Top speed?

I've had my 6th gen for almost two years and I've already had my tranny replaced. At about 17k miles, a trans-axle seal busted. At about 38k it happened again. The dealer just opted to completely repalce the tranny under warranty. My new tranny feels better, but I've noticed that my top speed is down. Although I never took it to the limit before, I can't seem to get past 110mph with the new tranny. The car just stays at the same rpm and doesn't cut out, just keeps the same speed. I've been at least 115 before, so I know something is up. Is it the new tranny? Can it be something else? How can I regain what I hadd before?