Why does my 2013 Infiniti JX35 shudder when I accelerate gently?

Short answer: On the 2013 JX35, a shudder, buck or vibration when you accelerate gently between about 5 and 45 mph is a well-known CVT (continuously variable transmission) problem that Infiniti calls 'judder'. Infiniti bulletins tell dealers to update the transmission computer first, then inspect and replace the valve body or the whole CVT if judder codes are stored. Owners got it fixed this way, often under warranty or extended warranty.

Symptom: A shake or shudder like rumble strips, or a bucking feeling, during light acceleration at low speed. It often stops if you press the gas harder.

What to check first

1. Note exactly when it happens: speed, how hard you press the gas, warm or cold. Infiniti's first bulletin describes 5–35 mph at very light throttle.
2. Ask the dealer to check for codes P17F0 or P17F1. These are Infiniti's judder codes, and a later bulletin uses them to decide the repair.
3. Ask for the transmission computer (TCM) update if it hasn't been done.
4. Check the CVT fluid condition and service history.
5. Check any extended warranty paperwork. Owners pushed for repairs under extended coverage.

Likely causes

1. Transmission computer (TCM) software. The first step in Infiniti's bulletin.
2. Worn or faulty CVT valve body (control valve). Replaced when judder code P17F1 is stored and the chain checks out.
3. Internal CVT wear (chain or pulleys). Code P17F0 usually means the CVT is replaced.

What it usually costs

We don't have reliable out-of-warranty prices from owners. Owners in these threads had repairs done by Infiniti under warranty or extended warranty. A CVT replacement is a major cost if you pay yourself, so check coverage first.

Is it safe to keep driving?

Usually drivable, but a judder that gets worse can turn into a failing transmission. Get it checked soon, and stop driving if it slips, flares or warning lights come on. Verify with a mechanic.

DIY or shop?

Dealer. Software, code checks and valve body or CVT replacement need Infiniti tools.

Recalls, bulletins and complaints in plain words

• Bulletin AT13-018 (2013 JX, 2014 QX60): judder during light acceleration at 5–35 mph. Dealers reprogram the transmission computer and then diagnose further if needed. A bulletin is repair guidance for dealers, not a free-repair promise.
• Bulletin AT15-007 (2013 JX35, 2014–2018 QX60 V6): for judder with codes P17F0 or P17F1. Dealers inspect the CVT chain and replace the valve body or the CVT.
• Other recalls on the 2013 JX35: NHTSA lists recalls including 13V445 (ABS software that can lengthen stopping on rough roads), 13V139 (front brake torque member casting) and 12V398 (fuel gauge reading high). None is for the CVT judder. If your car is part of a recall, the dealer fixes it for free.
• NHTSA complaints: 91 keyword-matched complaints for Infiniti JX35 2013 (of 296 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-21; keywords: CVT, transmission, judder, shudder, jerk, hesitation, cooler line, surge, loss of power) (NHTSA returned no complaint data for 1 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In JX35 CVT transmission problems on the Infiniti QX60 Forum, an owner with an extended warranty said the JX shuddered badly around 40 mph and bucked at 35–45 mph. Members said it was very common on JXs, mostly fixed by reprogramming and sometimes by replacing the CVT. The owner later said Infiniti replaced the transmission control valve assembly and it drove better than when they bought it.
• In U.S. safety regulators opened an investigation on the same forum, owners discussed a 2013 federal investigation into JX35 and Pathfinder transmission cooler line connections, and members described the judder as the engine briefly disconnecting and reconnecting as the CVT changed ratio.

Quick tip

For a JX35 or early QX60, ask for the dealer service history and look for the CVT bulletin work. A smooth test drive at light throttle from 10 to 45 mph tells you a lot.

Vehicle focus: 2013 Infiniti JX35 (same vehicle as the early QX60).

Safety / mechanic note

A failing transmission can lose power in traffic. Verify with a mechanic.