don't shift right

today i finally snowed up here, so it's hard to take off at stop signs.
So i put my blazer in to four wheel drive, waited couple seconds to make
sure it went in, and then i took off from the stop sign. I thought it went into four wheel but my back tires strated to spin and then i hard a clunck which mush have been four wheel popping into place. I start going down the high and switch back into 2 wheel. as i'm gaining speed my car shifts, and when it shift again nothing grabbed, it felt like my car was in neutral instead of overdrive. So i was thinking if anyone had this problem before and know what's going on.
I have a 1997 chevy blazer. 4 door.

Don't shift out of 4wd while accelerating!

it's shifts out of 4 wheel drive. I should have explained alittle better. When i drive down the road as soon as i hit about 35 - 40 mph the tranny slips and it's like i have it in neutral. I doesn't go anywhere, it'll just rev up high. the 3rd gear has the same problem as overdrive.Every other gear is fine. I checked the tranny fluid and it was bone dry, so i filled it up to where it's supppose to be. i was going to get my tranny filter changed and see if that works. I want to see if anyone knows anything before i end up wasting money on something that won't work

If your transmission dipstick read nothing, you may have found your problem. My next questions are.... Where did it all go? What is the frequency that you check it?

I was wondering where it went myself. Last month i had checked it out. I just purchased the vechicle two months ago. So every month i check fluids to make sure i have enough. When this problem happened yesterday, my sisters boyfriend took a look at the fluid level and it was bone dry. Refilled it and it still is not working right. I'm being told by a couple friends to get my tranny flushed and they say it should stop the leak and fix the problem. i do have 109000 miles on it too.

Check you transfer case for being overfilled.

The seal between the two will leak and the fluid from the transmission will migrate there over time.

Also, did you check the transmission fluid with the engine running in park?

I checked the tranny fluid in park, i added some to it and still don't work, so i'm just going to get a different tranny put in it. I was told that i could use a tranny from 1993 and up. Also i was told that a full size 4.3L would work too. Is there and more make, model or years that i could possibly take a tranny out. I do have an older blazer at my parents house that is just sitting there. I'll have a mechanic check out my transfer case for me.

Was the truck running when you checked the fluid?

Just making sure because the truck has to be running to get an accurate measurement on the stick.

does anyone know what other transmission can fight into my 97 blazer, it's a 4.3L s-10, 4x4. Any other year or different make that can fit in there

96 to current will work fine.