Hey guys. Ive got a '78 F150 4x4, 400/C6. I recently purchased this truck and have no idea of its history. I ran it for a few days and it seemed to run great. Oils were all clean. Trans shifted good. Engine seems strong but was acceleration was a little sluggish. I had just shifted into drive and was moving slow. All of a sudden the engine stalled. It started right back up and then I had what seemed like no trans gears. I checked the oil, it seemed clean, definately not burnt. Tried all t-case gears, that didnt make a difference. Got underneath and I checked all linkages. Trans seemed cool. It has the trans cooler in the rad as well as an aftermarket one in front of the rad. The only thing I found was the kickdown lever was disconnected at the carb. Hooked it back up , still no diff. Towed it home and put it in my shop. Removed both driveshafts. Ran and found output yokes would spin but I could stop them by hand. Forward/Reverse/ and the T-case seems to shift properly. Drained tcase oil - perfectly clean. Dropped pan and screen on tranny. Oil was clean and neither the pan or the screen had a spec of dirt or metal in them. Trans has definately been removed once. I removed the inspection cover the the torque is bright red? Think its factory? I stopped there to think about it for a day. My 2 guesses are either the tabs broke off the torque and the pump isnt working, or I broke the imput shaft? You guys have any ideas before I tear the thing out? Any help would be great. Thanks.

 

Red converter would not indicate a factory converter. You are on the right track though. If the converter was not installed properly it could have broken the pump drive . That is not good. The first thing that came to mind though was that the converter bolts fell off, and it is no longer attatched to the flexplate. It is odd that all of the gears are bad. Is the shift lever / linkage, or the actual shaft in working order? Does it go into park? Maybe it went into neutral, and broke there. That would not explain the engine stalling, but it is worth a look at this point.

 

Thanks for the info. When I saw that red converter it didnt look stock to me. I did check all the shift linkages. When It happened I jumped out and that was the first thing I thought of. I thought something broke inside of the column. Everything seems to work good tho. I cant say for sure if park worked or not. I didnt get a chance to work on it tonite but i will check tommorow. I also thought about the converter bolts but they were in place. I wish it was something that easy. I guess the next thing will be to turn the engine by hand and look up inside the trans, passed the valve body, and see if I can see anything moving. I was also thinking today that I should check my crankshaft endplay. If I dont have any that might be an indication of that torque popped out of those drive tangs. I'm not as upset at this happening as I am anxious to see what actually happened. Seems like a bit of a mystery.

 

Converters require a special FoMoCo locking nut. If someone just installed regular nuts, the results could be what the member above referenced to. A red converter is something a tranny shop would do. Some shops paint the converters red, some green, some blue, it's done to ID the converters as to who rebuilt them. Something else to consider. If the engine has been in/out recently, it's possible the transmission was not lined up on the 2 dowel pins. If not on the pins, that will cause the center section of the flex plate to separate. Also check the transmission manual control lever...where the linkage from the column attaches. there actually two levers, one inside the other. The outer lever may have a plastic bushing. The lever where the trans rod attaches at the bottom of the steering column also has a bushing, it could have broken, it snaps in...check that too.


378941-S .. Converter Locking Nut

 

Turning the engine by hand and looking up into the transmission will tell you nothing.
The pump must be turned greater than idle speed to get anything to move inside the transmission.
Automatic transmissions use oil pressure to apply the clutch packs.
If the pan is off there is no fluid for the pump to make any pressure.
An easy test is to disconnect a cooler line at the rad and fire the engine up.
If fluid pours out under pressure the pump is good. I have seen the input splines in the convertor spin out cauasing the same affect.
The convertor has 2 flat areas that coincide with 2 flat areas in the drive pump gear.There are no real "tangs" on a C6.

 

There is a pressure tap on the side of the case, I believe it just forward of the band adjustment, or maybe just behind it, I don't totaly remember. install your pressure guage and see if you have any pressure while its running.