Speedometer off after new trans

[jcd9730]

After putting in a 2004r, it seems my speedometer is off. I havent checked anything, but its pretty obvious when Im blowing by every car on the road and the speedo says Im under the speed limit

I had BTO put the right speedo gears in the trans, and gave them my gear ratio/tire size. But it still seems off.

What can I do to test and fix this? Kinda at a loss here

[slow-1]

I had to change gear several times before getting it right. BTO was very good about exchanging gears with me until it was right.

Use a gps to check to see how far off you are and give BTO the info, they will get you straight.

[68gmsee]

Originally Posted by slow-1

...Use a gps to check to see how far off you are and give BTO the info, they will get you straight.

That's what I did to check the speed on my 68 after exchanging driven gear to get the right speed. First I checked to make sure the GPS was accurate by testing it with my Trailblazer. It was right on the money at several speeds (I have two GPS's and both were exact).

[jcd9730]

Oh I didnt even think about GPS.

Did you have to take the trans to bowtie and have them change the gears?

[MusicMan70]

Art Carr sells a speedo correction unit...scroll down a bit.

http://www.cpttransmission.com/

[slow-1]

Originally Posted by jcd9730

Oh I didnt even think about GPS.

Did you have to take the trans to bowtie and have them change the gears?

Just remember with GPS, it is giving you your average speed so as you accellerate and decellerate the GPS speed will lag behind a bit...so to be most accurate drive at a steady speed.

Gear change is easy, just one bolt to pull the housing the speedo cable goes into.
Posted via Mobile Device

[68gmsee]

Originally Posted by slow-1

Just remember with GPS, it is giving you your average speed so as you accellerate and decellerate the GPS speed will lag behind a bit...so to be most accurate drive at a steady speed.

Gear change is easy, just one bolt to pull the housing the speedo cable goes into.
Posted via Mobile Device

Yeah, I drove at 20, 30, and on up to 70 for a few seconds on each speed. The driven gear is easy, the drive gear may be a little more difficult if you have to change that one. Every transmission is different.

When you do remove the bullet, notice the color and maybe count the teeth of the internal drive gear. That way you can have some way to match the gears and/or let the vendor know what you have.