2001 Speedo Off by 7mph :o

[HK-DEMON-]

Long story short, I ended up switching my OEM gear ratio to accommodate my 24" wheels. I decided to go back to OEM stock 20"s now my gear ratio is way the F*&ck off.

How can I fix this?

Thanks.

 

[SC88]

What gear ratio did you go with? You can have someone go into the computer and change the gear ratio and tire diameter to match so your speedo is accurate.

I used HP tuners to adjust my speedo for the 26s

 

[HK-DEMON-]

What gear ratio did you go with? You can have someone go into the computer and change the gear ratio and tire diameter to match so your speedo is accurate.

I used HP tuners to adjust my speedo for the 26s

To tell you the truth I don't remember the gear ratio I went with

Is their any other programmer I can use?

Thanks for the input

 

[The 'ER]

Programmers suck go to black bear performance and they are a supporting vendor spend the cash and do a new pm and be done with it. As far as the gears did you order it from a shop or online? U can call the company you ordered it from with the order number and ask them.

 

[SC88]

To tell you the truth I don't remember the gear ratio I went with

Is their any other programmer I can use?

Thanks for the input

To change the ratio you can use LS1edit, hand programmers like hypertech or diablo

but like mentioned already you can have BB do a tune for you and fix it but it will be pretty hard if you can't remember your gear ratio that is very important.

 

[HK-DEMON-]

Does any one know the OEM gear ratio that came with the 2001 Chevrolet Tahoe?

I found out the current gear ratio for my Tahoe, its 3:73. The tire size spec is 275/45R20, so making the tire size diameter 29.7". But does any one know

Why my speedo is waaaaaay the **** off?

 

[SC88]

Look on your glove box door for the gear ratio code for your truck. My moms 03 tahoe has 3:73s and my 04 does as well.

look for code GT4 (Third row down 2nd to last on the end going from left to right.) That will tell you what it came with from the factory.

and I calculated your current tire diameter at 29.74 (275/45/20)

Stock for mine was 30.60 (265/70/16 tire) Gm has it coded into the computer as a tire diameter of 29.77

So its not nearly enough that it should throw off your speedo like it has. I would check the current programming and see what they have your ratio and tire diameter at.

 

[HK-DEMON-]

Look on your glove box door for the gear ratio code for your truck. My moms 03 tahoe has 3:73s and my 04 does as well.

look for code GT4 (Third row down 2nd to last on the end going from left to right.) That will tell you what it came with from the factory.

and I calculated your current tire diameter at 29.74 (275/45/20)

Stock for mine was 30.60 (265/70/16 tire) Gm has it coded into the computer as a tire diameter of 29.77

So its not nearly enough that it should throw off your speedo like it has. I would check the current programming and see what they have your ratio and tire diameter at.

I have code K34.

I also have the tow package which perhaps might have to do something with it.

I also found a code with a "G" its GU6, no other codes with a "G".

 

[SC88]

Ok your on the right track. The "K34" is for the cruise control option.

The GU6 is the 3.42 gear ratio and now you have the 3.73s so you need to have the computer changed to accomidate the new gear ratio. The 24's themselves assuming you went with a 305/35/24 tire would of thrown your speedo off by 5mph @ 60 so you would of actually been doing 65.

You need to go back to 3.42's to get your speedo back right assuming you didn't change it through the computer when you did the switch. If you don't want to do that call up a local tuner or BB and have them adjust your PCM for the new changed.

 

[HK-DEMON-]

Ok your on the right track. The "K34" is for the cruise control option.

The GU6 is the 3.42 gear ratio and now you have the 3.73s so you need to have the computer changed to accomidate the new gear ratio. The 24's themselves assuming you went with a 305/35/24 tire would of thrown your speedo off by 5mph @ 60 so you would of actually been doing 65.

You need to go back to 3.42's to get your speedo back right assuming you didn't change it through the computer when you did the switch. If you don't want to do that call up a local tuner or BB and have them adjust your PCM for the new changed.

Thanks for the info bro.