4WD Guide

Looking to do an LS or LT swap on your 4WD vehicle? This guide will help get you the information on getting the right parts and how to make your 4WD system work in your chassis!

There are two main types of transfer cases used in swap applications, electronic transfer cases (push button 4WD) and mechanical transfer cases (floor shifter). Push button GM transfer cases are currently not supported directly within our harness, however there are systems out there that are considered standalone to integrate them (something we are looking to support in the future). 

Transmission Speed Sensor

As far as mechanical transfer cases go, the only aspect that gets integrated is a speed sensor. The 4L60E and 4L80E both have speed sensors on the tail shaft of the transmission. This means when they are converted to 4WD, the speed sensor is removed from the transmission itself and relocated to the transfer case. Newer transmissions including the 6L80/90, 8L80/90, and 10L80/90s will read vehicle speed directly in the main transmission connector, not on the transfer case. 

Transfer Case Speed Sensor

Transfer cases will either have a mechanical speedometer cable on them (NP205, NP208, etc) or they could have an electronic speed sensor on them (NP241C). Transfer cases with mechanical speedo cables on them will need 2 products to give the correct output signal for the LS computer: the pass through pulse generator, part # SEN-01-4160, and a converter box part # SGI-100BT. The pass through pulse generator can also be used anytime you want to retain a factory style cable drive speedometer, as this will allow the hookup of a factory speedo cable. If a mechanical speedo cable will not be used again, you could use 1 product instead, the 128k pulse generator part # SEN-01-128. This will take the place of both the pass through generator, and the converter box. LS computers need a 128k pulse signal for the computers speedometer to be calculated correctly. 

If the transfer case that is being used has an electronic speed sensor already like most 1990+ GM transfer cases, then the speed sensor plug on the harness might just need to be switched out for the correct one for your t-case. PSI uses a standard speed sensor plug and we do not use specific transfer case plugs. If the transfer case does not output a 128k pulse signal, then you can either use the SGI-100BT converter box, or custom tuning may be required.