Spoke to a buddy of mine who manual swapped his 2005 and used his auto computer. He had the same issue, but unfortunately it took two different methods to correct. He was able to correct things like tire size and gear ratio with a tuner, but the revolutions per mile had to be changed in a custom tune built specifically for his computer. He used Fred from Rogue Performance, but this was 6 or so years ago so I don't even know if he is still in business, and I personally don't like his attitude (grumpy older guy) or his refusal to answer emails.

Another name I saw mentioned before was Don Lasota at Lasota Racing, but I never used them personally so can't really give any reviews.

I personally swapped the computer to a manual computer since it's easier on an 03. Never had to deal with any tuners other than the one I used to change my tire size and gear ratio in the computer since I'm running 35's and 4.88s.

 

Well if that is the case then you could use Dakota Digital SGI-100BT, $120: https://www.dakotadigital.com/index....od/prd1192.htm

These allow you to convert Ford speed signals up or down
Since its a 4x4 I would see if you can use it between the OSS sensor and Computer, i.e. change the Manual Trans OSS PPM(pulse per mile) output to Automatic PPM output, that way computer will speed correct in 4low
I would email or call them as this may have/should have come up before

Worst case is you can use it with OSS directly to speedo/odo and cruise, that's its normal configuration


Ford's standard PPM is 8,000ppm for speedo/odo and cruise, since the 1980's
If OSS on an automatic was 30,000ppm then computer converts it to 8,000ppm and sends it out
If Manual trans OSS was 25,000ppm then the conversion would be wrong of course

 

I'm that buddy, Sorry I didn't reply sooner.

I had the exact same issue with mine and i had to have the tuner manually dial back the tire size to accommodate the difference between the auto speed sensor and the manual's OSS. I wish i had known about the dakota digital thing that Ron posted, because that would have been a lot cheaper than the $500 custom tunes and tuner.

 

Thanks for the input I have spoke with a buddy of mine who is a mechanic and says he has a tuner and thinks he can sort it out