Need some help here folks. I have a 1990 C350 (4 door bronco) based off a F350 crew cab chassis, 460 with the e40d.


Finally got the bigger tires on it after a ton of work (radius arms and coilovers vs. leafs, shackle flip in the rear, blah blah blah).


Anyway, my problem. Transmission shifting schedule is all screwy from the difference in tire size to gear ratio, and I need to fix this.


Is this a simple speedo gear swap, or do I have to go into the computer?


Thanks.

 

Does the speed sensor for the transmission pick up off the speedo cable? In my reading, that's what it looks like.

 

If you truck has a cable driven speedo then there should be an electrical connection on the same device at the trans or t-case that feeds the computer, and if so you recalibrate both by changing the driven gear on the end of the cable. Which gear you need depends on which one you start with and how much of a change you need to make, but it's a quick/easy thing to do so even if you have to try a couple different gears it's not much of a job.