08 F350 axle gears DASH / COMPUTER question... - Diesel Forum

RKRacing · 10-17-2007, 02:31 AM

37's on there and going with 4.30 gears(3.73 now)....all ready have the mph corrected.
Question: Will there be anything lighting up on my dash gages... any funny readings due to the gear changes? Any computer problems,THANKS!

RKRacing · 10-18-2007, 12:15 AM

Has any one changed their gears yet in a 08...

blkout2 · 10-18-2007, 11:54 AM

I went with 4.10 but didnt think it was enough so i am switching to 4.30 today should be on the road tommorrow

Toby4143 · 10-18-2007, 11:39 PM

Hey there i'm possibly looking for some 373 gears for my 08 due to the crapy milage, i have talked to the dealer and they told me they could change the computer setting for different gears.
My truck is an 08 dually.
Tobysmobilerepairsinc@comcast.net

ritschner · 10-20-2007, 02:54 PM

If the 08's are like the earlier trucks, which I believe they are, changing the axle ratio will have no affect other than RPM at road speed. The speedometer pickup is in the differencial and is induction ring is separate from the ring gear. If your speedometer is correct now, it will still be correct after a gear change. It only needs to be recalibrated after a tire diameter change. The only thing I would suggest is to reset the PCM to allow for the different loads that will occur at a given road speed. The PCM will eventaully learn on it's own, but it will probably be less frustrating to reset it. If you are worried about clock and radio settings, you can reset the PCM by removing the PCM keep alive fuse for twenty seconds. The fuse number will be listed in the owners manual.

Mercury · 10-26-2007, 01:25 PM

What u turn said is the same thing I would have said.

I am very familiar with the 99 - 08 superduty trucks and speedometer correction methods

to original poster: how are you correcting the speed by the way?

kenny