i have a 99 f250 with 6 pos chip and straight pipe. i pull a loaded trailer with it. seems when it shifts from 2nd to 3rd or 3rd to od when pulling hills it shifts really hard . maybe someone could give me some ideas on what would cause this.

 

Any gauges? What are your tranny temps? How many miles on the truck?

 

no gauges yet . it has 152000 on it it only seems to shift when pulling a big hill .

 

I would bet a worn out tranny, Get some gauges and watch the temps.

Start saving your pennys for a new tranny.

 

Who burned the chip for you? What tune are you pulling in? Was it doing that before the chip? Not saying it's the chip, but that might be contributing...

 

its a beans chip i leave it on daily all the time. it had the chip when i got the truck it does great shifting except when pulling a big hill with my trailer. an its only on a specific hill i notice it doing it on.

 

If it only happens on one hill, I wouldn't worry too much about it...

 

ok thanks