Roadrunner 45

iTrader: (1)

After doing a search, there seems to be two opinions out there on the need to reflash the PCM to a M6 when going 4L60E to TH400.

1- You "must" do it. The PCM will not use the correct timing/fuel curves if this is not done.

2- It's optional- the SES light will be on, but the car will run fine and the PCM will use the correct curves. A reflash will just turn off the SES.


Who is right??

Roadrunner 45

iTrader: (1)

c'mon guys- no one knows the answer to this?

LS1x2

iTrader: (11)

It will not effect the fuel and timing if you don't reflash it. I stuck with an a4 tune for a while when I went with a th350. I atap'd and saw no change in a/f or timing.

DERTY

If you don't mind the speedo being off you will not need it reflashed. However, you will ultimately need to reflash it to at least correct the gear ratio or the 160MPH max speed will kick in and shut the engine down at a much lower speed. The engine settings will be fine otherwise. You would benefit from a retune, but not by huge amounts.

Roadrunner 45

iTrader: (1)

thanks for the replies. About the speedo issue, I added the reluctor and magnetic pickup to splice into the stock harness. The speedo seems to be working fine. Will I still have this "shut off" issue?

Ryan

DERTY

If the speedo is accurate you will not have an issue. If it is not it will run into the shut off MPH limit. Since it appears to work in your case it should be fine.