I posted this in the Older Fseries forum but Ima put it in here too in case someone has an idea.

So I was driving my truck today with no issues and all of a sudden, as I pulled up to a red light, I heard a clunk, and forward gear stopped working, like it slipped into neutral. I put it in park and reverse, both shifted fine, and reverse worked fine. But D, 2, and 1 gave me nothing. After getting it towed home (fun...) I checked and the linkage is working fine, moving though all the gears. And I checked the tranny fluid, still red, at the hash marks and no burnt smell. It clunks into reverse and neutral, but not D, but you can hear a load on the motor change from out of neutral.

For grits and shiggles I put the TC in 4 low and was able to move forward, but only at idle speed, giving it gas didn't really do anything other than make the revs go up. And that was with the front hubs unlocked so power was still going to the rear wheels.

From what I can tell, nothing has come loose from the outside, and i didnt see any electronic connectors loose or anything.

I am guessing somthing might have gone bad in the TC. I am thinking of taking it over to a tranny shop unless anyone has any suggestions.

88 F250 extra cab
351w
I think its a C6 tranny and I am not sure of the TC.

Any help would be great.

-Ryan

 

It can't be the transfer case (TC) if it still moves in reverse. It also can't be the torque converter (TC) if it still moves in reverse. Something mechanical has broken inside the transmission.