TSB: REVISION NOTICE July 01, 2019 Rev2: ? Applicability has been updated to 2019 ? 2020 model year Toyota vehicles. ? The Techstream Preparation and Process Overview sections have been updated. October 30, 2017 Rev1: ? Applicability has been updated to include 2018 model year vehicles. Any previous printed versions of this bulletin should be discarded. SUPERSESSION NOTICE The information contained in this bulletin supersedes SB No. T-SB-0012-13. Service Bulletin No. T-SB-0012-13 is obsolete and any printed versions should be discarded. Be sure to review the entire content of this bulletin before proceeding. Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated
full bulletin at NHTSA ↗2008 Toyota Avalon powertrain problems
severe 11 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Complaints
11
Recalls
0
Avg fix
$2,500
3crashes
1injury
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
TSB: This bulletin includes basic procedures for inspecting and adjusting World Standard (WS) Automatic Transmission Fluid (ATF) level at normal vehicle operating temperature. Note: The following adjustment procedures are for U660E/F and U760E/F transmissions.
full bulletin at NHTSA ↗TechTip: Condition - The vehicle may be difficult to start or have an abnormally low or rough idle after the battery has been disconnected or power to the Engine ECM has been interrupted.
full bulletin at NHTSA ↗TSB: World Standard (WS) Automatic Transmission Fluid (ATF) was introduced to reduce maintenance costs and increase the mileage between scheduled maintenance checks. Here are some important tips when working with ATF-WS in Toyota vehicles requiring it's use.
full bulletin at NHTSA ↗TSB: The purpose of this bulletin is to provide precautions to follow when installing an automatic transmission/transaxle assembly to avoid MIL "ON" shifting issues and/or transmission damage. Use the information in this bulletin when installing an automatic transmission/transaxle assembly.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of the 2008 Avalon report multiple powertrain and safety failures. The most serious allegation involves a sticky accelerator pedal that sticks in full throttle, causing uncontrolled acceleration. Three separate incidents describe sudden violent engine revving and acceleration—one at carwash exit, one in a parking lot, and one while stopped in traffic. One owner was trapped in a runaway vehicle that hit a pole, went over an embankment, and crashed into opposite-direction traffic, resulting in $12,226 in damage.
Transmission problems also appear frequently: one owner had complete transmission failure at 48,000 miles; another experienced transmission overheating that caused deceleration. A third owner discovered a leaking transmission pan seal that allowed fluid loss; when he added one quart, fluid still poured out. He experienced shuddering at cruising speeds with no warning lights.
Owners report a design flaw where the push-button start/stop switch can shut off the engine even when the transmission is in gear, allowing the car to roll freely. One owner accidentally did this in a garage. The shift lever itself sticks when trying to move from park to reverse.
A dealer dismissively told one owner that violent RPM increases were "normal." Another owner's airbags failed to deploy during a collision caused by sudden acceleration. One case involved an unexplained loud rattling noise under the hood with check engine and VSC lights illuminated, which cleared on restart but the dealer couldn't identify the cause.
Same Toyota Avalon powertrain reports on nearby years: 2005 · 2006 · 2007
Failure modes owners describe
Accelerator Pedal Sticks / Unintended Acceleration
Accelerator pedal sticks in full throttle position, causing sudden uncontrolled acceleration with loss of vehicle control. Occurs when shifting from neutral to drive or during normal driving. Owners report engine revving violently and vehicle accelerating at low speeds without driver input.
When: At various mileages; reported during carwash exit, low-speed parking lot entry, and while stopped in traffic
Symptoms owners cite: Accelerator stuck in full throttle; Sudden uncontrolled acceleration; Loss of vehicle control; Engine revving violently; Acceleration when foot on brake; No warning lights prior to failure
Repairs/costs cited: Owners report extensive collision damage requiring replacement of battery, oil pan, rear engine cradle cushion, pipes, bumpers, grille, hood, mirrors, exhaust system, tires, and rims. One owner cited $12,226.39 in total damages.
