Our 76 F250 (only 40k miles) has a 460 with C6 trans (I'm told). When I bought it for $82 US a year ago, the old owner said: "sometimes you have to let the trans warm up". Drove it over the winter with no trouble but yesterday, started the truck, put it into Drive and started moving normally. Shifted to 2nd and instantly there was nothing - as if I had shifted into Neutral. Flipped the shifter back to Reverse and she was fine in reverse but nothing in Drive. Flipped back and forth a few more times and suddenly it went into gear. From then on the trans behaved normally. It is likely the fluid is ancient and needs changing but could that and a clogged filter cause the transmission to not shift into gear? I will change the fluid soon (was told it holds a huge amount of fluid) but are there any other ideas out there that I could check and that don't cost too much? Also, when I open the trans will I see little metal filings like in an old manual trans? One final point - there is rust on the shaft of the dip-stick due to being parked most of its life in a driveway in our very damp climate. Sorry for my complete ignorance but this is the first auto trans vehicle I've ever had. Thanks for any thoughts and advice.

 

A C6 that old could have hardened seals or you could be a little low on fluid. Both problems seem to go away when the transmission is warmed up. A C6 normally holds about 12 qts unless its a 4x4 with the deep pan then 13qts. Be sure to drain the torque converter. The filter in a C6 is only a wire screen, unless there is a lot of metal in it you can wash it clean. Some fine material in the bottom of the pan is normal but any actual chunks indicate a failure somewhere.

 

Thanks 'rclarke'... Wow, 3 gallons of ATF - I'd better price the stuff out today. I have a Haynes Manual and will look up how to drain the torque converter. Appreciate your advice, thanks again.