Hi I joined this forum hoping that someone out there would have some idea what is going on with my 2000 blazer. I had to replace the transmission about 2 weeks ago. Put another one in and the truck ran absolutely perfect...until today. Today I was backing my small trailer into my brothers yard, we had snow here today so I put it into 4lo and went to back up it felt like I hit something, and the front tires werent spinning.
I put it in automatic 4x4 and it went. Afterwards when I was leaving the
truck only goes a few minutes and then seems like it is in neutral it revs up but goes nowhere. I have to shut it off and wait a minute or two and then start it up again and it will go so far and then do the same thing. It did it 5 times in the 2 mile ride home. I looked online read about limp home mode and checked and if I put it in 2nd gear it goes but what I read says if it is limp home mode you can only go in second gear (which I can)
but you should have reverse (which I dont) Now when I shut it off and wait and restart it, it all shifts fine and I have reverse then when it seems to go into neutral and wont go unless it is in second gear I lose reverse but when I wait and restart it it all comes back shortly. anyone have any idea?

 

Is the Service Engine Soon light on? If so, what DTC's, (Diagnostic Trouble Code) are in memory? Autozone, Advance auto parts & O'Reilly will retrieve them for free. Write them down in the order they are retrieved and post them here.

 

This thread lists some of the common symptoms and troubleshooting:

https://blazerforum.com/forum/tech-a...ilation-37689/

Lack of 3rd and 4th gears is worn out "3-4" clutch. Seems odd that would be happening, though, if you just replaced the tranny. My 3-4 clutch went out at >200k miles.