General Motors 2ML70 (Two-Mode)

4-speed automatic · longitudinal · 2008–2013

Also known as: 2ml70, two-mode hybrid, two mode, gm hybrid transmission

General Motors' Two-Mode hybrid transmission — in the hybrid Tahoe and Yukon.

It is not an automatic with a motor bolted on. Two electric motors sit inside the case alongside a four-speed planetary gearset, and the transmission can behave as a CVT at low speed and as a fixed-ratio automatic at high speed — which is what two-mode names, and why the catalogue's own rows describe it contradictorily as both.

That makes symptom interpretation genuinely different. A hesitation, a shunt or a change in engine note at low speed may be the transmission, or it may be the mode transition or the engine's own cylinder deactivation — three systems that feel similar and are unrelated. A scan showing no transmission fault has not exonerated it.

Its expensive failures are the motor windings and the power electronics, not the gearset, and they present electrically: a warning, reduced power, or a refusal to start the engine.

It was built in small numbers over five years, so specialist knowledge is thin and a general hybrid diagnosis is more likely to mislead than help. Establish the transmission before applying anything written about hybrids in general.

⚑ The front-drive two-mode is the 2MT70 and is a different gearbox. It was built for the transverse cars — the Vue and the Aura — where this one is longitudinal, behind the engine of a full-size truck. The catalogue does not hold the 2MT70, and a listing that offers one for the other is offering a unit that will not fit.

Cars fitted with this gearbox

2 generations. Only where a source names the model and the generation together — a gearbox is documented as a product far more often than as a fitment, so this list is deliberately shorter than the truth.

Chevrolet

Tahoe GMT900

GMC

Yukon GMT900

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

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