so yeah today i was coming home from work, and about halfway home, my car starts trippin. It's seems to take forever to shift gears, it's an automatic, but i don't really know what kind of transmission it is.... took it out for a trip around the block and sometimes it doesn't even shift..... and ideas?

 

sounds to me like the vacuum line came off the modulator valve or the modulator has went out.check the vacuum line at the intake and the modulator

 

thanks. My dad checked it out yesterday but was only able to check one end of the line... he said we need to lift the car to check the one under the car..... if it is the modulator, how much would it be to fix/replaced? What if it's none of those?

 

a modulator cant cost a whole lot,i havent had to buy one.is it slippin when its trippin or is it just not shifting right.you can adjust the modulator with a very small screwdriver,take the vacuum line off and insert the screwdriver and turn clockwise to increase the shifting point or counter-clockwise to decrease the shift point.if it just started doing this for no reason at all ,i would check the vacuum lines ,if that dont work i would change the modulator and adjust if needed

 

we'll my pops went out of town so i guess i'll have to wait til gets back to check it out, no cruising around til he gets back....

 

You can buy an adjustable modulator for a TH350/TH400 from Summit for 15 bucks if I remember correctly.

I just saw your post about the cam. Changing the cam can change vacuum pressure if it's a big cam. If you're running power brakes it can affect those too. Changing the carb from a vacuum secondary to a mechanical secondary can also affect the way an automatic transmission tells if it's under load also from what I understand. I'm not sure HOW MUCH that will affect shifting as I don't know transmissions too well.

 

so does that mean the vaccum line might have just come off? if it did just come off, should i just change the vaccum line or just really make sure the current one stays on?

 

I know this sounds stupid but where is the modulator located

 

The Modulator is on the side of the trans,pass side. If your trans is clean it is probably gold and should have a metal vacc line going to it. It wil be connected with a short piece of rubber hose.

 

Thank You SOOOO Much I will look and see. Hopefully this will fix it.