I have a 96 chevy blazer ls

I was on the 160 highway going abt 65-70mph
and at first I felt a little shimmy, so I'm like the hell is going on, I took foot off gas then lightly got back on it and she started shaking hard, so I pulled over onto the shoulder. I thought maybe transmission but after a couple minutes I turned her back on and she started up and purred, sounded good(I've done some work on the engine) but N [D] D 2 1o was able to put it in gear, and I'd push the gas and it would Rev but not move, even in neutral. My rear wheels were siezed.
I've never worked on a rear diff, my grandpa said maybe it's a U joint..
so I'm just here asking for any help, tips, whatever so I can crawl under her and maybe it's not a huge deal. Any help would be very grateful

 

It sounds to me it could be your transmission.

The only thing to do is get under it and check the rear axle for proper operation and then remove its cover to inspect for any obvious damage.

As a start on the transmission diagnosis, you might watch this.

 

Block the front tires to prevent the vehicle from rolling forward and backwards.
Jack the rear wheels are off the ground and secure with jack stands.
Put gear into neutral.
Turn the rear wheels by hand. Feel for any binding and listen for any noises that don't sound good.

If it were a U joint there'd be a lot more noise and movement and not just seized completely.

You could also disconnect the driveshaft and turn the rear wheels on the axle by hand to rule out if it's transmission or the rear axle itself.

 

Good advice.

And it should go without saying to block the front tires to prevent forward and back motion.

 

Correcto. I edited my original post.

 

Thank you for all the input.
I haven't had a chance to lift her rear end up, holidays, work etc..
I don't think it's the transmission, she will go into gear.
the battery died while I was on the side of the 160, I've charged the battery and I put it in gear; in reverse, it went about 1/3 of a rotation, then in drive, foot off break a little gas and 1/3 forward.
both times the rotation was stopped with a thud.
so I stopped trying to get her to move.. the abs light is on,, I thought maybe a loose or disconnected sensor at first. I also changed out most of the fuses, idk how long it had been since someone did. They were crusty.
This weekend I'm going to get her up so I can crawl around under there and also try rotating wheels by hand..
so I'll hopefully have some idea and post some pictures.
again, thank you for the help and apologies for the wall of text.✌

 

"If it were a U joint there'd be a lot more noise and movement and not just seized completely."

WRONG. IT HAPPENED TO MY OLD PLYMOUTH FURY.

Ujoint locked so tight it had to be towed

 

That's a rarity. I suppose it can happen.