Toyota Motor Corp. (NYSE: TM) has moved into Ford Motor Co. (NYSE: F) sandbox and has started smashing Ford's mighty sandcastles. That's right -- Toyota trucks, notably the Tundra full-size pickup, are taking market share left and right in the state of all truck states, Texas.

Domestically, one in seven large trucks is sold in the state of Texas, and while truck sales from General Motors Corp. (NYSE: GM), Ford and Cerberus-owned Chrysler have declined 5% recently, Toyota's large truck sales have increased 79%. This is due in no small part to Toyota's aggressive incentive spending that really makes the Tundra look like a much-less-expensive but just as powerful option to competitor trucks.

GM has said in the past that it won't match Toyota's incentive spending but will rely on superior products instead. However, with customers tightening their wallets and consumer credit harder to come by, pricing does matter and Toyota is shipping up on the domestic truck makers. Sam Pack, who owns three Ford dealerships in Dallas, Texas, said that Tundra sales "are coming from traditionally Ford, Chevrolet and Dodge ... have they negatively affected Ford? No question they have.'' Ouch. Toyota also recently committed to a $1.28 billion manufacturing plant in San Antonio to make the Tundra. Does Toyota want to seize the full-size truck market? 100%. Absolutely. It now has the manufacturing location and incentive planning to do just that.

General Motors Corp. (NYSE: GM) has announced plans to cut back vehicle production at six plants inside its N.American operations. GM plant scale backs are not really news anymore (as they happen all the time), but this recent announcement has to do with GM's perennial best-sellers: large pickup trucks and SUVs. We all know that SUV sales have plummeted in the last 24 months as gas prices have made American consumers opt for more gas-efficient vehicles, but large trucks are one of the most profitable and popular GM products.

So, what is going on with GM's truck sales? Possibly nothing, as the automaker says that it just wants to decrease the amount of inventory on dealer lots. This reduction in truck and SUV building at six U.S. plants will speed that goal along. Once national dealer inventory returns to 'normal' (whatever that may be), will GM resume full production of large-model trucks under its various brands?

Hard to say, but when questions pop up every single month about how Toyota Motor Corp. (NYSE: TM) Tundra is taking market share away from GM's larger trucks, one has to wonder. The Tundra does not have the track record of GM's reliable truck lines, but overly aggressive customer incentives and consumer marketing are causing more truck customers to take notice. This steals attention away from GM's truck products as well as Ford's F150 truck series, currently the best-selling truck line in the U.S. Is GM's "no-interest" loan strategy along with large customer rebates going to help move more trucks off lots during the remainder of 2007? It may help, but more action is apparently needed. Hence, we have production cutbacks on some of GM's best overall vehicle sellers.