Recalls/TSBs owners mention: Toyota issued recall for accelerator pedal sticking. Dealer stated rapid RPM increases were 'normal characteristic of the vehicle' in one case.
Transmission Failure / Loss of Drive
Transmission loses ability to move vehicle forward or backward; wheels stop spinning entirely. Owners report transmission must be replaced at relatively low mileage. One owner claims dealer blamed 'outside influences' for failure despite comprehensive warranty coverage.
When: At 48,000 miles; one case of transmission overheating in April 2018
Symptoms owners cite: Vehicle will not move forward or backward; Wheels stop spinning; Transmission must be replaced; Transmission overheating and causing deceleration
Repairs/costs cited: Owner had to tow vehicle to dealership. New transmission required at owner's expense; dealer claimed comprehensive warranty does not cover 'outside influences.' Another owner added quart of transmission fluid when pan seal leaked.
Recalls/TSBs owners mention: Dealer refused warranty coverage, citing 'outside influences' as cause of failure.
Transmission Fluid Leak / Low Fluid
Transmission pan seal leaks transmission fluid, creating wet pan underneath vehicle. Owner discovers leak after experiencing shuddering during driving. Unable to check transmission fluid level due to design of fluid check procedure.
Symptoms owners cite: Transmission pan wet underneath; Vehicle shudders at 30 mph and 45 mph during cruise; No warning lights on dashboard; Shuddering during curves
Repairs/costs cited: Owner added one quart of transmission fluid before it showed proper level on check. Suspected torque converter or transmission damage from low fluid condition.
Engine Rattle / Loud Noise Under Hood
Extreme loud rattling noise from under hood during engine start, described as sounding like an old cowbell being shaken. Check engine light and VSC light illuminated. Noise and warning lights disappear on restart and dealer cannot replicate issue or find cause.
When: January 17, 2010
Symptoms owners cite: Extreme loud rattle from under hood; Check engine light on; VSC light on; Noise disappears on restart; Warning lights clear after restart
Repairs/costs cited: Dealer checked vehicle, test drove it, found nothing wrong. Stated issue 'reset itself.'
Engine Start/Stop Switch Allows Shutdown in Non-Park Gear
Engine can be shut off with automatic transmission not in park position, allowing vehicle to roll freely. Push-button start/stop switch design does not prevent engine shutdown when shifter is not in park. No interlock switch prevents this safety hazard. Poor steering and braking response when engine is running and transmission not in park.
Symptoms owners cite: Engine shuts off with transmission in gear; Vehicle rolls freely after engine shut off; Poor steering response when engine off; Poor braking response when engine off
Shift Lever Stuck in Park / Difficult Gear Selection
Shift lever difficult to move from park position to reverse or other gears. Lever 'wiggles' but resists movement from park. Problem occurs intermittently and repeatably within short timeframes.
When: June 2010
Symptoms owners cite: Shift lever won't move from park to reverse; Shifter wiggles but resists movement; Requires multiple attempts to engage reverse; Intermittent sticking in park position
Repairs/costs cited: Owner planned to take vehicle to dealership for repair.
Airbag Non-Deployment in Collision
Airbags fail to deploy during head-on collision with pickup truck at low speed after sudden acceleration event. Vehicle sustained $5,600 in damage to front bumper area, but airbags did not activate.
When: During sudden acceleration accident while stopped in traffic
Symptoms owners cite: Airbags did not deploy in collision; Head-on impact with truck; Vehicle front bumper went under truck rear bumper
Repairs/costs cited: Vehicle sustained $5,600 front-end damage.
Synthesized from 11 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had powertrain trouble with your 2008 Toyota Avalon?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2008 Toyota Avalon?
It's a meaningful issue. 11 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $2,500.
At what mileage does the powertrain typically fail?
Based on the 11 complaints filed, powertrain issues most often appear around 29,879 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2008/Toyota/Avalon.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.