Why won't the engine stay running when placed in gear on a 1996 Chevy pickup 5.7?

Answer 1

I assume this is an automatic transmission. If not, disregard this. Check the torque converter. Torque converters are the automatic transmission equivalent of a clutch in a manual transmission. Torque converters are basically fluid couplings. Once the engine revs to a certain rpm, the fluid inside the torque converter begins to turn the input shaft of the transmission. Below that rpm, the engine is able to spin without actually turning the input shaft of the transmission (not enough fluid pressure). Newer torque converters have a lock-up function that hydraulicly locks the torque converter to the engine to prevent slippage for better gas mileage. If the lockup doesn't release, it will cause the engine to stall if you are at a stop in gear (because the engine is trying to turn the transmission, rearend gears, and wheels which are being stopped by the brakes). There is a very detailed procedure for checking the torque converter lockup function at http://autorepair.about.com by Vincent Ciulla. Depending how mechanically/electrically inclined you are, you may or may not be able to do this yourself. The quickest easy-fix would be to go buy some Seafoam transmission treatment at a local parts store. However, this will only work if one of the valves in the transmission are clogged/stuck. But, the stuff is cheap, and easy to use, just pour it in the transmission dipstick tube. Hope this helps you. -Jason