What rear end gear should I choose for a 6.0/4l80 swap in my 02 RCSB 2wd? I’ve got 29.7” tires on 20” wheels. Truck Norris cam and I’ll probably choose a 2800 stall. I’ve been told everything from 3.73 to 4.56 since the 4l80 is geared higher in first gear compared to the 60e. Any thoughts?

 

The difference in 1st gear ratio between the two transmissions actually doesn't matter too much...the 4L80e has a tighter ratios between gears, and a slightly numerically higher 4th gear ratio, so it actually makes up for the "bad" ratio of first gear...you follow me?

​​​​What cam and torque converter stall speed do you have? 3.73 or 4.10 would either be good for a fun daily driver. Aggressive cam + higher stall speed converter can benefit or require a numerically higher gears, depending on what you have.

Also, what kind of driving are you doing? A daily driver is very different from a dedicated track vehicle. I'm assuming this is more like a street driver/spirited truck?

 

yeah it’s just a street truck at this point. I was thinking I would do 4.30 gears if it wasn’t going to mean 2500 rpms at 70mph. What do you think it would be turning at 70? Anyway to know? Thanks for the help.

 

Oops, I missed where had mentioned the cam and stall speed. Doh!

Look at this website and play around with the ratios, RPM and speed:
https://spicerparts.com/calculators/...rpm-calculator

4.30 would be pretty sweet for just driving around town. If you do a lot of highway cruising, you may consider 4.10 or less.


2500 RPM at highway speed is really not that bad TBH.

 

4.10s

 

Thanks for this tool. After messing around with it I think I’m gonna do the 4.30 gear after all.