in. Only load and speed.

As said, if there's concern, take it in, make sure they write it up. Even if they say "no problem" it's on record if it gets worse.

One could also change differential fluids if they are so inclined, and use a quality fluid (personally, for this I'd stick with the stock stuff because some of the aftermarket stuff is crap for extreme pressures of hypoid gears and there's been some pinion bearing failures after changing to another brand fluid (who knows the cause!)

 

[jac04]

I remember reading something about the double-row ball pinion bearing on the new Advantek axles producing more noise than previous generation tapered roller bearing arrangement. Even if that is the case, if the bearings are properly set up, any noise should remain constant with road speed and should not change when on/off throttle.

 

[ShadowsPapa]

I remember reading something about the double-row ball pinion bearing on the new Advantek axles producing more noise than previous generation tapered roller bearing arrangement. Even if that is the case, if the bearings are properly set up, any noise should remain constant with road speed and should not change when on/off throttle.

Bearing noise can change because of the thrust on the pinion.
Thrust is either forward on the pinion, pushing it out, or rearward, pulling it in, depending on the direction of rotation. A noisy pinion bearing can be more or less noisy under load, depending on if it's the front or rear bearing.

So moving the truck forward, the rear or inside pinion bearing is the thrust bearing. In reverse, the front or outside bearing is the thrust.

 

[jac04]

Bearing noise can change because of the thrust on the pinion.

I deal with industrial gear drives on a regular basis and completely understand the loads generated by the gearing. The reason for the bearing preload is to minimize the variation in loads, essentially minimizing fatigue and transient load conditions. So, like I said, if the bearing inherently makes more noise when set up with the proper preload, it should remain constant with road speed and should not change when on/off throttle. The only time you should have variations in noise is if the preload isn't correct.

 

[ShadowsPapa]

On a differential under the load of the hypoid gears, you can have more thrust against a bearing than the preload presents.
It's not an uncommon theme out there.
And with the double-ball front bearing, I have a feeling there's more issues with these than other drive systems.
Guys that flip differentials and use them on the other end, etc. have found out how it can end up.

 

[DocGladiator]

My dealership confirmed that the noise was coming from the rear diff and promptly offered to replace the whole rear axle! Love that Jeep is taking care of us, but I didn’t want to go that route because I don’t want to go back to the stock gear ratio.

Brought it back to the shop where the re-gear was done. They’ve confirmed it’s premature wear on the pinion bearing.

I just authorized them to do the work. I’ll let you know how it turns out when I pick up the truck.

 

[jac04]

My dealership confirmed that the noise was coming from the rear diff and promptly offered to replace the whole rear axle! Love that Jeep is taking care of us, but I didn’t want to go that route because I don’t want to go back to the stock gear ratio.

Are you saying that your dealership knew that the axle had been re-geared, but still offered to replace it under warranty? Never heard of that before.

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