1st and 2nd work, Drive, not so much

[masenj]

I currently drive a 91 Ford Festiva and it's ran great for the past 2 years. But today my transmission started acting strange.
When I put it in drive I cant get out of 1st, but manually using the 1st and 2nd gears on the gear shift works fine.
I already checked the transmission fluid, it was low but even after filling it the problem remained.
Does anyone have any advice on this?

[crazyrog17]

Are you checking the fluid level when the transmission is at operating temperature with the engine running?

[masenj]

Yes, at temperature in idle it was low, I filled it until full but the problem remains

[bhazard]

Bad vacuum modulator maybe? At least make sure the vacuum hose going to the trans is okay.

[masenj]

I'll give it a look, ill post my findings tomorrow. For now I need some sleep

[Movin]

If the modulator hose looks good remove it from the modulator and make sure no transmission fluid comes out of the hose. New modulators are adjustable to control kickdown RPM. When kickdown is normal upshift should be fine. The adjustment is a tiny hex inside the nipple and adjusts spring tension in the valve. Other things can cause the same symptoms but are not common.

Just think, the big city tranny shop would be selling you the whole rebuild!!