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 Service Bulletin No. T-SB-0012-13 is obsolete and any printed versions should be discarded.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 ↗2006 Toyota 4Runner powertrain problems
severe 20 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
20
Recalls
0
Avg fix
$2,500
3crashes
3injuries
What stands out
Among the 11 model years of Toyota 4Runner in our records for powertrain problems, this one ranks #2 by owner-complaint volume.
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: REVISION NOTICE June 8, 2018 Rev2: ? Applicability has been updated to exclude 2016 ? 2017 model year Tacoma vehicles. ? The Repair Procedure section has been updated. May 15, 2017 Rev1: ? Applicability has been updated to include 2016 ? 2017 model year Tacoma and 4Runner vehicles. ? The Introduction section has been updated. Any previous printed versions of this bulletin should be discarded. Some 2004 ? 2017 model year 4Runner vehicles, 2007 ? 2014 model year FJ Cruiser vehicles, and 2005 ? 2015 model year Tacoma vehicles equipped with part-time 4WD may exhibit a cyclical groaning or grinding noise coming from the front differential in 2WD that goes away when operated in 4WD. This nois
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: Some 2004 - 2015 model year Tacoma, FJ Cruiser, and 4Runner vehicles may exhibit a cyclical grinding or groaning noise coming from the front differential in 2WD that goes away when operated in 4WD. This noise can be addressed by replacing the needle bearing on the left side of the front differential. Refer to the Repair Procedure for Needle Bearing Roller replacement instructions.
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 ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of the 2006 Toyota 4Runner report a cluster of powertrain failures, with the driveline clunk standing out as the most common complaint. Starting around 25,000–53,000 miles, vehicles develop a sharp clunking or banging noise when stopping at lights or accelerating away, with some owners experiencing the clunk on nearly every stop-and-start cycle. Several describe the sensation as being rear-ended, and a few report the vehicle lurching forward during braking—a potential safety concern in traffic.
Dealers identified a worn yoke and wear in the driveline as the culprit but offered inconsistent fixes. Lubrication of the driveline zerk fitting provided only temporary relief lasting weeks before the noise returned and often worsened. One owner reported a V8 was fixed by installing a Lexus driveline, but V6 owners were told no equivalent replacement existed.
Beyond the driveline, owners report rear differential seal leaks starting as early as 10,000 miles, oil leaks from crankshaft seals that saturated engine bays and destroyed drivetrain components, and a failure of the 4WD ADD (Auto Disconnecting Differential) actuator that left a vehicle unable to engage 4WD during winter snow—a critical safety loss. Two owners alleged sudden unintended acceleration at highway speeds, though one Toyota data download concluded the pedal was normal, and another owner later attributed the issue to pedal spacing and footwear, not a vehicle defect. Vibration complaints at highway speeds were dismissed by dealers as normal for the model.
Same Toyota 4Runner powertrain reports on nearby years: 2005 · 2007 · 2008
Failure modes owners describe
Driveline clunk on stop/start
Owners report a distinct clunking or banging noise from the driveline when coming to a stop or accelerating from a stop. The sound is often forceful enough that drivers think they've been rear-ended. Multiple owners report this began early in vehicle ownership (25k-53k miles) and persists or worsens despite dealer lubrication attempts.
When: 25,000–53,000 miles; occurs at traffic lights and stop signs during braking and acceleration
Symptoms owners cite: Clunking noise from driveline when stopping; Vehicle lurches or moves forward unexpectedly during stops; Sound resembles rear-end impact; Occurs repeatedly; some owners report every stop, others intermittently
Repairs/costs cited: Dealers applied driveline lubrication at zerk fitting; temporary relief lasting weeks to months before noise returns and worsens. One owner reported V8 fixed by driveline/yoke replacement with Lexus unit; V6 swap not available. Another owner had entire drivetrain rebuilt due to oil damage from separate crankshaft leak.
Recalls/TSBs owners mention: Service Bulletins referenced: SB 00207, SB 00106 (one owner cited). Lexus GX470 has TSB for same issue. Toyota dealer acknowledged awareness of problem but initially claimed no fix available; lubrication offered as temporary measure. No recall or warranty extension announced by owners.
Driveline vibration at highway speeds
Owner reports cyclical droning vibration felt throughout the cabin and steering at highway speeds (72–74 mph), worsening under load or hard acceleration. Vibration accompanied by clunk on stop/start. Dealer and district service manager dismissed as normal for vehicle type.
When: 4,575 miles; ongoing at highway speeds
Symptoms owners cite: Cyclical droning vibration at 72–74 mph; Vibration felt on driver floorboard, dead pedal, accelerator pedal, and steering wheel; Worse when climbing grades or under engine load; Noticeable during full-throttle acceleration from stop; Clunk when coming to a stop and starting from complete stop
Repairs/costs cited: Dealer inspection found no defect; deemed normal. No repair attempted.
