If i am running the nelson tune that is set up for the 4.10 gears and now switch to 3.73 do i have to retune or can i run it like that

 

I dont think it will matter. The mph will be off but it shouldn't be a big deal

 

your speedo and odometer will read 5-10% low. Meaning, when driving 60 your speedo will say 53-54...if it is a drastic gear change it will cause havoc w/ the bcm and you will get ABS and brake codes....other than that, the it won't matter....You should see a little better mileage, and a little slower off the line...or did you switch to smaller tires at the same time?

 

no same tires but how about rpm like shifting points

 

No change...doesn't matter what the wheel speed is ... just r's and that won't change w/ changing the gears in the tune.

 

cool so i can go to the track this weekend and shift at the same r's as b4

 

it all depends on how it was set up. the r's are going to read different and will in effect cause the shift points to be off. the pcm uses speed as well as rpm to shift the trans.