Speedo off

[Piranhaz]

I searched some past posts, but didn't really get the answer I'm looking for. I bought my 99 Trans Am a few days ago and the speedo is off by 10-12 MPH (higher than I am really going). It has the correct size tires on it so I'm not sure why it's off. I do not know the previous history of the car but I'm assuming everything is stock as far as gears etc. What can I do to get the speedo to read the right MPH?? Do I need to take it to a dealer???


Thanks


Chris

[Too Fast]

Sounds like somebody put different gears in it, like from a 2.73 to a 3.23 or something. You can have somebody fix this with a programmer like Diablo, or if you know someone with an HP Tuners software or LS1 edit, if you know what your current gears are.

Most dealers would probably be clueless, but call them and ask if you want to.

[screaminbird]

i was just goingt o say the exact same thing

[Piranhaz]

Sounds like somebody put different gears in it, like from a 2.73 to a 3.23 or something. You can have somebody fix this with a programmer like Diablo, or if you know someone with an HP Tuners software or LS1 edit, if you know what your current gears are.

Most dealers would probably be clueless, but call them and ask if you want to.

The car is supposed to have 3.42 gears as far as my code tells me. I'll have to verify that and go from there.


Thanks guys


Chirs

[Too Fast]

6-speed, eh? Nice. Sounds like somebody put in 3.73 or 4.10. If the gears are not making much noise, I would definitely keep them!

[Piranhaz]

6-speed, eh? Nice. Sounds like somebody put in 3.73 or 4.10. If the gears are not making much noise, I would definitely keep them!

Yeah! I was looking for awhile and really wanted a manual. I'll check it out tomorrow and see what gears they are. I'm curious now too.


Chris

[thearborbarber]

Jack up rear and count the number of time the driver shaft turns while you rotate a rear tire one time. Then you know your rear end ration.

[Piranhaz]

Jack up rear and count the number of time the driver shaft turns while you rotate a rear tire one time. Then you know your rear end ration.

Yeah, that's the way I usually do it. It gets you close enough to figure it out anyway!

Thanks


Chris

[Too Fast]

Easy to do with a normal clutch type limited slip, but my torsen works differently, loose until it feels the torque, always pulls both tires straight, right or left.

And yeah, 6-speed FTMFW! That is why I sold my '98 TA, it had an AT with 2.73.

[Piranhaz]

Easy to do with a normal clutch type limited slip, but my torsen works differently, loose until it feels the torque, always pulls both tires straight, right or left.

And yeah, 6-speed FTMFW! That is why I sold my '98 TA, it had an AT with 2.73.

OK, I'm confused. I'm getting about 2.25 revolutions of the driveshaft per 1 rev. of the tire. This would = about a 2:23 gear ratio?? Can that be possible?? That's not even an option as far as I know. Am I doing something wrong here???

Jacked up the car and tried turning the driveshaft but the wheel I was counting would slip and the other would turn. So I lowered one side to lock it and then turned the driveshaft to get the free wheel to turn and came up with this ratio. Is that really coming out right though???

Maybe I'll just have to pull the cover and check it out.

Any thoughts???

[Too Fast]

You could use a helper, she could keep the other wheel turning the same as the one you are turning so they both have the same rotation and count the ratio that way. Or, like you say pull the cover and do the count, this way you can know when the last time you had new synthetic fluid put in.

[Piranhaz]

You could use a helper, she could keep the other wheel turning the same as the one you are turning so they both have the same rotation and count the ratio that way. Or, like you say pull the cover and do the count, this way you can know when the last time you had new synthetic fluid put in.

Good point, probably just better off pulling the cover and putting new fluid in anyway. I don't know the history of the car.

[96Firebirdformula]

Here easy was to figure out what gears you got. Just click 98 M6. Then look at RPM in the gear.

http://www.f-body.org/gears/

[Piranhaz]

They are 4.10's!!!!


Chris

[Too Fast]

Nice gears for a 6-speed. Did you get your speedo calibrated yet?

[Piranhaz]

Nice gears for a 6-speed. Did you get your speedo calibrated yet?

Yeah, everything is good to go. Got the Skip shift removed too, boy is that nice!!!

[Too Fast]

I put in a SLP skip shift eliminator, I like it because when I see the skip shift light come on, I can either go into fourth gear or give the light the finger. Usually I give the light the finger!

[Boomer Sooner]

Here easy was to figure out what gears you got. Just click 98 M6. Then look at RPM in the gear.

http://www.f-body.org/gears/

why no 99 a4 f-body?

[bballking_2007]

CUZ the a4 has four gears and the m6 has six gears! lol it would be WAY off.

[Boomer Sooner]

duh.