dealer reprogramming auto trans?

[cantspell]

Hi there, i work for a company which does lost of business with Ford. Last year, i moved up to 31's, and started to complain about poor gas milage, however i then realized that it was due to the tires, intake and exhust...but one of the thigns they did was reprogram my tranny with the right tire size...WHAT IS THIS? I"ve never heard of the tranny needing reprograming...? I
'm getting 33's now, and i want to know if it's worth bugging them to do it again? (I currently am very happy with the performance of my truck/tranny)

 

[RiverRat]

What the dealer does is change the VSS (vehicle speed )data so the computer will get accurate data again with the larger tires. That way your speedo and shift scheduleing will be correct.

 

[cantspell]

is this very important? I guess this would explain for example why, when it's floored at say 40kph, it down shifts right away, but when i do it at 50kph, it takes for ever? (it's trying to conserve gas?)

 

[Billy177]

33's with 3.55 gears i don't know how well that will work out for you but yes i would get it reprogramed

 

[cantspell]

yeah, i know, well it's really as big as i'll go (well, so we all say right?). But i'm honestly quite happy with the way my X is currently performing, maybe that intake and exhaust are making a little difference.

I've decided to keep the X for some time, i figure it's a decent size to lug things, not too big for the trails and not a total pig on gas (well, that may change with the new tires). So if it's really bad, i'll have to get the gearing changed to 4.10's or 4.56's...It all takes time.

 

[Robert]

Originally posted by RiverRat
What the dealer does is change the VSS (vehicle speed )data so the computer will get accurate data again with the larger tires. That way your speedo and shift scheduleing will be correct.

Not on his '98. Ford did away with the VSS on the '98 and up and started using the RABS to get the speed info. The only way to correct the speedometer on the '98 and up is to actually hook them up to a computer and reprogram it.

 

[cantspell]

so are you saying that when they do this re-programming, it correcxts the speedo too?

 

[Robert]

Yes, but finding a dealer willing to do it can be difficult since most dealers look at it as an emissions modification which they are forbidden by the government from doing. Some people have had to go to several different dealerships before they found one that would be willing to do it or even knew what they needed to do. The dealers that have been willing to do it typically charge an hours labor at their current rates.

 

[cantspell]

i work at a budget rent a car, and we work closly with a ford dealer, however i actully think/feel that the truck operates better, it seems to downshift better, especially at higher speeds, when ordinarily the truck will not down shift...and i swear i'm getting better milage, but my trucks been out of commision for over a week now...we'll see.