Should I retune after installing 4.08s ?
 

:hello:

I did a search on here and google, without definitive results.

Is a retune recommended / required after installing 4.08 gears to get the most out of them? or can I just plug and play?

Thanks,

I have not researched but how do you correct your speedometer on a Z after a gear ratio change? Is it mechanical or corrected in the tune?

Plug and play. It won't change how the engine was tuned.

If you have rev matching then you'll need a tune to get it working along with the cruise control.

Speedometer doesn't have anything to do with gears, it's based on abs sensors on the axles.

Good to know. I was thinking about my old Jeep with a speedo gear on back of the Transfer Case.... Old school tech!

I've read the SRM goes out only if you track the car over 120+ mph with the 4.08s. Then you have to shut it down wait for a few minutes and turn it back on and it's working again. Also read its only going to be off by 2 or 300 rpms when it does work.

Cruise control I've read is hit or miss whether it will work with the 4.08s or not. Z is not a DD so no biggie either way.

Edit: CC works with 4.08s IF you have a manual. AT with 4.08 needs a tune to get the CC to work.

This is what I've read from various sources within the Z/G community forums across the net. Everything I'm reading could be dead wrong of course but this is what I'm seeing from people who've done this to the Z's/G's with the VHR and AT or MT.