I just recently purchased a 2000 Blazer 4x4 4 door, and while driving it 3rd and 4th gear went out. The car will try to shift into third then just act like it is in neutral and start revving. Now, this is where it gets interesting. First i checked the dipstick and the fluid was still bright red and smelled just fine. My second action was just to replace the transmission since i already had a 4l60e (which i knew ran and shifted just fine) and not to my surprise it had the exact same issue. I cant fix this issue no matter what ive tried, there is no check engine light and ive gone through 4 sets of shift solenoids. Im in need of help send me any ideas of how to get this car back to shifting, thank you!

 

Losing 3rd and 4th is often an indication of the 3-4 clutch pack having gone bad. It is not an uncommon problem.

 

I thought the same thing as you, until I put in another working transmission and when I went to drive I had the exact same issue. That’s why I am leaning more towards electrical. The only issue is I know absolutely nothing about the electronics on these vehicles.

 

I lost the 3-4 clutch in 3 new transmissions in my 02 Crewcab. Now on number four . Total miles on truck is over 230K.

Bill

 

Was the replacement transmission was used? How many miles did it have? If it had its fluid drained and refilled with fresh fluid then perhaps the new fluid contributed to the second transmission's 3-4 clutch pack failing. I do not have direct experience with this but I have seen it mentioned many times on this forum.

 

In my case, every one was brand new. The original lasted about 100k before it went bad. Then I was getting 30-40k out of the others. Right now it has about 40k and is still working...

Bill