Before & After - My 1993 K1500

blazerbrad · 07-06-2015, 01:00 PM

Sounds like the issue is because it does not know the t-case is in 4 low.

With the speed sensor on the trans lets say that when in high range, third gear (1:1) in the trans, and 2,000 engine rpm the speed sensor sends out a signal that equates to 45 mph. You now shift into low range, third gear in the trans, and 2,000 engine rpm and the speed sensor sends out the exact same signal and makes the ECM think you are still going 45 mph. However since the t-case is in low range the vehicle is actually only going about 16 mph (2.72 times slower...or about 3 times).

Do you still have the VSS on the tailhousing of the t-case that you could hook up?

07-06-2015, 01:00 PM	#9
blazerbrad - CORE Member - Join Date: Feb 2007 Posts: 831 Images: 6	Sounds like the issue is because it does not know the t-case is in 4 low. With the speed sensor on the trans lets say that when in high range, third gear (1:1) in the trans, and 2,000 engine rpm the speed sensor sends out a signal that equates to 45 mph. You now shift into low range, third gear in the trans, and 2,000 engine rpm and the speed sensor sends out the exact same signal and makes the ECM think you are still going 45 mph. However since the t-case is in low range the vehicle is actually only going about 16 mph (2.72 times slower...or about 3 times). Do you still have the VSS on the tailhousing of the t-case that you could hook up?