Rpms causing shifting too early....2012 Cascadia

Vehicle speed sensor bad .. speedo bad or rpm gauge bad .. no other way to lose road speed and have rpm down ..check your road speed against a gps app if it’s correct it’s the rpm gauge .. If it’s out then it’s in the speedo area or vss

 

lol, I didn't even consider an auto.

 

Sounds like he has one of those autoshift transmissions. Has a a clutch pedal and no gear shifter.

 

See that's the importance of giving people enough information to actually give a relevant answer. Never once did OP say anything other than "10 speed"

 

Ok so I see original post has been edited to say transmission is a manual.

So I'm really not understanding the question. Why are you shifting it earlier now? Just run it like you did before.

 

Delete changed rear ratio in ecm possibly or rpm gauge is wrong..

 

Ok I follow you now. Original post made it seem like something was telling you to shift earlier (or in the case of an auto, the transmission shifting too early).

If this started happening right after you did the thing we shall not speak of, I'd wager that some of the parameters in the flash file they used don't match the truck's specs.