95 gmc suburban tranny probs . intermittently the abs light comes on speedo on 1995 GMC Suburban 1500

driving the abs comes on then the speedo goes to 0 and it feels like I'm in neutral I slow down and have first gear and can sometimes get it to manually shift in to second go for third and get neutral? no codes pop up any ideas?

by in Harrisburg, MO on December 09, 2011
1 answer 2 comments
ANSWER by on December 09, 2011
The vehicle speed sensor and/or wiring is a good start.
COMMENT by on December 10, 2011
I swapped out the speed sensor and the wire appears to look in tack is there anyway to test the wire? Looking in my haynes book and it shows a speed sensor buffer which appears to connect with the speedo,abs,and tranny any possibility that could be the problem?
COMMENT by on December 10, 2011
Basics first: make sure battery cables are completely clean and all vehicle ground connections are good and the alternator isn't acting up. Then check for related TSB's that may address this issue. Domestic vehicles often require computer recalibrations, but more so on newer models (1996 up with OBD2 diagnostics). A digital volt/ohm meter is needed and leads long enough to check from sensor to computer. Be sure to check all connectors; clean or replace as needed and sensure terminals have positive engagement. A shop with a lab scope can verify the speed sensor is outputting an acceptable wave form (at the computer) or possibly with a scanner (OEM/Dealer type). Also, not all sensors are created equal and may require using the dealer part.

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