2000 4 Runner not shifting into drive

I have an automatic & sometimes when I push the gas pedal - nothing happens - then it will "jerk" into gear. My hubby thinks that flushing the transmission will fix this, I have been told by 2 separate garages that it will most likely make it worse. Has anyone else had any experience with this problem. ( I have around 127,000 miles on it.

I vote for your husband's opinion. Flush the transmission. The only way flushing will hurt is if your transmission is ready to fall apart and the only thing giving your clutches traction is brown sticky sludge instead of transmission fluid.