Slant 6 Automatic problems

[Alf]

Used the 66 Dart to tow the camper trailer to a show yesterday. Coming home there is a big hill just as I near home. Pulled to slow lane and went up hill in second gear and then the auto would not shift back to top gear. Had to drive the last bit home slowly in second gear. Trans was real hot (it does run a separate cooler)

I let it cool overnight and then went for a drive this morning and it all worked perfectly?

Going to take it in tomorrow to get checked but, anyone got any ideas?

I don't know what the history is of the auto. It is the original box so may never even been serviced in nearly 50 years.

 

[crj1968]

too much heat making your fluid too fluid

 

[grumpuscreature]

Back in '68 dad bought a 19' travel trailer and used our slant powered '67 Valiant to tow it. Even after the tranny cooler installation (2nd trip) we had the same problem you are describing. Before the 3rd trip, the car went into the dealership and the 904 tranny was upgraded to V8 specs (extra clutches and steels in each pack) and a shift kit was added. The 7 1/4" rear was also treated to 3.91 gears and a sure grip. End of problem. After I got my licence in '69 I learned that the Valiant would break the rear tires loose on the 1-2 shift under full throttle...