Is there any advice on how fast you can go and still shift into 3rd with the button on the shifter of an AT 240? I drove through the mountains of western MD and WV and had to downshift to maintain speed on the steeper climbs, only to lose speed and hold about 60, sometimes 65. I also blew out the rear muffler, making for a noisy return trip.

I just want to know if there is a speed above which you shouldn't downshift into 3rd.

Thanks for all replies.