Playswithcars

Can anyone tell me how much ATF if any comes out of the trans when the modulator valve is removed from the case? Trans is from a 1977.

Thanks,

Bob

C2C3PO

Not much at all. Unless you do it when the tranny is warm/hot or you've slightly overfilled the transmission ( check the dipstick) you might see 1/6 cup maybe at most .
If you're concerned, drive the passenger side of the vehicle up on a block of wood and that slight angle will likely be enough to compensate for any spillage.

doorgunner

Rookie question: Would it be a good thing to install an adjustable modulator valve?

C2C3PO

Depends on what you are trying to accomplish. Are you wanting to adjust the shift points to match a different RPM? That would be the only possible benefit I could see to using one.

Playswithcars

Belated thanks for the info. When I removed the modulator, about 2 1/2 cups of fluid poured out. Since someone previously replaced the dipstick tube and stick, I'm not sure of the full line. It had been reading at the full line when hot. The modulator was pulled when the trans was cold, so I refilled the trans with the amount the spilled out. Do you recommend to pull the modulator again when trans is cold and let the fluid seek it's level?

Thanks, Bob

doorgunner

I can't answer your question.....but I would advise you to scribe a new line on the dipstick once you are sure that you have the correct amount of fluid in the case.

C2C3PO

No I think you're fine since transmission fluid levels do fluctuate quite a bit depending on temp - the 2+ cups you mentioned won't be an issue. Better to have a tad too much than too little.