I need some advice, as the C6 in my 74 F100 might be dead. Here's the sequence of events leading up to this evening:

1. I bought the truck back last Summer. Didn't get it running till early February. The transmssion had an issue with the 2-3 shift, when warmed up. (When cold, it shifted fine). When going from 2-3, and under normal throttle, the motor would rev and transmission wouldn't shift right. If I would lay off the throttle, it would shift. Sometimes, if I would manual shift, that would help a little.

2. Two weeks ago, noticed that when I put transmission in reverse, it would jump and jerk, almost like the parking pawl was still engaged. Once you gave it some throttle, the reverse would smooth out and truck would go backward. Once, I even noticed that in neutral, the transmission really wasn't in neutral, but in a sort of drive. the linkage is still fine, visually. nothing has slipped in that regard. The reverse issue got a little better gradually.

3. Unrelated I believe, but my carb had idle issues starting yesterday. Believe it is related to some crap in one or both of the mixture ports. I turned in the idle screw so truck would idle smoother. Did this late last night.

4. This morning, after the transmission had warmed up, I heard a sort of faint whining noise, and then, all of a sudden, while in Drive and at about 35 mph, the truck simply acted like it fell out of gear, almost like it was in neutral. This was the case in D, 2, or 1. At first, when I backed off throttle completely, then truck would regain Drive, but not for long. Interestingly, when I would stop, turn truck off and put in Park, then start back up, I could drive for another 2-3 minutes.

This sounds serious, right? Any suggestions about how serious?

 

My first suspicion would be the pump is on it's way out. It's time to rebuild.

 

Fluid is good?

 

Yes. Fluid level is good. It doesn't look burned (brown) though maybe not all red. I changed out a modulator about three months ago so has 3-4 fresh quarts anyway.

 

I guess rebuilding the c6 is the way to go. Sometimes I think a good built c4 behind the 390 would better transfer its power.