Ok,

I will be the first one to admit i know nothing about automatic transmissions, i know manuals and sequentials. so excuse my what may be simplistic question.

I have a 2006 scab fx4. i have 7k miles on it. Ive always felt like the trans slips a lot, i took it to the dealer, they said something was definatley wrong with it, and then called me back the next day and said everything was fine. This week my father bought the same truck, hes is no where as bad as mine. Then today i notice, i back up my drive way, probably a 20 degree slope from horizantal, and i take my foot of the brake, and my truck rolls down the drive way, still in reverse mind you. So i pull out, pull into the drive, check it, and the truck rolls backwards down the drive way.

I pull my dads truck out, try his, it stops, doesnt roll at all.

So my question is, should an auto trans roll down a hill in gear, if the gear is in an apposite direction that it rolls?

Please help, im tired of getting 8 mpg and having no acceleration.

 

Thats likely has more to do with the stall of the converter than the transmission. a higher stall converter as found in some 5.4's and all 4.6 engines will likely roll back. Certain 5.4's and diesel trucks have a lower stlal converter it takes a really good grade to make them roll back.
Alan