99, 3.1L, Won't shift to 2nd gear when cold

Lumina 99, 3.1L. When the car sits overnight and is first driven in the morning the first gear gets "stuck". It won't shift to the 2nd gear even if the rpms go high. When I lift my foot off the gas pedal it will shift to higher gear after a while. It does this a couple of times at first when I stop and go. Then it starts shifting normally.

I am not sure if this model has a modulator that does the shifting...

Does any one have experience with the same problem?

Could this be a modulator problem??

Thanks!

That's how a modulator behaves when the it has a small leak (like a hardened vacuum supply hose) that gets better as it warms up. But then again, pressure seals behave likewise when the sealing surface is scratched. That's why the had that problem with all those rack and pinion units around 1990 that wouldn't work right the first couple of turns in the morning.

If you have a modulator, that'd be the first thing to check, but I thought they did away with them by your year. I could be wrong.

There was another post about this, Richtazz suggested a faulty 1-2 upshift solenoid. He knows better than me...

That's how a modulator behaves when the it has a small leak (like a hardened vacuum supply hose) that gets better as it warms up. But then again, pressure seals behave likewise when the sealing surface is scratched. That's why the had that problem with all those rack and pinion units around 1990 that wouldn't work right the first couple of turns in the morning.

If you have a modulator, that'd be the first thing to check, but I thought they did away with them by your year. I could be wrong.


DO you know how the modulator works? I was looking at the car and it looks like this model still has the modulator.

I am mainly wondering that is there any easy way to test it?

Thanks again!

Pull the vacuum line off at the modulator end, if fluid comes out, it's bad. Make sure the rubber ends are good on both ends of the steel line.