ACDelco is the OE supplier. Sonnax makes upgraded HD aftermarket parts. For the 4L80E specifically, the choice depends on whether you have shudder, soft shifts, or a clean rebuild.
Direct OE replacement. Same spec as the original. Comes in a sealed package, factory tested. Best for: clean rebuilds where the customer is not towing heavy and the transmission was healthy when it came in.
Upgraded coil winding, stronger spring tension, better magnetic core material. Built to handle higher line pressures from tow trucks, motor homes, and modified vehicles. Best for: any 4L80E that was failing before — Sonnax HD removes the original failure point.
ACDelco: stock vehicle, no tow load, original transmission healthy.
Sonnax HD: tow rig, motor home, lifted truck, anything that hauls weight or runs higher pressure than stock.
ACDelco averages $80-120. Sonnax HD averages $130-180. The Sonnax upcharge is worth it on any vehicle that pulls a trailer or sees commercial use.
Direct-from-the-pro pricing. Free shipping over $75. Same-day handling Monday-Friday.
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