Classic MachinesTractors

The Terex 82-20 crawler tractor

Smallest of all the production Terex track type tractors, the 82-20 was designed to expand Terex’s market share of the crawler tractor business and take on it’s two main rivals in this class, Caterpillar and International-Harvester. By Richard Campbell

Following in the footsteps of its successful C-6/82-30, 82-40 and TC-12/82-80 track type tractors, Terex began a program around 1970 to develop a new range of machines to replace the former models with improved versions.

The end result was three machines – the 82-20 (a completely new model), the 82-30B (replacing the 82-30) and the all new 82-50 (which replaced the TC-12/82-80).

This month’s chosen subject, the 82-20, was first introduced for sale in 1973 and was intended to compete directly with the Caterpillar D7F and International TD-20C.

Featuring a General Motors 6V-71T diesel engine putting out 180 flywheel horsepower and a three speed Allison CRT5434 transmission, the 82-20 was an exceptionally clean and well- designed tractor with a very low center of gravity.

As with all Terex track type tractors, the 82-20 had a rear mounted radiator and hefty planetary final drives.

Sales of the new 82-20 were initially slow, which was understandable as Terex had not offered a track type tractor in this size category before and it took a little while for the market to catch on.

Once it did however, the 82-20 was recognized as a very able little tractor, more than capable of keeping up with the competition.

The logging community especially loved the 82-20 as it was small enough to get into selective logging stands without doing damage, yet still haul out the load of a larger tractor.

It also fitted well into big fleets, or smaller logging operation spreads.

Most 82-20’s delivered into logging were equipped with a Carco 80-PS winch and either a Terex, Rockland or Young bulldozer blade with tilt cylinder.

A fully equipped 82-20 with logging sweeps weighed approximately 19.5 tons.

As with all successful products , the manufacturer is always seeking improvements and the Terex 82-20 was no exception.

During 1976, an upgraded version of the machine was offered by Terex, the 82-20B.

This differed very little from the previous version except the GM 6V-71T engine was now delivering 205 flywheel horsepower and a lot of the electronic equipment was solid-state.

A ROPS frame or cab was now standard equipment as well.

With these alterations, an 82-20B weighed around 20 tons with blade and ripper and continued to be a popular tractor.

Dark Clouds On The Horizon

Terex-GM went through some seriously hard times in the early 1980s culminating in the disastrous buy-up in 1981 of the Terex Division by German company IBH for approx US$260m – a bargain in anyone’s language!

While General Motors were now freed of an operating unit that was losing money (due to a worldwide downturn in mining and construction), it pretty much spelled the end of new developments in the track type tractor area and, in fact, the entire Terex line as it existed.

On the surface, while business carried on as normal, IBH changed the designation of the 82-20B to the D700A (which fitted in with IBH’s smaller Hanomag D600 and D400, IBH having also acquired Hanomag’s track type tractor range).

This change of name was purely cosmetic as no actual alterations were made to the machine.

Under IBH control, the Terex line continued to haemorrhage money and IBH had to take a close look at the costs involved of producing all the different Terex models.

It was decided that the 82-20B was costing too much to manufacture versus the return on sales and the model was dropped from production in 1982, never to resurface.

Regrettably, all this was not enough to save Terex-IBH, the entire company coming to grief in mid-1983 when the banks foreclosed on the many debts IBH had, and the Company’s director, Horst Dieter-Esch, going to jail for some less than above board dealings!

While Terex eventually did survive, albeit in a very altered form, this was due to the good work of the Scottish arm of the business and a bail out by Northwest Engineering of the USA.

For the record, the 82-20 and subsequent 82-20B were only manufactured in the USA at the Hudson, Ohio plant.

The 82-20 Described

Following standard Terex practice, the 82-20 was built around an extremely strong all-welded tub into which the engine and power train were inserted.

The radiator was located at the rear of the machine behind a cast guard for protection with the fan driven by belt drive off an extension shaft and pulleys.

While this design did offer an outstanding degree of protection for the radiator (especially in landfill and logging applications) it made the operators area very hot during the summer and the radiator core was difficult to blow out when cleaning was required.

The track frames were fastened to the ‘tub’ by a pivot shaft at the rear and a pinned equalizer bar at the front which kept the track frames in good alignment and completely isolated the final drives from any form of shock loads.

Terex were known for the strength of their final drives and the 82-20 was no different to former models in the Euclid/Terex range in this respect.

Undercarriage consisted of a six-roller track frame with 40-section, 20” track shoes.

The sprockets were segmented for easy replacement.

The operator had a clean, open deck with a deeply padded seat.

Steering levers were in a console on the left side of the seat with the blade and ripper/winch controls on the left side.

A small, lockable instrument cluster was positioned directly in front of the operator set into the rear of the hood with the engine throttle control just offset to the right if the panel.

A master brake pedal and engine decelerator pedal were on the floor of the walk-through operators deck.

Visibility was excellent all around and your author can attest to what a pleasant machine the 82-20 was to operate.

Optional Equipment.

Terex offered a fully enclosed ROPS cab with heater for the 82-20 along with fast fuelling system, ether starting aid and various track shoe options up to 26” wide.

Work attachments available from Terex included the standard Variacs 200 series hydraulic control system, S-Blade, Semi-U Blade, Full-U Blade and Angle Blade.

Ateco usually supplied the rippers and Carco the logging winches.

The New Zealand Connection

Clyde Engineering, the (then) NZ distributor for Terex, imported three 82-20 tractors. The first of which was sold to John McLachlan for use around the Wellington area. John was an International-Harvester man but had recently bought a Terex S-11E from Clyde’s and appeared to like the product.

John’s 82-20 was initially put to work in the Wellington City Council quarry in the Ngauranga gorge, a baptism of fire if ever there was!

Apart from the three Clyde machines, there may have been other, private imports of the 82-20, and indeed the 82-20B as well but the author has no record of these importations if there were any.

For the Model Collector

Unfortunately there are no models of the Terex 82-20 available in any scale.

Models of Terex and the former Euclid product are very few and far between due to all manner of trademark licensing issues which is a highly regrettable situation for model collectors.


Engine:            General Motors Detroit Diesel 6V-71T turbocharged V6 rated at 180 flywheel horsepower at 2100 rpm

Transmission: Allison CRT5434 3-speed powershift

Top Speed:     7 mph

Steering:          Oil cooled multiple-disc clutches, power boosted

Brakes:            Self-adjusting multiple disc

Tracks:            40-section, 20” shoe standard

Rollers:            6 bottom, 2 top per side

Track Adj:       Hydraulic

Length:            13’ (bare)

Width:             11’ 1”

Height:           10’ 11” (to top of ROPS)

Op.Weight:     21 tons (with blade & ripper)


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