SO where to begin ..... o yes bought a new 4.3l long block (after serious overheats by wife) changed everything over installed new motor got it started AND running fine. Did a final check on all fluids (and they were all good oil tranny power steering cooling even brake fluid) put the hood on then skid plate mind you the blazer was running this whole time got ready to take the test drive got in put on seat belt adjusted mirrors put it in reverse and WTF!!!!! no reverse no forward it acts as tough it is in neutral in all gears in fact with it running and in a gear. You can push it as if it was in neutral no resistance what so ever and yes the tranny is full of fluid to the top of the add line yes it worked fine before the engine swap. Never had any problems with it. the neutral safety switch is working fine. ie; only starts in park or neutral back up lights come on in reverse brake lights work when pushed does any and i do mean any one have and %^#$ING idea whats going on or had this problem themselves. About the only thing i did not do was to completely fill the torque converter before installing it but it was filled about halfway as to avoid loss of too much fluid in my garage.please help I'm at a serious loss and my wife is on my *** for her beloved blazer being down this long .

 

Is it 4wd? If so, did the transfer case get shifted into neutral somehow? Does it move even when in park?

 

if you pulled the engine with the tanny still attached, did you reconnect the driveshaft/s? it's probably the transfere case in neutral though, like swarlkk suggested.

 

Did you bolt the torque converter back to the flexplate?

 

the shift selector for the transfer case is push button type and when pushed to select 2H 4H 4L you can hear it engage so i do not believe its in neutral as far as the driveshaft yes its in and the torque converter is bolted to the flexplate as far as moving while its in park i will check never tried that.

 

you say you here the transfere case engage, do you here the tranny engage when you shift ? if not, maybe your shift linkage is disconnected.

 

shift linkage is definitely connected when you shift the tranny into gear the engine idle does'nt change like it isnt shifting into any gear it has been suggested to me that when i installed the tranny to engine that i may have broke the nubs off of the front pump in the tranny so it isnt pumping fluid at all not allowing me to get any gears it has also been suggested that maybe the neutral safety switch which also sends signal to the actuators in the tranny may be bad.has anyone had any expierience with either of those things im not much of an automatic tranny guy always had manuals myself.

and no you dont hear or feel anything from the tranny when its shifted into gear.

 

If it still rolls in park and the transfer case is definitely not in neutral, then you have internal problems in the transmission.

If it doesn't roll in park, then the transfer case is engaged properly and the park dog in the transmission is working properly. The next thing may very well be the pump in the trans. To see if this may be the case, pull one of the transmission cooler lines and direct it into a bucket (using some additional hose on to both the outlet from the radiator & the line). Start the engine. If you do not get fluid out of one of the lines, the pump is not working.

 

^^^What he said.....also how did you install the torque converter??

Did you bolt it to the flexplate first then install the tranny.....or did you install it on the tranny first, bolt up the tranny and then install the flexplate bolts??

 

Did you fill trans fluid with vehicle running? Converter holds more than 4 quarts alone plus around 6 in the pan. It could be that you are still low enough that nothing is happening. I've rebuilt/installed at least 6 transmissions and am still surprised that I never have enough fluid in the first time. One thing I always do it pull the dipstick and listen. If you hear gurgling you are WAY to low on fluid and the pump is sucking air.

I would first start by verifying everything else that has been stated. If it worked when it was removed, then there really shouldn't be any excuse for it not to work when reinstalled. Unless something was done incredibly wrong aside from lack of fluid.

Does anything happen if gear selector is moved into 1?