I have 410s in my truck and I'm going to switch axles with a guy who has a set of 373s in his truck. He is wanting my axles so he can run bigger tires. I'd like to go to the 373s for drag racing and mpg.

My question is can the dealer change the info in the ECM so it knows that I'm running 373s ? Has anyone done this and if so what do I need to do? I don't know if this is the right way to do it. I would like to make the ECM right so the truck is like the factory build it with 373s.

CRIS

 

the dealer can adjust what they call the "pinion factor." not to hijack your post, but im in N.CA and would trade my 4.10's for 3.73's if anyone is interested.

 

I thought that the pinion factor was to do the tire size not the axle ratio. I was told that the axle ratio was in the ECM, but I might have been told wrong. I just want to make sure that the dealer can change what ever is in the ECM (store 373s in it) to make it like factory.

CRIS

 

There are no changes necessary in the ECM for gear changes. The speed sensor comes off the exciter ring and there is a different exciter ring for each gear set.

 

not to hijack either im in colorado and would like to trade my 3:73's for 4:10's.

 

yes, this is correct. I changed my ring and pinions out, and no electronic mumbo jumbo was needed

 

Were is the exciter ring at? Is it in the rear end on the gear or is it outside the housing? We were just going to change the axles from one truck to the other. By changing the axles will the 373s I put on my truck tell the ECM what they are?

CRIS

 

The ring is part of the carrier inside the axle. You don't need to change anything in the computer. The speed is calculated by the ABS tone rings if I recall.

 

why not just switch gears if you swap axles you might get a worn out front end bad brakes ect,ect,ect....

 

Its easier to change axles, besides just drive the other guys rig and make sure its all good to go.

 

Changing the axles is a better way to do this plus its less costly. As for the brakes I'm going to keep mine because they stay on the truck. My truck is a 05 and his is a 06. Both trucks have about 22000 miles on them.

CRIS