I was driving my 1997 blazer to work yesterday about 1 mile down the road I took a right turn and suddenly lost forward all gears and coasted to a stop thr truck has no 1234 or R no bangs booms or slips previously it just quit. I towed it back home checked fluid first ok not burnt or foamy so I replaced multi switch and ignition switch same problem no change before I spend any more dough does anyone have any ideas where to go next I have multiple codes PO740, PO785,P1860 all mention solenoid circuit any ideas what and where to test for repair 154K on truck 4WD buttons work also worth mentioning the truck was quite sluggish almost like no passing gear for a lengthy time period but would sometimes come back to life on some occasions and run pisser maybe it's some kind of bad ground somewhere any help or good ideas are welcome thx mike. 1997 chevy blazer LT 4WD

 

It's not going to be electrical. The trans will move if able with no electric to it. Sounds like the pump rotor has broken. Very common problem. Have you tried to move it in 4x4LOW. Will it hold in park and not roll away?

 

It does hold in park and it won't move in 4WD high or low any way to test

 

Clutches prob danced their last dance. I'd drop the pan and see how that fluid looks. Then rebuild it with a monster transmission kit.

 

To lose everything at once like you did I would suspect a broken pump rotor. Very common failure. Will require transmission removal. Way to double check pump failure is to remove lower trans cooler line from radiator and put down in a container and start vehicle and see if fluid flows out. No flow =broken pump.