4l60 to 4l80 swap

[russj85]

Hey I have a 99 tahoe 4dr 4x4 and am interested in putting a 4l80 in it what all would be involved? I've heard some people say you lose your 4wd and have to lengthen the drive shaft and others say you can keep your 4wd but would have to shorten the shaft and lengthen the front shafts so I'm really confused. Any insight??

 

[willxfs]

Lots of good write ups on this if you google it. 4l80E is about 1.5 inches longer than 4L60E so rear drive shaft will have be shortened and front drive shaft will need to be longer. You will also need a larger input shaft on your transfer case as the output shaft of the 4L80E is bigger than the 4L60E. A few wires in the transmission plug/connector will have to be adjusted/moved around and you will need to run a new wire from the 4L80E's additional speed sensor to your wiring harness connector for your computer (under hood). Computer will need to be re-flashed also. A very worthwhile conversion in my opinion, especially if you tow heavy loads alot or plan to up your horsepower and torque with a higher output engine.