My 02 tundra has 54000 miles on it. The service manual suggest transmission servicing at several mileage points that I have not done. Why does Toyota require this and GM, along with many other makers, requires no service for 100,000 miles. Is the trans. service that important? Are the transmissions bad enough to warrant that type of service or is it a dealer gimmick to make money?

If it's an automatic transmission, you should have the tranny fluid not only changed every 2 years, you should have it "flushed" every 2 years. The torque converter contains metal shavings (from wear) that will not come out with a regular simple fluid change. Flushing gets everything. It's not expensive, in Canada it's about $100. In real money (yours) it's probably $80. Well worth the investment.

Your tranny will last 100 000 miles no probs. But if you want 300 000, do the maint as I suggest.

Now, if you have a manual tranny, please advise and disregard above flush.

See, and I think that most all the lights and warnings are the dealer's way of making a buck. We have a 1994 4 runner with 470,000 miles and I'm pretty sure we never flushed the transmission.

Id only really change it every two months.