Question about 3.42 Gear Swap..??

[Texas4ever]

I know this question has been tossed around before and I have checked the Mod Encyclopedia.I know it says that if you go from 3.08's to 3.42's the best to correct your speedo you either need to buy a Jet SCU or get your PCM re-programmed.

My question is what has been your experience with both of these solutions, so I can decide which would be better for me. I am getting a Posi diff and some 3.42's installed just as soon as good 'ol Uncle Sam will cough up the cash..!!

The dealership said they would upgrade the PCM for $120 to correct the speedo with the gears. I am just wondering if the Jet SCU may not be a better choice because I would have more control over the shift points, not to mention it will remove the top speed limiter on my V6.

I have been reading this board for about 3 months now. You guys seem to have some really good input and know a great deal about our cars.

This is my first post to the board. Just looking for some first hand knowledge of my options to make the gear change as clean and useful as it can be. [img]smile.gif[/img]

[LimitedE]

I swaped from 3.08's to 3.42's and my speedo is about 10mph off. I didn't think there was any aftermarket device that could interface with the ECU on a '97

I wouldn't suppose the dealer would be willing to remove that limiter also would they? :D

[Nachius]

I have a 96! I went from 3.08s to 3.42s with the SCU2000. It works you have to mess with a ton to completely correct shift points but by that time your speedo is off again!

My opinion is if you can get a deal to reporgram yoru computer DEFINATELY do it! It will be worth it in the long run!

[Texas4ever]

Nachius,
Are you saying that the shift points are only controlled by the RPM of the engine..?? I thought is was a combination of the RPM's and the speedo which determined the shift points..??

LimitedE,
You say your speedo is off by 10 MPH, I probably could live with that, but does your tranny still shift at the correct RPM's...??

thanks...

[camaro_zach]

pcm hands down. if it was a manual it wouldnt really matter cause you shift it, but with an auto it makes a huge diffrence.