Sales of body-on-frame SUVs have been on the decline over the last several months, but that won't stop Lexus from launching a new version of its GX mid-size SUV. The current GX has been on the market since 2003 but will be replaced by an all-new model during the second half of the year.

According to Ward's, a new version of the Lexus GX SUV will debut this fall. The new model will include all-new sheet metal as well as a revised interior. However, the mid-size "?ute will retain its body-on-frame construction.

"The largest SUVs have been hit the hardest, but there's still a segment of the population that wants those vehicles," Lexus General Manager Mark Templin told Ward's.

The new GX will also receive a significant overhaul underhood. Whereas the current rig uses a 4.7L V8 rated at 263 horsepower, the new model will borrow the 310 horsepower 4.6L V8 from the 2010 Toyota Tundra.

Sales of the GX have been on the decline since 2004. In that year Lexus sold 35,420 units of the GX - exceeding Toyot's expectations of 20,000 annual sales - but sales have been on the decline ever since. Last month GX sales were down more than 66 percent, but Lexus is hopeful a new look GX will be just the ticket to bolster demand.