3.91 gear install and trans tune? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

kirkmfg · 11-10-2021, 07:31 AM

I have a 2015 SS auto with CAI, Kooks long tubes and tuned by Steve @ RDP. I am looking to install a 3.91 gear and the shops are saying I will need to recalibrate the speedometer which I understand. they are also saying I will need to reprogram the transmission or it won't shift right. Can someone explain what that means? I assume that is something Dyno Steve can do.

SSammy · 11-10-2021, 08:55 AM

I’m no tuner and hope anyone corrects me if I’m wrong, but I think the 6L80 WOT shift points are set to a certain mph. A change in gearing also changes the way your torque converter responds & flashes, because the gearing changed the amount of force required to get your car moving. Dynosteve can definitely calibrate for the changes, and can also give you a smarter explanation.

1JEWLDSSRS · 11-10-2021, 09:29 AM

Yes, you will need to re tune your trans for the swap, and Dynosteve can do that for you, and if you have his "tune for life", it won't cost you anything. The WOT shift points will need to be changed as well as the normal driving shift points, depending on your mods, as the new gearing will make things happen sooner in the rpm range. Also the speedo needs to be recalibrated for the new gears, as well as the converter lockup points. Good luck and enjoy the new "quickness"..

1JEWLDSSRS · 11-11-2021, 08:53 AM

Quote:

Originally Posted by dynosteve

yes i can do that for you sir

And there he is!! Nice...

11-10-2021, 07:31 AM	#1
kirkmfg Drives: 2015 Flash ss Join Date: Feb 2020 Location: illinois Posts: 6	3.91 gear install and trans tune? I have a 2015 SS auto with CAI, Kooks long tubes and tuned by Steve @ RDP. I am looking to install a 3.91 gear and the shops are saying I will need to recalibrate the speedometer which I understand. they are also saying I will need to reprogram the transmission or it won't shift right. Can someone explain what that means? I assume that is something Dyno Steve can do.

11-10-2021, 09:29 AM	#3
1JEWLDSSRS Drives: 2011 SS-RS Join Date: May 2011 Location: FLORIDA Posts: 11,485	Yes, you will need to re tune your trans for the swap, and Dynosteve can do that for you, and if you have his "tune for life", it won't cost you anything. The WOT shift points will need to be changed as well as the normal driving shift points, depending on your mods, as the new gearing will make things happen sooner in the rpm range. Also the speedo needs to be recalibrated for the new gears, as well as the converter lockup points. Good luck and enjoy the new "quickness".. __________________ TSP STAGE 3 CAM,231/246 @112 LSA 614/641 LIFT, CIRCLE D 5C-4200-4500 CONVERTER,LOD INTAKE.CORSA EXHAUST. DSS 1 PC DS. PEGASUS SOLID CRADLE MOUNTS. 486RWHP/475RWTQ.LOTS MORE.

11-10-2021, 08:55 AM	#2
SSammy Drives: 2015 2SS A6 Commemorative Edition Join Date: Nov 2019 Location: Utah Posts: 433 View My Garage	I’m no tuner and hope anyone corrects me if I’m wrong, but I think the 6L80 WOT shift points are set to a certain mph. A change in gearing also changes the way your torque converter responds & flashes, because the gearing changed the amount of force required to get your car moving. Dynosteve can definitely calibrate for the changes, and can also give you a smarter explanation.