hey there so i just dropped a newer 4.3l into my extreme a couple weeks ago. i have finally had the time to finish it up, went for the first text drive to make sure everything was working properly. she cranked over just fine. but when i went to put it into gear, it was great but then i gave it gas to accelerate she won't move... But it will role in neutral just fine with no problem. and with keep it from ruling out of park like it is supposed to but won't turn the drive shaft for me to move at all. tried it in every gear. put 11.5 quarts of tranny fluid in asa directed but can't figure out why i can't get it to move.. any suggestions where to start. and i did replace the back up neutral safe with due to the swap i cracked my older one.

 

this is gonna sound dumb but did you hook up the converter to the flex plate ?

have you checked the fluid after putting it into all the gears?

 

Yes I did. I also checked the fluid while it was in every gear and says it full. The engine starts right up no hesitation, it just the truck won't move. I was having problems with my starter a few weeks ago. All I did to fix that problem was to take starter cleaner ( they actually sell cleaner just for your starter) and then she was good as no but still not wanting to move

 

Did you have any problems bolting up the bellhousing to engine?
Look at AT fluid level engine off. Then start and run engine, wipe the stick, look at it again.. Is it different?

Did you make sure the trans wiring harness is connected?
Did the trans fall, possibly stretching or hanging on wiring harness?

And last but not least...
does your 4wd have a 'Neutral' position?
Like, say 'Autotrac' feature?
https://www.google.com/search?q=2001+blazer+autotrac

 

i had no problem bolting the bell housing to the block, and done check it, it is cherry red and reading full. no difference in fluid when running or when engine is off.
i went out this afternoon to double check everything is hooked up properly and i found to ground wires just sitting on top of the bell housing. going out tomorrow to find a place to bolt those to, due to the fact they don't really reach any to bolt up to.
no the transmission didn't fall, just to make sure it didn't we had to people lift it.
and its 2wd so i wouldn't have that option of 4wd neutral.