Jeffk

My speedo has been off 10-12 mph since I bought the car. I assumed that it was because the car had 4.10's at one point but the guy I bought the car off of had 3.55's put in. I changed the gear oil so I know for sure they are actually 3.55's. Anyway, I had an SCT 3000 from my previous car and I ordered a mail order tune and the tuner left the gear/tire rev options unlocked. I know he set them for the 3.55's and the 315/35 rear tires but it was still off so I set the options myself...no change.

I read on the forum that after 98 there was no cable gear to change in order to recal the speedo to gear changes but I'm starting to wonder if the previous owner knew that.

Looking for any input on where to start to figure out why it's still off. Not that it's a huge deal but it was one of the main reasons I got a tune. The car ran well as it was.

Thanks,
Jeff

Jeffk

art02gt

do you have aftermarket overlays? Some people take off the needles to install them and can potentially position them in the wrong position when they put them back.

Jeffk

Stock overlays. Good thinking though Art

CPTCO

Are you high or low Jeff? Might take some time, but maybe by just playing with the parameters until you get close. Like plug in 3:73s or something. I know that doesn't really get to the root of the problem, but...

Jeffk

Its reading 10 lower than actual speed.

I guess I might have to just do it.that way Chris. Was more curious to see if there is a gear on the speedo.

CPTCO

Yeah, like I said, doesn't get to the root of the problem, but would at least work.

LilRoush

What are you using to confirm the actual speed of the car?

DeathRattle

How do you know they are 3.55s from just changing the gear oil? Maybe you're wrong about the gears in it.

Jeffk

It's stamped in the pinion gear.