Why does my 2017 Genesis G80 shift hard once it warms up?

Short answer: Many 2017 G80s develop hard, clunky upshifts, usually between 2nd and 5th gear and only after the car is warm. Genesis has a service bulletin for it that replaces two shift solenoids (small valves inside the transmission that control each gear change). Owners say that fixed it.

Symptom: A hard bang or jolt on the 2–3, 3–4 or 4–5 upshift, often after 20–30 minutes of driving, sometimes strong enough to feel like being hit from behind.

What to check first

1. Check the 10th digit of your VIN. The bulletin applies to 2017 G80s with an 'H' there (3.8L or 5.0L).
2. Note when it happens. Owners say it shows up only after the transmission is warm, which is why short test drives miss it.
3. Ask a Genesis dealer for bulletin 21-AT-010HG by number.
4. Ask whether your powertrain warranty still covers it. Out of warranty, owners say it's a paid repair.

Likely causes

1. Faulty 35R and 4&OD shift solenoids. Genesis bulletin 21-AT-010HG replaces these two solenoids with updated parts.
2. Internal transmission damage (if harsh shifts continue after the solenoids). The bulletin tells the dealer to get approval for a transmission replacement if the problem continues.

What it usually costs

I couldn't find a reliable out-of-warranty price for the solenoid job. Owners on Genesis Owners say the dealer did it under warranty. If you're out of warranty, get a quote that names the bulletin, since it lists the exact parts.

Is it safe to keep driving?

Usually yes for short trips, but don't ignore it. Repeated hard shifts wear the transmission and driveline, and a sudden slam at the wrong moment can startle you in traffic. Get it to a dealer soon. Verify with a mechanic.

DIY or shop?

Dealer or transmission shop. The solenoids are inside the transmission and need a scan tool to reset afterward.

Recalls, bulletins and complaints in plain words

• No recall covers the harsh shifting.
• Genesis bulletin 21-AT-010HG: for 2017 G80 3.8L and 5.0L with harsh 2–3, 3–4 or 4–5 upshifts. Dealers replace the 35R and 4&OD solenoids with revised parts, then check again; if it continues, they ask Genesis for approval to replace the transmission.
• Recall 24V107 (2017–2019 G80): a different solenoid, on the starter, can let in water and short, possibly causing a fire. If your car is part of this recall, the dealer fixes it for free. Don't mix the two up.
• NHTSA complaints: 7 keyword-matched complaints for Genesis G80 2017 (of 66 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-17; keywords: transmission, shift, solenoid, jerk, harsh, slam).

What owners report

• A Genesis Owners thread shared the bulletin, and owners reported the dealer replaced both solenoids under warranty and the hard shifts stopped.
• In r/GenesisMotors, an owner warned a shopper that a portion of 2017 G80s have this transmission issue, that the bulletin replaces solenoids, and that it isn't covered once you're out of warranty.
• In a thread on common Genesis issues, owners listed 2017 G80 transmission solenoid problems and harsh shifts in Sport mode.

My take

My advice as a former car salesman: test drive a used 2017 G80 for at least half an hour so the transmission gets fully warm. Then ask for the dealer service history and look for 21-AT-010HG. If it's been done, that's a plus.

Vehicle focus: 2017 Genesis G80 with the 3.8L V6 or 5.0L V8 (VIN 10th digit 'H').

Safety / mechanic note

A sudden harsh shift can startle you in traffic and wears the drivetrain. Verify with a mechanic.