I recently purchases an 82 GMC Sierra. When I bought it, it didn't have an air cleaner, so I bought one and installed it. The next time I drove it, the rpms continuously went higher and higher. It seems the new air cleaner was binding the throttle cable, holding it open. Apparently, you can't just turn off the key on these trucks without it being in park (it's an auto). I am out in the middle of the road, so when I go to put it in park, I hear the distinct CLUNK CLANG. I shut off the truck and get out to remove the air cleaner. When I start it back up, the throttle problem is fixed, but it won't go back into gear and there is tranny fluid all over the road (but I would say it's a quart or less, if the amount even matters). I push it back into the driveway, and it can still go into reverse, but it doesn't seem like anything else works. Long story short, what is the best case scenario here? I am going to put a quart of ATF back in and see if (where) it leaks out. Is there any possibility it's the shifter or something I can get to on the outside? Or should I just cut my losses and hit the junkyard now? Seems doubtful there is a cheap solution to this, but I am no expert. Thanks in advance for any advice.

Welcome to AF, if the trans is full and you are sure the shifter is in dr or even low and no forward, the trans is done, off to the yard.