My Ioniq 5's Reduction Gear Failed At 64K Miles, Locking Up The Rear Tires, Now The Dealer Says Wait 2 Weeks While I Pay For My Own Rental Car

Before every car was a crossover and Tesla was just a Silicon Valley side hustle, the automotive world ran on a strange fuel mix of badge prestige and tribal loyalties. German marques were the engineers. The Japanese, the reliability gods. And the Koreans? They were the warranty kings. Hyundai and Kia earned headlines for their 10-year/100,000-mile powertrain coverage, a bold play in an industry addicted to fine print. But warranties, like reputations, are only as good as the reality backing them. And for one Ioniq 5 owner, Reddit user kuueon, the limits of that reality came screaming into view when a critical drivetrain component failed just past the halfway mark.

“TL;DR: 64k miles and the Reduction Gear module broke, dealer useless, and I'm stuck paying for a rental until corporate reimburses me. I'm not even sure how it broke unless they just never checked the oil in the thing.

Heading home 6/24 I hear a different noise than I was already used to (I've had some persistent noise from somewhere around the motor anytime I'd accelerate, 10% or 100%, but that's a different complaint) right before the rear tires lock up entirely for a second before unsticking, I pull over, and get out to look around the back of the car thinking something broke, but didn't see anything externally, and nothing was leaking from the motor or gearbox, and none of the half axles were broken....

Ended up limping the thing home with it ticking the whole way, wouldn't go any faster than about 70, and getting an extra nice 2mi/kWh over 30 miles.

6/25 I try and leave for work, tires lock up again while backing up, decide I'm going straight to the dealer so they can't complain they can't recreate the noise. Of course, they don't have any loaners, and all I got offered was an Uber home, sure, whatever.

6/27 they confirmed what I thought it was and tell me they'll have it in 7/1, I ended up renting my own car on Sunday because I needed to get to work (I called a few times about getting a loaner over the weekend, and didn't actually get any response back about it until Monday morning, so, double useless).

7/2 I get a text saying the repair is bigger than they were expecting, and won't be done until next Saturday - I ignore it because I thought this is better addressed in person.

7/3 I go into the dealer and basically get told to call corporate about the reimbursement and fuck off, nothing we can do because all the loaners are still out because your 64k coolant change service was unrelated. So here goes another $300 on top of the $100 I already spent for another rental, plus $550 on service on a car I can't drive and maybe $250 in diagnostics (Still unsure about this because it was deemed in warranty, but who knows at this point).”

The post reads like a slow-motion crash in spreadsheet form, with dates, costs, and a growing sense of exasperation. It started on June 24 with a strange noise during acceleration, something different than the persistent whir the owner had previously reported. Then, without warning, the rear tires locked up. The Ioniq 5 unfroze just as quickly, and kuueon managed to limp the EV home. No fluid leaks, no snapped axles, just an ominous ticking, and poor efficiency. From there, the experience spiraled into a procedural purgatory. The dealership had no loaners, corporate dragged its feet on reimbursement, and kuueon had to pay out of pocket, twice, for rental cars while repairs were scheduled and rescheduled.

Hyundai Ioniq 5 E-GMP Design: Spacious Cabin & Award Styling

• Designed on Hyundai's all-new E‑GMP platform, the Ioniq 5 incorporates “Living Space” architecture, including a flat floor and extended wheelbase, that allows a spacious, convertible interior 
• Designers meticulously refined every detail, like wheel contours and body lines, to enhance aerodynamics and reinforce the EV’s signature futuristic look 
• Hyundai’s brand design team, under a clear vision for its first dedicated electric vehicle, intentionally blurred interior/outdoor boundaries to elevate passenger comfort and usability
• The avant-garde design earned industry recognition: the Ioniq 5 won a TopGear Electric Award for Best Design, reflecting its innovative departure from conventional styling

The heart of the issue is the reduction gear, a component tasked with converting the Ioniq 5’s electric motor speed into something usable for the wheels. It's critical and supposedly low-maintenance. 

Except this one failed at 64,000 miles, well before Hyundai’s recommended 80,000-mile replacement interval for its fluid. Compounding the situation, kuueon had flagged related noise concerns back at 35,000 miles. “They kept insisting it’s a sealed unit and you can’t [service it], despite Hyundai’s own manual saying to inspect it at 35k,” they wrote. This disconnect between factory recommendations and dealership behavior is a familiar frustration for modern car owners, and not just with Hyundai.

Stereotypes exist for a reason. And while the one about Korean automakers being second-rate is long obsolete, Hyundai’s made a legitimate claim to being a top-tier manufacturer, the stereotype of service departments being bureaucratic black holes hasn’t gone anywhere. From the moment kuueon walked into the dealership, they were met not with solutions, but a shrug. 

Hyundai Ioniq 5 Drivetrain Failure: Warranty & Rental Costs

The reduction gear was covered under warranty, but the out-of-pocket rental car costs, Uber rides, and unclear diagnostics fees added insult to drivetrain injury. “Call corporate,” the service rep allegedly told them. “Nothing we can do.” That’s a brutal answer when you’ve just dropped $550 on unrelated maintenance for a car you can’t even drive.

Other Redditors chimed in with similar stories. “I’d have thought noise around the motor when you accelerate likely was the same complaint,” wrote one commenter, reflecting a common theme: the original issue might’ve been preventable. Kuueon had even let the dealer keep the car over a weekend just before the 60,000-mile mark, when the issue conveniently disappeared, only to return at 61k. A cynic might say the problem resurfaced just in time to flirt with the warranty’s limits. And while kuueon is the original owner, their comment, “I tend to avoid buying used because I like being able to avoid crap like this,” captures the irony better than anything else could.

This isn’t just a Hyundai problem. One look across forums reveals a pattern. An Ioniq 5 sits in the shop for months while owners rent from friends to avoid exorbitant daily rates. Another Tucson owner racks up nearly $2,000 in rental fees, only to learn Hyundai will only reimburse $35 per day, if approved. Even after engine replacements are greenlit, parts delays and radio silence from corporate leave drivers paying out-of-pocket just to get to work. As one forum member noted bitterly, “They decided they will not reimburse me anything because I rented from a third party.”

Hyundai Ioniq 5 Charging Specs: Fast DC & Home AC Timings

• Under optimal conditions on a 350 kW DC fast charger, the Ioniq 5 can charge from 10% to 80% in about 18 minutes 
• Even on a 150 kW charger, it still reaches 80% in under 30 minutes, depending on battery and ambient temperatures 
• takes approximately 6 hours and 40 minutes 
• Standard 7 kW AC charging (typical home setup) fills the battery fully in around 9 hours, adding roughly 26 km of range per hour

The Ioniq 5 is, by most accounts, a triumph. It’s a bold, clean-sheet design with stunning retro-futuristic styling and advanced 800V charging tech. It deserves its praise.

Hyundai has earned its reputation for design and value, but it risks losing that goodwill if its service infrastructure doesn’t evolve to match its product ambitions. Warranty promises are easy to market, and harder to deliver. Every automaker stumbles, but how they handle those stumbles makes the difference. For kuueon, that difference is measured in rental car receipts and unanswered calls. And for the next buyer browsing the Ioniq 5 online, stories like this one may carry more weight than any spec sheet or award.

Image Sources: Hyundai Media Center

Noah Washington is an automotive journalist based in Atlanta, Georgia. He enjoys covering the latest news in the automotive industry and conducting reviews on the latest cars. He has been in the automotive industry since 15 years old and has been featured in prominent automotive news sites. You can reach him on X and LinkedIn for tips and to follow his automotive coverage.