Have you tried rolling the truck or just turninng the rear driveshaft while it' in park?

If you can, might be a clue that it isnt the pump anyway. Then you would pull the tc and see if you can turn the trans output shaft.

 

here is what i have found. i can find no acuator with vacuum lines under the battery or on the drivers side behind the headlight which leads me to believe there is no activator. like an earlier post said, it appears this is full time 4wd so a vacuum line is not the problem. i did try to move the vehicle and found it will roll while it is in park. I have the rear drive line connected. i am not sure what this means. any info is appreciated.

 

When you say you have the rear drive line in, Does that mean the front one is out? If so, If you have a full time AWD that has a center diff in the t-case having the front shaft out will be the same as having the rear out. They MUST both be in! Its the same as lifting one wheel of a axle off the ground you get no power to the other. Now, there ARE AWD t-cases without a center diff...like the 126 Bravada case that electronically modulate a clutch sending power to the front axles..But I'm pretty sure what you has a viscous and a planetary (center diff) Was the front driveshaft in when you removed the old trans or any other things you tried to change while you where in there that might not have been mentioned? Is the trans swap job completely done or just bolted in enough to "TEST" Todd

 

hmm. hadn't really thought of that since my experience has always been with 4wd, not awd. everything is bolted in except the front drive line and the bottom of the bell housing, (inspection cover). i'll get to work.

 

sorry for the long delay in what happened. funny what happens when the vehicle you are working on is not a daily driver.

the advice i got was right on the mark. the front drive line had to be in.

i did run into a problem in the reassembly that i have not solved yet. the rear knuckle of the front driveline slightly hits the floorboards now. i have taken this apart and put it back together a few times looking for the secret. none of the mounts have slots. it seems it is about 1/2" to 3/4" too close to the drivers side.the transfer case is the same one i took out and so is the driveshaft. the trans to cross member mount is the same either way, it can't go on backwards. the driveshaft can only go on the way i have it. its the strangest thing. the cross member can only go on one way. looking for more good advice. it sure was good to see this blazer finally move on its own power. thanks

 

Glad you got it figured out! I meant to ask as the grinding when you put it back in park lead me to believe that you didn't have the complete driveline installed which was why I made the 'both drivelines' comment towards the end of my post and is what Max_Power was alluding to with his '4 wheels on the ground' comment as well. Knowing now that you didn't have the front driveshaft installed, it makes perfect sense given the operation of the BW4472 transfer case. Hopefully the limited amount of running without the front driveshaft didn't smoke the viscous coupling...