So I just bought an 85 s10 blazer and It's got the 4wd on the floor, not push button. Anyway I've heard that you're supposed to put it in 4wd and put it in reverse for about 10 feet for it to engage. Is this true? And if I don't will is screw anything up?

 

Well, I have the original manual from a '92. It says just shift into 4x4 and go. lol Although, on a side note, I've heard that to get out of 4x4, it may be necessary to go into reverse for a few feet (though I've never had an issue with it shifting out of 4x4).
Does your blazer have an issue with shifting in/out of 4x4? But being in reverse in 4x4 will not do any damage, even if you're trying to shift out of 4x4 there should not be any chance of damage (unless your blazer has separate issues).

 

I've never had any issues with it not shifting in and out so I think it's good to go haha.

 

yeah you need to move a hair to make sure the front end engages. so basically if you drive into a ditch and get stuck and go to put it 4wd it may not engage due to it having to move a hair. ive even had my old trucks with locking hubs give me issues like that. but the backing up to disengage is popular cause you have to take off the forward tension for the front axle to release.

 

on my old 87 i never had to back up to disengage the 4wd

 

Yours can be shifted into 4Hi at any speed.

The reverse to disengage is for the big K5 Blazers with auto locking hubs and solid axle.