Rearend Change
#1
Rearend Change
I'm running a 9" Ford rearend behine an LS1 and 4l60E. I'm changing from a 3:70 ratio to a 3:43. I have Dakota Digital gauges so I can set the speedo but will I need to have the computer retuned? Thanks for any help, Neil
#3
Staging Lane
Join Date: Jan 2009
Location: Bella Vista, AR
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Shift Points
You may not be satisfied with your shift points verses throttle position unless you did not change them when you put in the lower gears in the first place. The PCM has tables that tell the transmission what speed to shift from each gear to the next. Most LS1 FBody cars with automatics came with 3:23 gears and if your shift points were revised when the 3.73 gears were installed you will find you car shifting very quickly (lower speeds than optimal). If only the Dakota was using to revise the speedo when installing the lower gear set, then your settings will be closer to correct when you go to the 3:43 (which was stock for FBody with manual transmission). If you are wanting performance you should stick with the 3:73 gear set, and if you are looking for gas mileage you should go back to the 3:23 gear set this engine and transmission combination GM decided upon.