92 gmc L80E4 wont shift

[rdykstra]

I own a 92 gmc 1-ton van. 6.2 with electronic trans. I can make it shift to the next gear by reeving up the engine. Acts like its towing but its not. Thanks for any help

[ 10-29-2004, 02:19 PM: Message edited by: rdykstra ]

[Keith Richards]

Has it been long since a fluid and filter change?You should flush it out.May be a longshot but a dirty filter can cause those symptoms.I always star simple and go from there.It's a good chance to see whats happening in there when you drop the pan too.Metal,debri,etc.

[rdykstra]

It started not shifting almost overnight. It seems to be a sensor or something to me.trans about a year old might have 40000 miles on it. its a rebuilt.last one had bad pump. wish I had schematic or a good manual to ck sensors.