P0732 on Acura: How to Diagnose & Fix
Gear 3 Incorrect Ratio
2 Acura models · 2 documented issues · 2 critical · $2,500-$6,500 repair
P0732 on Acura by model: symptoms, diagnosis and fix
The ZF 9HP 9-speed automatic introduced on the 2016 MDX suffers from documented hesitation, harsh shifts, lurching, and unexpected downshifts/deceleration. Drivers report the vehicle hesitating from a stop, banging into gear, or briefly losing power. Software miscommunication between TCM, ECM and throttle control is the alleged root cause; a class action was filed alleging Honda knew of the defect from 2015.
Common Symptoms
- Hesitation from a stop
- Hard or banging shifts
- Unexpected downshift while cruising
- Brief loss of power
- Lurching at low speed
How to Fix
Have dealer apply latest TCM/PGM-FI software updates first (covered by powertrain warranty). If symptoms persist, request fluid replacement and dealer escalation; document everything for lemon-law/class-action relief. Avoid jerky throttle inputs while cold.
Sources for this issue (3)
1999 was the launch year of the 2nd-gen TL with the 3.2L J32A V6 and a new 5-speed automatic. This transmission family turned into one of the worst Acura defects of the early 2000s — torque converter failure, 3rd-gear clutch pack burn-up, blocked oil passages from debris, and complete failure became common. American Honda extended the transmission and torque converter warranties in 2003 (per TSB 02-027). The 1996-1998 TL uses the older 4-speed automatic which is generally reliable; the failure pattern is specifically the 5AT introduced for 1999. If you are car-shopping a 1999 TL, the model year alone does not tell you which transmission you have — the early-1999 carryover may have the older 4AT while the mid-year 2nd-gen launch got the 5AT. Check the build date and trans serial to know.
Common Symptoms
- Flaring on 2nd-to-3rd or 3rd-to-4th upshifts
- Harsh 'thunk' downshifts when slowing
- Slipping in 3rd gear under load
- Transmission shudder at highway cruise
- Burnt-smell or dark transmission fluid
- Check engine light with P0700-series transmission codes
- Complete loss of forward drive (catastrophic stage)
How to Fix
If you own a 1999 TL with the 5AT and it's slipping, flaring on shifts, or showing harsh 1-2 / 2-3 changes: STOP driving aggressively immediately. The damage compounds quickly. Get a transmission specialist (not a dealer) to drop the pan and check for clutch material in the fluid. If found, the only durable fix is a rebuilt transmission ($2,500-4,000) — not a fluid change, not a solenoid swap. The original Honda warranty extension to 7/100k expired in 2006, so out-of-pocket cost is now on the owner. Many owners install an aftermarket transmission cooler with the rebuild — the original spec is undersized for the load and contributed to the failure pattern. Avoid 'flush' services — pressurized flushes on a worn transmission accelerate failure by dislodging clutch debris.
Owner tips & cautions
- WarningDo NOT 'flush' a worn 5AT. Pressurized flushes dislodge clutch debris from the case and accelerate the death of a struggling transmission. Drop and fill with manual fluid changes only.
- TipAlways add an aftermarket transmission cooler with any rebuild. The factory cooler is undersized for this transmission's load and was a contributing factor to the original failure pattern.
- TipWhen shopping a 1999 TL used, check the build date and transmission serial number. Cars built before the mid-year 2nd-gen launch have the older 4-speed and are far more reliable.
Sources for this issue (2)
P0732 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0732 mean on a Acura?
P0732 stands for "Gear 3 Incorrect Ratio." This code means the transmission control module detected that the gear ratio in 3rd gear does not match what it expects when the transmission is commanded into that gear. The computer compares input (turbine) speed to output shaft speed; if the math for 3rd gear is wrong, it sets this code. It usually points to internal slipping or a hydraulic/electronic control fault rather than a sensor reading error. On Acura it is documented across 2 models: MDX, TL.
What are the most common causes of P0732?
The most common causes of P0732 are: Low or dirty/degraded transmission fluid, Worn clutch packs or friction material in 3rd gear circuit, Faulty shift solenoid for 3rd gear, Valve body or pressure control problems, Internal mechanical wear or damage in the transmission, Clogged transmission filter restricting flow, Faulty input/output speed sensor giving skewed data. The specific cause varies by vehicle.
How much does it cost to fix P0732 on a Acura?
Published repair estimates on Acura range from $2,500 to $6,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0732 on a different make?
View P0732 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.