W Vin.

Replaced lower intake manifold gasket, still got a few random vacuum lines to hook up, but I drove it to work and the trans barely shifted. It would go up yo 3-4k rpm and would shift only when I let off the gas.

Is there a vacuum line that needs to be connected in order for the transmisson to work?

And about the tstat, I replaced it while I was in there, last time I put one in it seemed loose and the truck never got up to temp. This time the guy at the parts store told me I needed this little rubber ring that fits onto the tstat, and that I wouldnt need a gasket, so I put the rubber ring on, and put permatex waterpump/thermastat sealant on the flanges and its leakign of course, the box didnt even say the rubber ring was for my blazer, do I need it?

 

Not sure about the transmission. My Chevelle has a th 350, and it has a vacuum modulator that needs of be present for proper shifting. But I don't think the 4L60E has that. It doesn't even have a tv cable like the 700r4s do. But if you still have vacuum lines unhooked, you probably have a vacuum leak, which isn't going to help your engine run right, and might mess with shifting.

When I did my thermostat, I didn't use any weird rubber ring. Just a new t-state and new gasket. Sounds like you might have gotten the wrong thermostat.

 

I had all the lines plugged.

Just hooked them all up, besides the one on the pass side of the upper intake manifold, no idea where that one goes.

Same issue, took it down the road, from 1st to 2nd gear it rev'd up for like 2 seconds then shifted.

Dont know what to do from here. I got 2 4l60e's in my garage, but thats a last resort, one is out of an 96 trans am lt1 which from what I told would bolt right now, the other is from an 01 camaro LS1.

 

Take a look at this link. Number 16 in the list might help you...or one of the others in the list. https://blazerforum.com/forum/tech-a...ilation-37689/

 

On the thermostat... the rubber ring around the thermostat flange IS the gasket. The Permatex is what's causing it to leak. No gasket or sealer of any type should be used, just the rubber ring.