Service bulletin T-TT-0394-16

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
Type	Service bulletin
NHTSA id	10140575
Published by NHTSA	2018-06-11
Manufacturer's number	T-TT-0394-16
Manufacturer's date	2016-05-05
NHTSA component	POWER TRAIN:TRANSFER CASE (4-WHEEL DRIVE)

NHTSA's summary

TT: Some customers may experience a stuck in 4HI or 4LO condition due to a damaged transfer case actuator. After replacing the actuator, the normal operating condition is restored. Investigation of recovered parts show that damage is due to improper shifting pattern from N to D during 4LO entering/exiting operation.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Transmission and driveline, Transfer case

Vehicles listed
TOYOTA TACOMA	2016

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
T-SB-0011-18	2018-03-12. Service bulletin. TSB: Some 2016 ? 2018 model year Tacoma 4WD vehicles may exhibit a cyclical groaning or grinding noise coming from the front differential in 2WD that is not present during 4WD operation. Follow the Repair Procedure in this bulletin to address this condition. APPLICABLE WARRANTY ? This repair is covered under the Toyota Powertrain Warranty. This warranty is in effect for 60 months or 60,000 miles, whichever occurs first, from the vehicle?s in-service date. ? Warranty application is limited to occurrence of the specified condition described in this bulletin.
T-TT-0394-16	2017-02-23. Service bulletin. TT: SOME CUSTOMERS MAY EXPERIENCE A STUCK IN 4HI OR 4LO CONDITION DUE TO A DAMAGED TRANSFER CASE ACTUATOR. AFTER REPLACING THE ACTUATOR, THE NORMAL OPERATING CONDITION IS RESTORED. INVESTIGATION OF RECOVERED PARTS SHOW THAT DAMAGE IS DUE TO IMPROPER SHIFTING PATTERN FROM N TO D DURING 4LO ENTERING/EXITING OPERATION.