Blazer wont go in any gear, its like its in nutrul

transfer case seals blown
even axle seals or gearbox seals
wont know till you look underneath

transfer case may be ok if not run without oil

Well Sure it is. Disconnect the plug, remove the actuator, use a pair of pliers/ screwdriver and place it any gear you wont. But this is always getting under the truck to swap gears.

Actuator on transfer ? There are also vacuum lines that activate actuators on the axles

it could possibly be the transfer case control module they had some problems with them

the 4wd module is bad and the chain sounds stretched in transfer case there may be a leak

The transmission doesn't have a dipstick but it does have a fill level plug located at the rear of the extension housing, just to the passengers side. It is a round plug with a 3/8 square hole in it.
Fill trans till oil overflows out of this hole.
Use VMX80 or similar.

yea its not shifting again like before ? sounds like your transfer case solonoid has possably gone bad again .. these are a sometimes dont work item .. It is what shifts the transfer case into gear and it might be a little worn or weathered and not letting the switch kick it in gear all the way from the N position. thanks Jerry holler if you need more.

Check out Edmonds.com for Recalls, Service Bulletins ans Complaints. On this Year Model Blazer. You will be Shocked!!!! Luckily I found a Buyer for Ours before it got WORSE!

sensor faulty on transfer case will not light up

first the flashing light means that it is trying to go into 4wd. as far as i know there is no adjustment. The shift motor may be bad, If the transfer case is shifting it could be the silinod in the front differantal.