do88 Transmission Cooler – Toyota GR Supra (A90) / BMW M240i / M340i / M440i / Z4 M40i (B58)

OVERVIEW

The ZF 8HP behind the B58 handles a lot of power, but the factory transmission cooler is small, and a tuned car on track or in summer traffic runs hot gearbox oil. The do88 OC-190 is a far bigger cooler for the GR Supra, M240i, M340i, M440i and Z4 M40i, with 184 percent more core volume and 176 percent more active cooling area than stock while keeping fluid pressures close to OE.

It uses harmonica-style tubes with internal channels to maximize contact between the fluid and the cooling surface, keeps the OE-style quick-connect fittings, and drops into the factory location without modification. It also works alongside the do88 WC-400 front heat exchanger.

SPECS

• Core volume 184 percent larger than OE
• Active cooling area 176 percent larger than OE
• Internally channeled harmonica tubes
• Fluid pressure kept close to OE levels
• OEM-style quick-connect inlet and outlet
• Drop-in fit; compatible with the do88 WC-400 heat exchanger
• Replaces OE 17219494828 (BMW), 32910-WAA02 (Toyota)

PARTS INCLUDED

• 1 × do88 performance transmission cooler
• 2 × caps for blocking the OE cooler connections

TECH RESOURCES

• Required extras: ZF 8HP transmission fluid to the manufacturer specification — the cooler is pre-filled with the fluid from the OE cooler plus about 3 dl extra.
• Installation instructions (do88): OC-190 B58 / GR Supra transmission cooler installation instructions (PDF)
• Installation notes: remove the plastic panels, bumper, inner wheel arches, underfloor, brake ducts and lower crash bar. Release the oil lines with a blunt tool (no sharp edges), lift the OE cooler out and cap it, trim the lower radiator guard, then fit the do88 cooler from below between the radiator and shroud.
• After install: check and set the transmission fluid level to the manufacturer's procedure.
• Instructions are shot on a GR Supra; panel removal differs on the BMW models. An assistant helps with bumper removal.
• Price is for the item only; labor is not included.

PART NUMBER

• OC-190 — do88 Transmission Cooler, BMW G-Series / Toyota GR Supra A90

VEHICLE APPLICATIONS