Going up my steep driveway in the 99 ZR2 Blazer every gear will pull the truck up except 2nd. When I let my foot off the brake, it doesn't roll back when in 2nd. But every other gear will pull and roll back. But it does fine in Overdrive. What gives?!

 

"every gear will pull the truck up except 2nd"

Does the vehicle move forward if you push the gas pedal farther down? Keep in mind you are starting out in a higher gear so you'll have to push harder on the gas.

At a stop, when you select any forward gear except "2", the transmission starts out in first gear. When you select "2", it overrides the default of first gear, and it starts out in second gear. What you're experiencing is normal.

 

Why, would you be trying to pull up a hill in second gear in the first place. Either let it do it's thing automatically or use the gears in the proper order or it wont work correctly for very long.
Unless you have a full manual valve body you can not select any gear you want and it work correctly. You must use them in the proper sequence.

 

Starting out in second gear gives you better traction climbing hills on snow, ice, getting un-stuck, etc. Less torque to the wheels so they don't break loose as easily. That's why they give you the option. Been that way for YEARS on auto transmissions, the owners manual explains it.

 

Say it ain't so.....

 

It moves forward in all manual selections (uphill) except for 2nd. I tried giving it more gas and nothing happened.

 

My rear brakes started grinding metal to metal with no warning, so to avoid compounding the problem, I was manually downshifting for an engine brake effect just to get me home so I could fix the brakes.