P0733 on Acura: How to Diagnose & Fix
Gear 4 Incorrect Ratio
1 Acura model · 1 documented issue · 1 critical · $2,500-$4,500 repair
P0733 on Acura by model: symptoms, diagnosis and fix
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)
P0733 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 P0733 mean on a Acura?
P0733 stands for "Gear 4 Incorrect Ratio." This code indicates the transmission control module found that the actual gear ratio in 4th gear is outside the acceptable range for that gear. It is detected by comparing transmission input speed against output speed while 4th gear is engaged. A mismatch typically signals the transmission is slipping in 4th gear or that a control/hydraulic fault is preventing proper engagement. On Acura it is documented across 1 model: TL.
What are the most common causes of P0733?
The most common causes of P0733 are: Low or contaminated transmission fluid, Worn 4th-gear clutch packs or bands, Failing shift solenoid for 4th gear, Valve body or line pressure issues, Internal transmission mechanical wear, Restricted transmission filter, Faulty input or output speed sensor. The specific cause varies by vehicle.
How much does it cost to fix P0733 on a Acura?
Published repair estimates on Acura range from $2,500 to $4,500 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 P0733 on a different make?
View P0733 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.