2003 Toyota Tundra, (4WD) VIN 5tbbt44143S36074 there is a very obvious vibration and humming noise coming from the front transfer case / differential. This causes a slight reduction ins speed and / or resistance to acceleration. The problem is most noticeable between 30 ~ 40 mph in colder weather, but is present at all speeds and weather conditions. The problem has been present since purchasing the vehicle as new, and is becoming progressively worse. Toyota recognizes and acknowledges that there is a defect with some of the 2003 thunders and squish (documented in service report for this vehicle). It was describe to me by two Toyota service managers and a Toyota technical assistance representative as resulting from the fit / mesh tolerance of some gears in the front gear case being too tight. Toyota has fixed the problem (re-design) in current production vehicles (starting some time during the 2003 model year production schedule), but has to date refused to repair the defect for all owners presenting this problem to authorized Toyota dealers / service centers. Some dealers / service centers have repaired the defects at random. I suspect and fear that this problem will eventually lead to a failure of some kind that may present a safety hazard, I.e. gears wearing, slipping, or binding) when the vehicle is in motion, and this in turn may cause a loss or reduction of, or interference with, driver control.

- Lexington, KY, USA

While driving there was a noise heard coming from under the hood. Dealer has inspected the vehicle and could not duplicate or correct the problem. Ts the defect was with the transfer case which caused vibration and reduction in speed.

- Pen Argyl, PA, USA