Th400 slip??
Thread Starter
Instructor
Joined: Feb 2010
Posts: 112
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From: Gillette Wyoming
Th400 slip??
Have a 73 with th400 and 350, I am not to up on automatics, it feels like it is slipping in second and goes right to third under hard load, but if I shift it mannualy to second it is OK does not seam to slip is it the cluches or is it the valve body plugged I am thinking it sat along time before I got it, have run into a lot of things wrong just from sitting along time, I allready changed ther fluid and filter.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Do you know the history of the tranny? Has it been run really hard? Are there a lot of miles on it? Slipping clutches are due to one of two things: abuse and lots of clutch facing stripped off the plates with the plates being burned and warped; normal wear of facing material, but so worn that the clutch piston is actually leaking apply pressure and not engaging fully. Either way, it's probably time for a rebuild.
If the 'history' of the tranny is way different than that, other things are possible causes.
If the 'history' of the tranny is way different than that, other things are possible causes.
Burning Brakes
Joined: May 2008
Posts: 860
Likes: 0
From: Stratford Ontario
It is probably the band slipping. When You drop it into low 1 there is an extra band that grabs so first to second would then feel normal. Then if You leave it in automatic You will feel it slip between first and second.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
It's not impossible that your problem could be in the V/B...but highly unlikely. The shift valves are normally ON or OFF...they really don't regulate pressure, they apply or disapply it. For a clutch to slip because of the valve body, there would have to be a big leak somewhere, even though the valve had moved to "apply" position. It is possible that a valve could stick in a partially open mode...but then it would stay that way and you would get much different symptoms.
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