Transmission Question

[suki243]

Lately I've been having some problems with the transmission. The most obvious was some pretty hard shifting.

This set of hard shifting tends to occur after i finish my initial trip, say from school to home, park in driveway with the engine still running then leave. When it shifts from 1st to 2nd sometimes its fine but other times it lets the rpm go really high then it jerks and then continues into 2nd and it seems like it stays in 2nd until i let off the gas, then as i'm coming to a stop rpm's go down and the shift into 1st also is a huge jerk and then it continues.
When this happens and i'm idling it feels like the car is being pulled back and has to overcome to the transmission to roll. For example if i pop it into neutral it rolls perfectly but if its in drive you can feel it fighting it.

My transmission leaks so i thought it may have been low fluid causing this, so i checked the fluid and it looked on the lower side, added about 1/2 a quart and it seemed to have gotten worse. Any ideas? (btw it is an automatic transmission, 1966 coupe, not sure if its the original c4 the previous owner says it is, but the first drive gear slot on the shifter is normal drive, the 2nd slot is 1st gear only and the 3rd slot is a lower gear)

Suki

 

[shoguun]

i completely guessing but maybe your automatic kickdown but thats a guess and i may be just way off.

 

[woodsnake]

I'm thinking a bad vacuum hose in the modulator area. You'll have toget under the car and check to see if it has come off. There should also be a short bit of rubber hose that goes from the intake manifold into a steel line that goes to the modulator valve.
I'd start there...

 

[robbz28]

My car was behaving similarly, very erratic in the shifting, sometimes fine, then other times it would rev high, I had to get a new modulator, but that fixed it right up, Auto-zone had one for 12 bucks, now it works great