73-87 Chevy _ GMC Trucks => Engine/Drivetrain => LT/LS Swaps => Topic started by: Tex 75K10 on October 29, 2019, 10:29:55 AM

Title: 5.3/4l80e/np241 Question
Post by: Tex 75K10 on October 29, 2019, 10:29:55 AM
Hey y'all, im getting a 4l80e from a 01 and im trying to hunt down a 241 transfer case (passenger drop), i've found a few but had some questions first. I found a 241 from a 88 model and i think its mechanical speedo, will i be able to bolt it right up to a 4l80e? If i can what are the steps to changing it from the mechanical speedo to the vss for the transmission computer.

Going in a 75 k10 lwb
Title: Re: 5.3/4l80e/np241 Question
Post by: frotosride on August 08, 2020, 09:10:06 PM
The 241 came in two flavor a and toppings, toppings were drivers side drop and passenger side drop. Then splines are the next differences, 27 spline for 700r4 and 4l60(e) 32 spline for sm465, th400 and the one you want 4l80. You can find input shafts to make a 27 spline I to a 32 from several places.
 VSS: the 4l80 normally uses 2 VSS sensors a high pulse and a lower pulse rate. To keep things simple you can keep either of the two sensors and that will allow the engine to run when in gear. The ECM has to see a VSS signal when in gear or it will stall. The output speed sensor of the transfer case depends on the year of the np241. Later years have a tone ring installed and an actual VSS installed. Early np241's still have cable driven outputs.
In either case the hardest would be an earlier model adapting to an OEM speedo.
If you wish to retain cruise control then you will need a high pulse rate 8k(+) on the output of the transfer case. Dakota digital and several others make an adapter that allows cable driven outputs to send a VSS signal and retain cable speedo hookup.