Transmission modulator
Mountain Pass
Joined: Jun 2004
Posts: 241
Likes: 0
From: Canada
It is used to supply a engine load signal to the valve body. The valve body uses modulator pressure and governor pressure to control shifting. This is how upshifts are delayed with greater amounts of throttle applied. Late upshifts are often caused by bad modulators. However in many cases the problem is the vaccum hose has fallen off or has been put in the wrong spot. Any fluid present in the hose at the modulator means it is bad....Don
New User
Joined: Jan 2005
Posts: 2
Likes: 0
my 81 f-250 4x4 slips sooo bad even after an ungodly amount spent on a rebuilt trainy,is it possible my incomp, mechs overlooked a bad modulator?they actually apparently broke off the starter bolt in the bell housing somehow!
Elder User
Joined: Oct 2004
Posts: 541
Likes: 0
From: Fleming Ga
Sounds like they may have cut a seal when putting back together (If they changed the seals, Have ran across some suposedly overhauls where they just changed the clutched and not the seal).
Could have a bad front pump although rare.
Could have a weak pressure regulator spring or sticking valve in the valve body.
If the problem is in secong gear, could have a badly adjusted band.
Could have a bad front pump although rare.
Could have a weak pressure regulator spring or sticking valve in the valve body.
If the problem is in secong gear, could have a badly adjusted band.
