If your grinding in park i'd almost bet you just bumped your t-case into nuetral and will be rolling soon!

 

ok, follow up question on the transfer case possibly in neutral. since this is awd, there is no lever. there is an electronic coupling. how do i know if it is in neutral, and how would i engage it?

 

First things first make sure the encoder motor and all speed sensors are plugged in from the t-case. It would help to know which t-case you have (136/246/263 etc) so I can figure out if it is a single speed or 2 speed. Honestly probably the easiest way for you to know is to put it in gear and if when you put it back in park it grinds t-case is in nuetral. If you have t-case controls on the dash try cycling them.(sorry, i havent memorized every possible setup as I work on all makes....but I know some GMs dont even have dash controls on the AWD models) Todd

 

i got a line sheet from the dealer, but all it tells me is it an awd trasfer case NP3. there is no switch on the dash. on this outfit, you don't know if it is engaged or not, no lights, no switch, no lever. I liked the older vehicles ; when you put it in 4wd yourself, then you knew what was going on. i will check with dealer and see if they can translate the np 3 into a number more like what you suggested.

 

I never heard of an awd blazer

was this the tcase removed from the truck ?

 

reading about this in other forums, i realize that this must be a single speed transfer case.. i have no high/low switch, lever or indicator. i have checked the fuses, and am now checking vacuum lines. the only one i know for sure is on connects the transmission and transfer case. from other forums it is hard to tell if this vehicle had another line to an acuator someplace.

 

you did not answer my question tho .. is that the original transfer case from the truck?

never heard of any blazer being awd unless its bravadiva (bravada)

 

The answer to your question was already written prior to you asking it. He stated he had the NP3 option. Check what that is and you'll have the answer to your question.

There were AWD Blazer's through the years that used the Borg Warner 4472 (BW1372) transfer case which was the same as what the AWD Astro/Safari, 1st gen Bravada, and even the Typhoon/Syclone used. There are no electronic nannies in this transfer case. It used a viscous coupling that provides a dedicated 30/70 torque split front/rear respectively. Given this, both drivelines must be installed to get power to the ground.

Best to not get mouthy with someone when you don't know enough about the subject matter to support yourself.

 

we haven't had this since it was new, but from the line sheet, it appears that everything, trans and t case is stock. and yes, this is an awd unit, no switch, no lever, no lights.

 

Well, if you have the 4472 T-case with the viscous and the planet in front of it , or the 136 like Bravada there isn't a way for it to be in nuetral I think. Even if the viscous is bad it will move as long as all 4 tires are planted on the ground. If you really have a pronounced grinding or ratcheting sound when you go back to park keep looking at the case, Otherwise I think I'd be back to the pump being damaged possibly, and would try to rig something as a line pressure gauge.