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Old 05-16-2017, 10:35 PM   #6
clinebarger
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Join Date: May 2009
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Posts: 6,255
Re: 4l80e compatibility with 4.8/5.3

Quote:
Originally Posted by FAKKY View Post
Assume if you got a 4l80e with original 4l80e flexplate and spacer and bolts would be a direct swap (just remove the 4l60e flexplate)
That is correct

How much do you like an aftermarket converter over stock. Truck will be sub 300 HP for a while ....... so spending an extra $700 on a aftermarket convertor doesnt seem necessary. If you have to sepnd $50 on a new flexplate and $50 on spacers/bolts ...... if using donor flexplate/spacer is not an option ...... might be better just ponying up the $$ though.
It depends on the Combination & Use of vehicle.
For a performance vehicle, A higher stall is necessary. With a low torque engine like a 5.3L.....The weight of a stock 4L80E converter, Real low stall speed, And the 2.48 1st gear ratio is going to be very detrimental to performance.....Especially out of the hole.

The internal transmission components that have to be accelerated up to speed in a 4L80E in first gear have a lot of heft!

The Overdrive Carrier & Hub , Forward Drum , These are directly driven by the Input Shaft.
The Direct Drum is spun in the opposite direction at 87% of engine speed.
This is easily 40# of weight that has to be accelerated from a dead stop, Then you have a 70# converter......

If your engine makes max torque at 2950, The best thing for performance & acceleration would be a 3000 rpm or a little higher stall converter in the smallest diameter possible.
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