[SSLR]

I have a 2000 Sierra 1500 with a 4.3l Vin "W". I recently swapped the transmission with a S10 2002 transmission. Both are 4l60E swaped the bell housing and tailshaft seem like a perfect fit. Oh and I changed the fly wheel to. The only reason torque convertor bolts were alighned to the old fly wheel different. Took the fly wheel of a 2002 S10 "W" 4.3L MOTOR perfect fit. So everything is bolted up. My problem is starter will not turn over! Replaced starter replaced all grounds and possitive battery cables still nothing. Turned engine by hand nothing locked up. And when i turn the key I hear the starter rely click on and off.Neautral saftey switch?? are they different internally? all wiring pluged up no problem....

[poncho62]

If the starter clicks, the neutral switch is working.....Take the starter off and test it on the bench. Either its a bad starter or the starter is not lining up right and jamming....but, they usually grind when that happens

[SSLR]

I already replaced the starter. Relay clicks not starter...

[Two8tyThree]

If starter solenoid is OK. Check Battery cable, may have a bad end on it or the cable has an internal break. Don't forget to check battery ground cable also.
Is the battery fully charged?
With the starter out of vehicle will it work if you use jumpers cables, positive to positive stud and negative to clamp on starter use a screwdriver to jump the solenoid.

[dinger]

I would also check the gap between the flywheel and the starter, does it extend far enough to engage. I know nothing of this matching of parts, is it possible you have the flywheel on backwards? Can you lay underneath the truck and have someone hit the key while watching the starter. Also does the solenoid engage all the way?