anyone ever heard of a tranny/converter destroying thrust on crank?
01-23-2006, 09:02 PM
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anyone ever heard of a tranny/converter destroying thrust on crank? Have you???? Any ideas on how it might happen and how to avoid it if putting the transmission back onto a different more expensive motor????
I've been told it could be from excessive line pressure in the converter or a kinked line going to the transmission cooler.... Or a stuck pressure switch inside the tranny..... Either way it basically destroyed my 8000 dollar 355 and don't want it to take out my twice as expensive 383.....
I've been told it could be from excessive line pressure in the converter or a kinked line going to the transmission cooler.... Or a stuck pressure switch inside the tranny..... Either way it basically destroyed my 8000 dollar 355 and don't want it to take out my twice as expensive 383.....
01-24-2006, 10:11 AM
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So how do i fix it????? What controls line pressure and why would my TH400 that was brand new destroy my motor after 3000 miles????
What controls the line pressure???
What controls the line pressure???
01-24-2006, 10:29 AM
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Another possibility is that the converter "sticks out" too far
and is full time interfering, pushing the crank back into the
motor. If this is a deal where you had to cobble up a LS1
flexplate, spacer/adaptor, old-style TH400 converter maybe
the tolerances just stacked up the wrong way? If you have
the converter bolts loose, the trans still bolted to the motor
and you can't spin the converter, it's in that kind of a bind.
On the 400 I expect the line pressure is vacuum modulated,
maybe against a higher than stock head pressure (mechanical
reg). At least this is how I'd bet, if it's a performance unit.
At 300PSI I reckon you're talking 300-400lb of thrust load.
Seems to me the thrust bearing oil film ought to be able to
buck that, but maybe it's a marginal situation? What kind
of line pressure would push through the film and make it go
metal-metal? Anyone know the working limit?
and is full time interfering, pushing the crank back into the
motor. If this is a deal where you had to cobble up a LS1
flexplate, spacer/adaptor, old-style TH400 converter maybe
the tolerances just stacked up the wrong way? If you have
the converter bolts loose, the trans still bolted to the motor
and you can't spin the converter, it's in that kind of a bind.
On the 400 I expect the line pressure is vacuum modulated,
maybe against a higher than stock head pressure (mechanical
reg). At least this is how I'd bet, if it's a performance unit.
At 300PSI I reckon you're talking 300-400lb of thrust load.
Seems to me the thrust bearing oil film ought to be able to
buck that, but maybe it's a marginal situation? What kind
of line pressure would push through the film and make it go
metal-metal? Anyone know the working limit?
01-24-2006, 04:57 PM
#6
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TC has about 0.2" of back/forth travel
(when TC is installed, sits about 1" past bell housing surface;
measuring engine surface to TCC side of flexplate is about 0.8");
if TC is not all the way in, then TC pushes on crank as bell housing bolts are tightened;
so when TC is installed correctly, this problem will not exist.
(when TC is installed, sits about 1" past bell housing surface;
measuring engine surface to TCC side of flexplate is about 0.8");
if TC is not all the way in, then TC pushes on crank as bell housing bolts are tightened;
so when TC is installed correctly, this problem will not exist.
