I have a 2000 Chevy Blazer LT. Recently I was pulling off from a stop and it shifted fine from 1st to 2nd gear, but would not shift into 3rd gear and the check engine light came on. I made to an Advance Auto parts store and read the codes. I was told I had an ABS code, misfire and a slipping transmission code. I forgot to ask what the specific code was. They reset the check engine light. I manually shifted it to 2nd gear because it was very weak when going up hill. I had to drive it 20 miles to get back home going about 30 mph. That sucked, but made it. Check engine light never came back on. I know why I got the ABS code, that's no problem. I hadn't noticed a misfire and never had a problem with 3rd gear. Do I need a rebuild or could it be just a shift solenoid. Don't have much knowledge about transmissions.

 

When you say you would not shift into 3rd, do you mean it stayed in 2nd? This would be opposed to the common failure mechanism of it trying to shift into 3rd but the engine revving instead as it instead shifted into neutral. If the later, then it is likely a bad 3/4 clutch-pack. (That is what happened to me.)

Hopefully Transman will offer his diagnosis. He knows all when it comes to transmissions.

 

 

The 2 who already responded back too you really know their stuff If you end up needing a new Tranny or a rebuild I would check a junk yard or 2 and get a used 1... My local shop wanted $800 bucks too rebuild my 98 Blazer 4x4 but I ended up finding 1 out of a 4x4 S10 pickup with a 30 day warranty for $300 this past summer and it is working just like new and saved a ton of money

 

I had previously did a fluid and filter change because I was slow to move in reverse. It worked fine after that. But when I pulled the pan it did have some dark sediment on the bottom of the pan. After my recent problem, I pulled the pan again and the fluid was dark, but no sediment was present. The fluid level is fine. I drove it again today and decided to push it little more this time, which I didn't do before not knowing what it might do. It revs and then gives a slight jerk before shifting into 3rd gear. Keep in mind this Blazer has 165, 000 miles on it.


​​​​

 

When I first did a fluid and filter change, it had some dark sediment on the bottom of the pan. I did the change because it was slow to move in reverse. I changed the fluid again, this time no sediment. That problem was gone after that. I decided to drive the blazer again and push it a little to see what it would do. It revs, gives a slight jerk and does shift into 3rd gear. I was trying to see if the check engine light would come on again, which it did not. My fluid level is fine. It climbs hills fine now, which it wasn't when my problem first appeared.
​​

 

I decided to drive my blazer to see if the check engine light would come on again. It did not. It now revs a little, gives a slight jerk and then shifts into 3rd gear. I never pushed it when the problem first occurred because I didn't know what could be wrong. Before this problem I did a fluid and filter change, because it was slow to move in reverse. It drove fine after that. The pan had a black sediment on the bottom. I didn't notice any burn smell. After my problem I did a second fluid change to see if it would help. This time there was no sediment., but the fluid was dark. Have no idea what the trouble codes were. The check engine light was reset. Is there a way that code could still be retrieved?

 

Don't know what it is that caused the failure but that you had sediment and the fluid is brown does not sound good. Sediment should not be there. That is was means something disintegrated.

 

If you replaced the Tranny fluid that quickly and it was already dark again christine is totally right, not good... I fear you need either a rebuild if you want to pay a much higher price or grab 1 from a junk yard and save a bunch of money...