I have a 1997 GMC Savanna 2500 5.7L.
My Transmission doesnt shift from first gear. Top speed is 15MPH.
It goes up to 15MPH while I'm driving around the block after car doesnt move forward anymore. After about 5-7 minutes after shutting down the car it would move for a while then the same thing happen.
Also I dont know if this help but if I start it up and let it warm up it would move only out of my driveway.

 

the first thing i would try would be a tranny flush with a new filter and see what that does for u.

 

That whats I'm thinking. But would an ATF fluid really solve this big issue.

 

it might its the cheapest thing to try first. pull the dip stick and smell it you should be able to see if the fluid is bright pink or black and burned smelling. then go from there. my buddys car wouldent even drive over a speed bump untill we changed the fluid.

 

OK thank for the thought.

 

no problem. post again and let me know what u find out.

 

Well your right, I change the fluid and filter and it ran fine. No hard shifting. Thank for the help and saving my time.

 

no prob. glad i could help.

 

Well now the trans fluid is brown. I think I need to chain the fluid in the torque converter. How do I do It

 

i think by changing the fluid a few time with cheap fluid then puting the good stuff in should do it. to change the fluid in the converter would require taking out the tranny. once your done it should be brite red and stay that color. and i forgot drive it a bit between each change to run the fluid though it good.