Rear Diff and Active Spoiler Issues

I know some of you have posted about having your rear differentials replaced under warranty in the thread below, but I think this issue deserves its own thread, as I believe this is a more widespread issue than we know about or that Toyota is letting on about.

https://www.tundras.com/threads/whistle-above-65-mph-not-wind-noise.125509/page-3

Long story short, about a month ago I started hearing a drone/hum under acceleration at around 70-75 mph. At first, I thought it was just tire/highway noise from the highway I frequently travel, but the more I traveled with the truck, the more the noise became apparent. I took it in for service (I already had an appointment for them to look at a variety of QC issues), and I asked them to take a look at the rear differential. At first, they tried telling me it was most likely the tires. However, I kept insisting that their master mechanic inspect the rear diff, and sure enough, he found metal shavings in the diff fluid/oil and recommended replacing the rear differential.

Apparently, the service department and Toyota went back and forth on whether or not my vehicle is safe to drive while they wait for replacement parts. Toyota told the service manager that it’s their call to make, and the master mechanic basically told them it’s their manufactured part and that they should make the call. Anyway, I ended up taking my truck because I needed it, and so far It doesn’t seem like it’s gotten worse. Hopefully it doesn’t lock up on me.

Now, why I think that this is a more widespread issue is because I’ve since talked to several 3rd gen owners and many of them mentioned that their trucks make the same noise. Some noticed it after speaking to me, others have noticed it but thought it was road/tire noise, and others have been going back and forth with their service department. If your truck is making this noise, take your truck in for service, and have them inspect the rear differential!

Additionally, the front active spoiler on my truck was squealing (almost sounded like brakes whining) every time it retracted right around 25 mph. It had a bad motor that was also replaced under warranty. My truck doesn’t yet have 5k miles, and it’s had these two mechanical issues and a variety of quality control issues as well. 3rd year into production, and you would think Toyota would sort this stuff out. Small squeaks and rattles I can understand, but having a rear diff replaced before its first oil change is more than disappointing.

 

Hmmmm. There will usually be some metal shavings in the diff at first fluid change, not sure that is definitive for failure. The hum could be located with an automotive stethoscope to determine if one of the bearings is the issue.

 

Toyota green lit the differential replacement under warranty, so there’s definitely something they found that warranted the replacement. I’m still waiting for a detailed explanation.

 

Mine was more than a few shavings and the gear oil was black and smelled like it was burnt. When I first suspected the diff, I drove on a very smooth road with the window down and could hear diff whine get much louder than the wheels as I accelerated. Finally, mine was so bad, Toyota didn't want me to drive it and gave me a loaner car. I am scheduled to take my truck in for first service in June and they will change the diff gear oil again to make sure it's holding up. So far, no whine after 500 miles.

UPDATE: Well, it's June and time for a check up on the diff. Had the same Master Mechanic change the diff fluid who replaced my truck's differential. Wanted him to do the inspect and change since he knew what the previous mess looked like. Happy to report no discoloration or issues. All is well and since replacing my tires with Michelin, she's very quiet and smooth. Had my first oil and filter change today too. 2,507 miles.

 

Whine sounds like gear problems. Hum sounds like bearing issues.

 

The hum sound is only noticeable when accelerator pedal is pressed. If it was bearing issues, hum noise would be there either accelerator pedal was pressed or not

 

Thank you for the heads up on both of your issues!....Yeah both of them or not good to have to deal with at only 5K miles....And you are right, Haven't heard much on rear diff issues.....Kind of like I had a new transfer case replaced at 7K, noise started at 500 miles on the ODO.
New Transfer Case @ 7K miles.... | Toyota Tundra Forum (tundras.com)

 

I just read your post on the transfer case. It’s criminal that they took 7 months to admit there was something wrong with the truck and ultimately fix it. I’m certain I would’ve experience something similar had I not already opened a case with Toyota for other issues. I’m starting to feel like I’m driving a ticking time bomb…

 

40k on my ‘22 and I just replaced the 3 diff fluids. Front ,rear, and transfer case. No sound previously, nothing afterwards, and no leaks. It was pricey.

 

I just got a call that my rear diff replacement is in, so I’ll be taking the truck back tomorrow. Maybe I can get them to throw in a maintenance plan for my troubles. How much did you drop on the fluid replacement?