Recalls/TSBs owners mention: Dealer and district Toyota service manager declined to address, stating it is normal for the vehicle type.
Driveline yoke wear and looseness
Dealer identified worn yoke on driveline as root cause of clunking and lurching. Issue acknowledged by multiple dealerships as a known defect affecting both V6 and V8 models, but remedies were inconsistent and often inadequate.
When: 40,000+ miles
Symptoms owners cite: Clunking sound from driveline; Vehicle lurches forward while braking at stop; Problem escalates from occasional to frequent
Repairs/costs cited: Initial fix: driveline lubrication at zerk fitting (temporary, lasting weeks). V8 resolved by Lexus driveline replacement; V6 had no equivalent replacement option per owner report.
Recalls/TSBs owners mention: Toyota dealers acknowledged being aware of driveline and yoke issues on these vehicles but offered inconsistent solutions.
Rear differential oil leak
Multiple owners report oil leaks from rear differential seal or differential itself. One owner at 10k miles notified of manufacturing defect in seal requiring replacement. Another owner at high mileage (168.5k) found frame rotted due to leak and differential unrepairable.
When: 10,000 miles and 168,595 miles
Symptoms owners cite: Oil pooling in driveway; Visible oil leakage from rear differential area
Repairs/costs cited: Seal replacement ordered (10k miles case). At 168.5k miles, frame corrosion was so severe repair deemed impossible by dealership.
Recalls/TSBs owners mention: Acknowledged as manufacturing defect by dealer at 10k miles; part on backorder. No information on recall or extended coverage.
Secondary Air Induction (AIP) pump and switching valve failure
Owner reports AIP pump and switching valve failure, the same defect occurring on Sequoia and Tundra models. Toyota extended warranty covers those vehicles but not 4Runner, despite identical defective parts.
When: Not specified; requires over $2,000 to repair
Symptoms owners cite: Check engine light; Unable to pass state emissions inspection
Codes mentioned: Check engine code (specific code not provided)
Repairs/costs cited: Over $2,000 repair cost to clear check engine code and restore inspection compliance.
Recalls/TSBs owners mention: Toyota issued special extended warranty for AIP system on Sequoia and Tundra but not 4Runner, despite identical parts. NHTSA case #1409160408.
4WD ADD (Auto Disconnecting Differential) actuator failure
During winter 4WD engagement attempt, ADD actuator failed, preventing 4WD system from engaging. No warning before failure; only blinking 4WD indicator on dash. Owner slid across overhead bridge in snowstorm, creating dangerous condition. Owner reports part was out of stock due to high failure rate.
When: During winter driving in snow; timing not specified
Symptoms owners cite: 4WD will not engage when commanded; Blinking 4WD indicator light on dashboard; Vehicle slides on snow and ice without traction control
Repairs/costs cited: Part replacement required; owner notes part was out of stock in USA due to high failure rate.
Recalls/TSBs owners mention: No recall mentioned by owner; owner demands Toyota replace part free on all 4WD 4Runners.
Sudden acceleration (alleged)
Two separate allegations of sudden unintended acceleration at highway speeds. In one case, vehicle hit pickup truck despite hard brake pedal application. Toyota's black-box data download concluded gas pedal normal. Second case was traced by owner to unrelated pedal spacing issue and flip-flops; owner notes similar issues not found on other Toyota models tested.
When: Highway driving (60+ mph)
Symptoms owners cite: Vehicle accelerates beyond driver input; Brakes unable to overcome acceleration; RPM increases despite brake application
Repairs/costs cited: One collision occurred; Toyota data showed gas pedal normal. Second case attributed by owner to accidental bridging of pedals with flip-flops, not vehicle defect.
Recalls/TSBs owners mention: Toyota downloaded black-box data and concluded gas pedal normal; no defect found.
Crankshaft seal oil leak
Owner discovered oil everywhere under hood, saturating belts and causing deterioration. Dealership confirmed known oil leak defect near crankshaft. Leak was severe enough to damage entire drivetrain, requiring full rebuild.
When: Not specified; discovered when belts hanging under car
Symptoms owners cite: Oil pooling under hood; Belts soaked and deteriorated; Visible oil everywhere in engine bay
Repairs/costs cited: Entire drivetrain rebuilt due to oil damage; covered under warranty.
Recalls/TSBs owners mention: Dealership acknowledged as known oil leak defect near crankshaft.
Synthesized from 20 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 2006 Toyota 4Runner?
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 2006 Toyota 4Runner?
It's a meaningful issue. 20 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?
Across the 18 complaints that reported odometer mileage, most powertrain failures cluster between 11,500 and 97,000 miles, with the median around 40,000. A quarter of owners report trouble before 11,500; a quarter make it past 97,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
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/2006/Toyota/4Runner.
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.