Okay....so my blazer had no issues transmission wise before prison....was loaded on a tow truck about 30 months ago and after loaded and stored..it was driven home with no major issues noticed...Since parked at house under a cover it has lost a drive shaft??? Now the blazer has ability to go forward..shifts good...but does not have reverse...i have put new drive shaft on,changed Tran fluid and filter...it still won't go in reverse so I removed drive shaft and with it running, put in reverse gear, gave it some gas with high rpm....and checked....it still does not look to be getting any spin movement from either hub side or u shaped connection side where brackets are....anybody got any advise or know what it could possibly be...I did check the linkage and it seems to be changing gears from park to low gear alright...ThankYou....

 

Check out videos on line that discuss typical failure mechanisms for the 4L60E transmission. That might get you pointed in the right direction.

 

If you drop it into 1st gear do you have movement, same test for 2nd and 3rd. If you have no reverse, and no 2nd gear then you have a busted sun shell in the transmission. Mine went out a few weeks ago.

 

I'm having the same issue with my transmission. I have all gears except reverse. I feel reverse engage and the rpms move but it just won't move.

 

See this:

https://transmissionfactory.com/blog...roubleshooting