Torque convertor question
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Elder User
Joined: Dec 2007
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From: royal oak, mich
Torque convertor question
I've read in an article written around 1997 that stated the stock lockup convertor in the 4R70 trans will balloon after 5400 rpm. Any one know if the newer trucks, 2002, has been fixed? The tuners you buy allow you to turn off the speed limit so getting above 5400rpm is ez now. I think I've wound mine up to 5600 rpm on occasion but haven't noticed any ill effects. <!-- / message --><!-- sig -->__________________
Senior User
Joined: Jul 2008
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It isn't anything that the factory considers a problem so it wasn't 'fixed'. the only real solution is to get an aftermarket converter that can handle what you are asking of it.
Also, you need to be careful. You won't notice any ill effects until it's too late. This 'problem' doesn't give any warning that it is going to finally happen. Over time with running the converter to where it is ballooning a little the metal fatigues and it balloons even more at a lesser rpm. Eventually it balloons enough that either the thrust washer or thrust bearing falls out and starts eating on the stator support. This causes the immediate need for an ugly transmission repair which often ends up being a complete replacement because of the total contamination from the failure. If it balloons enough you also get to enjoy the expense of an engine repair because it jams the crankshaft forward into the engine and hoses up all kinds of things.
My advice, don't do that.
Darrin
Also, you need to be careful. You won't notice any ill effects until it's too late. This 'problem' doesn't give any warning that it is going to finally happen. Over time with running the converter to where it is ballooning a little the metal fatigues and it balloons even more at a lesser rpm. Eventually it balloons enough that either the thrust washer or thrust bearing falls out and starts eating on the stator support. This causes the immediate need for an ugly transmission repair which often ends up being a complete replacement because of the total contamination from the failure. If it balloons enough you also get to enjoy the expense of an engine repair because it jams the crankshaft forward into the engine and hoses up all kinds of things.
My advice, don't do that.
Darrin
