The 904 trans in my 69 Dart has been shifting strangely. It:
A) does not shift out of third until the car has almost come to a complete stop.
B) Does not down shift out of third when the accelerator pedal is depressed fully (i.e. merging onto highway)
C) From a stop, under normal acceleration, the shifts form first-second-third are very quick. The car is in third gear by 20-25 mph. When leaving a stop under heavy acceleration the car will stay in each gear longer and shift harder (as it should).
D) Under normal acceleration, the shift from first to second is definite, but, the shift from second to third feels like slipping.

Any ideas of what may be worn out or out of adjustment?

Also, there is an intermittent vibration at highway speeds, like a resonance. But, when the car is shifted to neutral the vibration goes away. Occasionally when the car is shifted back into drive the vibration is reduced, but, it usually comes back.

Puzzled!!

My first guess is a mal-adjusted Kickdown linkage. But, you could have multiple problems going on there. Search the old message threads for proper adjustment procedure.

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'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

I agree that the kickdown linkage may be mis adjusted, does the lever go all the way back at full throttle?

One other thing to do is change the fluid and filter, that may help.
If the trans is in good working order, the next step is to run some pressure checks as outlined in the factory service manual. You screw a pressure gauge into various pressure check points and take the reading at certian RPM, this can really help isolate the problem area.

Fast shifting can be the result of low pressure on the govenor/ kickdown side or high pressure on the main line pressure side of the system.
DD

I had a friend sit in the car and hold the accelerator to the floor while I adjusted the kick-down. The car shifts much better and I am seeing an increase in fuel economy. But, after the tranny warms up, the 2nd-3rd shift is still a bit spongy.
I am still experiencing significant vibration at highway speeds that go away when the trans is shifted into neutral.
Maybe during the Holiday I will have a mechanic buddy of mine rebuild it.

Thanks

OK, the vibrations sound like a driveshaft problem.
The TorqueFlite's 1-2 shift is always pretty good if the throttle pressure is adjusted properly, but the 2-3 shift will seem lazy by comparison. Some of that is just the nature of the (stock) beast, but it can also mean it's time for a rebuild. I'd say, first, change the fluid and filter, & clean out the trans pan while you're in the vic.
While your buddy is flooring the pedal, use a flashlight and look down the carb to make sure you're getting WOT at the throttle blade(s).

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'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

Could be two things: drive shaft U joints or alternator bushing. To test, bring the engine speed up to the same RPM where the vibration occurs with the trans in neutral. If you can duplicate the vibration, then disconnect the alternator belt and try again. If it goes away, replace the alternator. If it is not there when revving at idle then check the drive shaft.

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Chuck Rivers, Webmaster

take it to a trustworthy tranny shop and have'em service the trans and adjust the bands. Should help...maybe the band in 3rd isn't releasing properly. good luck

-Don

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Forget the flowmasters...here come the good ol' GLASSPACKS!!!