95 blazer (ughh) Transmission.... Throw me a bone here
 

Ive spent weeks trying to figure this out. It's driven me to alcoholism. I have even found the end of the Internet searching for answers. So this is my last try to get info. Im getting a new tranny if this doesn't help.

So.... About 2 weeks ago I was driving on the interstate dropping my daughter off at her mom's (shes a biotch). A couple miles before her exit, I notice my tranny wouldnt shift into overdrive. So I get off (haha) and go another mile to the gas station, and the tranny is stuck in 3rd (4 speed tranny with overdrive) so I park, pop the hood, and check my fluid, it was a tiny bit low. I put a quart in there (oops). It ran fine until I got about a mile before my exit and bam, same shizzle. So.... I go to the parts store and get a tranny gasket, filter and fluid to flush it (figured it wouldnt hurt) and let it sit over night. get up the next day and test drove it. Ran fine! Until it got to operating temperature, then bam, stuck in 3rd gear (it seems). When I come to a stop it wont start moving until it hits about 2500 rpm (like i have a clutch or something). So this goes on for a week and a half. And now, it always does this. It doesnt wait until operating temperature. It sucks. I have no answers and I want to drive my truck. Any info? Ideas? Shot's of Tequila?

My truck is a 95 Jimmy 140,000 miles. 4.3l of course. Any help will be appreciated!

Have you read through this thread yet:
4L60E Information & Common Problems - Compilation

I have read through this plenty of times. Just doesn't fit my symptoms.