Flywheel or Flexplate

[TallPaul]

With a manual transmission you have a flywheel, but I was told today that the same part with an automatic is called a flexplate. Is this so and why?

 

[srivett]

Yep, it's true. I'm waiting on the reason too. I've seen them both in the flesh and don't understand it seeing as a manual transmission will have lots of springs between it and the engine while an automatic won't have any springs.

Steve

 

[TooManyWheels]

An automatic does not need the flywheel effect because it has a torque converter, which performs the same energy storage function, so it's understandable that an automatic's corresponding part would not necessarily have the same name.

And flex plates do flex, in fact they have been known to flex so much that they crack. But I will admit I don't understand why. I don't believe it is to compensate for misalignment between the engine and transmission, because the front bushing in an automatic will wear long before a flex plate will flex. Perhaps it is to absorb front to back movements of the converter generated by the input shaft during shifting.

 

[mechtech]

The flexplate absorbs the crankshaft pulses. A heavy flywheel does the same thing, by a different method [mass].

 

[Steve S]

A flexplate is used with an automatic transmission. The flywheel is used with a manual transmission . Look at the jegs or summit racing website for pictures of the parts.

 

[eljefino]

A flexplate is as flexible as a floppy disk is floppy.

 

[andyd]

quote:

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Originally posted by eljefino:
A flexplate is as flexible as a floppy disk is floppy.

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yep , but when they start getting floppy, where's the release button?

Broken flexplates are a common malady on the old AMC era 360 v8/ 727 combo found in the grand wagoneers, etc. They sound terrible and are a PITA to replace. Eventually the plate will separate entirely and the car will not move. AMHIK