vette95

My auto transmission is acting a bit wierd. 1st and 2nd works fine but when shifting to 3rd itīs just like itīs in neutral,the engine revs up but nothing happends. There is no burnt smell from the oil and I changed oil and filter today but still the same. It worked fine one day and the next it started to acting like this so Iīm thinking if it could be some electronic valve or something? Any suggestions what this could be? Thankīs.

redvtt

It'll probably need to be rebuilt. My truck (same basic trans, same symptom) did exactly that & I had to replace it. If you do a google search on the transmission model number & the symptom, you'll see what I'm talking about.

vette95

So it wonīt last more than 47000 miles then?

redvtt

From what you posted, my experience was like yours exactly. I looked for a long time for a fix, I reduced the possiblities down to a replacement.
Another common thing is the computer controls the shifting electronically thru electrical solenoids. You may have a defective solenoid, but I'm just shotgunning the symptom. If you have a GM manual, it can step you thru a procedure to isolate the failure (hopefully 3&4 gear solenoid).
Caution: If you drive it longer than 10 miles in it's present condition, it's fried & will absolutely require a rebuild.

vette95

Can I reach the solenoids from underneath if I remove the oilpan? Is there some way to check them so they work as they should?