The final flourish: A full powershift transmission

3 December 1999

The final flourish: A full powershift transmission

After four years, Renaults

Ares range is finally

available with a full

powershift transmission after

the launch of the new top-

end 800 series.

Andy Moore took to the

wheel of the flagship 815 RZ


A FULL powershift transmission could be considered to be the final jigsaw piece to complete Renaults Ares series.

Available on the new 815 RZ and the 825 RZ models, the full powershift offers 18 x 8 speeds, or 32 x 16 if the optional creep range is specified. With 12 forward speeds between 1.2mph and 7.5mph, two-thirds of the gears are within the field working range, a selection Renault claims is particularly suitable for slow speed root crop work.

Beneath the bonnet, both machines feature John Deere Powertech engines, developing 145hp for the 815 and 165hp for the 825 using an intercooler and advanced fuel injection equipment.

Unlike the semi powershift used on the 700 series, the new full version enables selection of shuttle direction control without using the clutch.

This is made possible through the revershift control lever mounted underneath the steering wheel to select forward, neutral and reverse settings.

Control of the transmission is now from a three-function control lever, which offers sequential speed selection, throttle operation and headland manoeuvring control.

In addition to the full powershift, the new range also features a park-lock safety button, designed to automatically immobilise the tractor as soon as the engine is switched off.

farmers weekly tracked down the flagship 815 RZ model working on a wet day at Maules Farm in Warks.

Compared with the former flagship 735, little has changed on the new 815 model; it has the same chunky drop-nosed bonnet and 2.88m wheelbase.

But eagle-eyed operators will notice that the wing mirror support arm has been strengthened from a round to square profile, while the less than robust plastic fenders, have been lengthened at the back to increase protection.

Renault has retained the two-door cab, the left-hand side providing good uncluttered access, the right requiring the operator to squeeze in tightly between the steering column and control console.

Inside the cab, visibility is adequate, although it could be improved by shedding two of the beefy cab pillars for a four-post cab and repositioning the bulky front air intake.

Control layout is arranged in a logical way, with the new three-function lever taking over the place of the throttle, next to the three spool levers.

Behind the levers is Renaults Tracto Control Electronic computer, available as a basic version for position, depth and mix, or as a more sophisticated format for additional automatic wheelslip adjustment.

The TCE display indicates the three-point linkage height from 0 to 100% and in the first drive, this was set to 34% enabling a 25cm (10in) ploughing depth to be maintained.

Three-point linkage adjustment is performed by the same unusual thumb-operated lever, which has three main settings – transport, raise, stop and lower.

Albeit easy to operate, a snag with the switch is that it is often accidentally flicked into the road transport position when raising the plough at headlands. As a result, it has to be reset to charge the hydraulic system so the plough can be lowered again, a time-consuming process.

In operation, after a twist of the ignition key, providing the revershift lever is in neutral and handbrake on, the engine comes to life.

The park-lock button automatically disengages when the revershift lever is lifted into forward or reverse positions.

Working to 25cm (10in) depth on light to medium land, the six furrow reversible plough provided little match for the 815s 145hp engine and proved unchallenged until 11th gear was reached.

Gear 10 was the maximum working speed with 5mph achieved at about 1800rpm. At less revs the motor stood its ground for a time but was slow to recover.

No jolting

Sequential gear shifting, which is controlled by Renaults drivetronic computer, was smooth, with progressive take-up of gears and no jolting.

At the end of the plough pass, a press of the headland manoeuvring control button on the three-function lever allowed the transmission to slowly shift down to the pre-set gear.

In the first drive, gear six was pre-selected as the manoeuvring gear and allowed enough time for the plough to be lifted and turned on a narrow headland. With an impressive 8060kg rear linkage lift capacity, the 815 lifted the fully-mounted plough with no juddering in the hydraulic system and with both front wheels firmly on the ground.

Back into work, and another press of the headland manoeuvring switch selected the previous pre-set operating gear. Again this was reached with a smooth progressive manner. &#42

Renault Ares Powershift

815 RZ 825 RZ

Engine 145hp 165hp

Trans std 18 x 8 18 x 8

Creep opt 36 x 16 36 x 16

Hyd lt/min 110 110

Lift cap kg 8,060 8,060

List price £50,600 £55,300

Making light work… the full powershift on Renaults new 145hp 815 RZ model crept up to 5mph in gear 10 – pulling a six-furrow at 25cm (10in) depth with no problem.

Cabin offers adequate visibility; the three-control lever (nearest the seat) provides throttle, sequential gear and headland manoeuvring control buttons. (Inset) The revershift offers clutchless selection of forward, neutral and reverse direction positions.

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