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Tight Convertor?

1067 Views 8 Replies 6 Participants Last post by  bcfitzsimons
What are some signs of a convertor being too tight? What will the truck do, how will it act when accel? What Would the convertor to stall the truck when going from park to reverse but not stall when going from drive to reverse?
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I intentionally put a tighter converter in my truck when I did the tranny work. It will pull a lot harder because the converter's much more efficient, and you won't have as much "slush" in terms of the fluid coupling beeing too loose. I guess the best way to describe it is that if you're stopped on a steep hill, it will take less engine revs to get the truck rolling-while a looser converter will need more engine revs.

In terms of your question as to whether a super tight converter would stall the truck out-I guess in theory, yes, but the fact is that they don't make converters that have that low of stall speeds-so you wouldn't be able to find one. And if you could find one that would stall the engine, it would be because the engine's fueling at idle wouldn't be able to match the load that the tight converter put on it-hence, the stall. So, it would stall from park to reverse, and park to drive. Essentially, it would be like trying to be at a dead stop with a manual tranny in gear, the engine running, and the clutch engaged-i.e. it'll never happen, as the engine will just stall out.
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P.S. The good thing about a tighter converter is that you'll get better fuel economy; if it's too tight for how your tranny's built, you'll have input shaft and clutch damage.
That's OK to have your EGT's rise, because at idle with the TC load the engine has to inject more fuel to keep the idle speed the same. That's totally normal. It's exactly the same as in a gas motor-the idle mixture has to be set so that the engine idle's OK while the tranny's in gear-not in park. Otherwise the engine will stall out when you put the car into reverse or drive.

Sometimes the stator overrunning clutch can seize in the convertor, but the only way I know of to tell if that's the case is to put the truck in gear and test the stall speed-usually if the stator overrunning clutch has seized, the stall speed of the converter will be 300-400 rpm below what it's supposed to be.
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