does anyone know if the kickdown linkage stays engaged on these trans if they burn up the trans..... i was getting 24 on the highway and then i got into the throttle one day now im getting 6 to 8 mpg on the highway.... the kickdown linkage broke...... my buddy and i are bout to rebuild it but i want to know..... thanks for checking this out!!
I drove my 67 Galaxie with a 390/C-6 for 2 years without a kickdown cable. It didn't burn up while I had it and the kid I traded it with still drives it, just shifts thru the 3 gears like i did. I did hear that you can burn the bands up driving like that though. Good luck! Chuck
The kick-down linkage works in conjunction with the modulator pressure to moderate the throttle pressure valve that over-rides the governor below a certain governor pressure. Basically what that means is that if you run around in drive with the linkage off your line pressure is very low and clutches and bands can slip and shifts are softer. If you shift manually then as long as it is not in Drive your line pressure is held high so no problems, until you put it back into Drive. Manually downshifting from Drive to 2nd the transmission begins to shift and then holds "part way" while the line pressure goes up to engage 2nd gear causing wear. On top of the shifting problems you have one other important consideration. The vacuum modulator has done all it can to increase line pressure when your manifold vacuum goes from cruise of 20 to a load at 10 inches of Hg. This is about the point where the kick-down linkage begins to stroke the valve that raises the line pressure further. If it is not connected then anytime you press down on the throttle and the vacuum drops below 10 inches of Hg you should be raising the line pressure and you are not. There is not enough line pressure to compensate for the additional load on the transmission. The most common result of running without the kick-down lever connected is burnt direct clutches. It takes time depending on the loads and frequency of loads but it almost always happens. Paul
The Jalopy Journal
