Tracked tractor specialist Challenger has introduced three new models to its MT700D series.

Ranging from 335hp up to 382hp, the old Caterpillar engine has been ousted for a six-pot Sisu power plant in the new US-built tractors.

Challenger reckons the new SCR-treated 8.4-litre engine is more lightweight and quieter in work than the Cat version. In reality, using an engine from its fellow Agco brand is a logical move.

The change has also seen engine service interval extended to 400 hours and the maker reckons 10% fuel savings are possible.

Looks-wise there’s very little different, other than a new oval-shaped exhaust to minimise the impact of the catalytic converters on visibility.

Underneath, more durable mid-wheels are now standard and debris deflectors should reduce chipping and damage even in harsh conditions.

The company says the mid-wheels also have more durable bearings and larger bearing cups hold more lubrication oil.

Transmission-wise the hydraulic valves that control gear changes have been recalibrated, which is said to have improved comfort between shifts.

Challenger also points out that a new power strip in the cab will provide extra connection terminals for implements and other add-ons, and it has added an intermittent wiper position for those drizzly days.

The MT700D series will be available later this year.