crankshaft sensor?

Hello! I have a 2000 s10 pickup 4x4 with the 4.3 vortec. Has bout 140000 miles on well taken care of but today while driving transmission started slipping. At least I thought? I parked it when I got home called a mechanic friend he said bring it over. So driving over transmission shifted fine till right before I got there then started what felt like slipping again. Fluid is good and checked codes and it came up with crankshaft sensor code. Could a bad crankshaft sensor be causing this slipping feeling? RPM's go way up when "slipping" feeling occurs but this seems intermittent. Any help would be great!Thanks!!:banghead:

I think you hit it right with the transmission. Fluid and filter should be changed every 36,000 miles, how long has it been?

Fluid has always been changed at 30,000 intervals. Its strange since it has always shifted smooth and tight until today and even when it started today doesnt do it all the time. Could the crankshaft sensor be bad and sending the ecm false RPM readings causing the transmission to change its shift points? I dont know what sensors are in the transmission and if they react to information sent from other sensors for optimum shifting times?

Was the Service Engine Soon, (SES) light on when the slipping occured? What DTC was in memory?

Yes the ses light was on when slippage occurred and it did go out after awhile then came back on. But this has happened in the past when there wasnt a problem. Light would come on then go out and not come back on for a couple months. Never had ses light checked before cause it always went out again. Now that this problem started today I hope it wasnt something I let go too long? Everything was working great before today!

Whenever the SES light comes on, a Diagnostic Trouble Code, (DTC) is set. If it's an intermittent problem the light might turn off but the DTC is set in memory. There are two ways to remove it from memory: If after a pre-determined number of drive cycles the ECM does not see the same failure, it will remove the DTC from memory. The other way to remove the DTC is with a scan tool. What DTC was set on yours?