Th350 modulator
 

So im wondering what would be happening if the line to the modulator on my th350 was just gone? Because its not there its somewhere laying on a road in georgia.
How does it work? And would this have anything to do with my lake size transmission leak?

Re: Th350 modulator
 

modulator does a few things and also controls when the trans shifts along with the govenor .

yes it can be a fluid leak point if the seal inside is bad or the o-ring on the outside to the trans body is bad .

there cheep new so i would prob just drop a new one in .

also the trans dipstick tube design over the years was a point of leaking on the o-ring style . if you have the full rubber grommet seal they hardly ever leak .

the o-ring seal dipstick body design just sucked . best way to seal them is easy .
#1 = drain the trans below the dipstick tube level .
#2 = clean the surfaces 100% of trans fluid and grime with brake parts cleaner.
#3 = good bead of black rtv around the tube body to trans case and let it cure atleast 12 hr's before refill and level check .

Re: Th350 modulator
 

If the vacuum line is missing it would cause the trans not to shift properly, and the engine to run poorly. The leak will be something else.