4L60E rebuild, no 3rd gear

[Nima]

Hi There:
For the first time I rebuilt a 4l60e (2001 suburban 1500 4X4) which had failed 3,4 gears. I watched a lot of videos and I followed transmission bench rebuild videos mainly for the rebuild. I was very confident that I followed the instruction to the point. I replaced the sun gear as well the shift solenoids.
Long story short, I took the the truck for a less than a mile test drive on our private road, I didn't notice if it shifted to the 3rd or no since I was going slow and trying to listen for any explosion! when I got back, I noticed the huge transmission fluid puddle under the truck. The cooler return line has popped out and tranny was drained. There was this slight hot/burning smell. I popped the line back in (double and triple checked it again), filled the tranny again, went through all the gears few times while stationary and took it for another test drive. It does not shift to 3rd. It doesn't even try. Did I burn the 3rd and 4th? Is there anything else I can check? does less than few minutes will ruin the clutches?
Thanks for the help.
I guess I have to add this: there was a lot of fluid leaked on the exhaust pipes and I am hoping the burned smell was from that.