The Terex 82-50 tractor

The first machine to wear the markings “82-50” appeared in 1967. It was an experimental version of Euclid’s existing model 82-40 track-type tractor powered with a GM 8V-71T diesel and did not progress beyond the prototype stage.

Work on what was to become the Terex 82-50 began in earnest in 1971 when GM engineers fitted a 12V-71 engine into the frame of an upgraded 82-40EA chassis. A series of pre-production prototypes followed and these were sent into the field for rigorous testing in all types of jobs.These pre-production machines were known as Terex model 972s and differed considerably from the original project concept.

The Terex 82-50 was designed to compete with the Caterpillar D9G and also replace the company’s existing model 82-80 (TC-12), which had been in continuous production since 1955 and was, by then, quite outdated.

Production model Terex 82-50s made their debut in 1973 to much fanfare. Tipping the scales at approximately 48 tons fully equipped and powered by a GM Detroit Diesel 12V-71T turbocharged V-12 diesel putting out 370 flywheel horsepower, the 82-50 certainly sounded as powerful as it looked!

An Allison 3-speed powershift transmission turned all that horsepower into forward motion and ultimately through the usual Terex planetary final drive system.

The machine’s radiator was mounted in the rear just as with other Terex crawlers, and driven by an extension shaft from the engine.

This made the machine particularly suitable for landfill or land-clearing operations where clogging or damage to the radiator’s fins in a conventionally configured machine was a problem.

Particular care had been given to the undercarriage to make it as resilient as possible and a campaign was undertaken early on in the machine’s life to beef up the bottom roller mountings of all machines in the field when several machines experienced track rollers separating from the roller frame.

The standard undercarriage consisted of an 84” gauge track frame with an oscillation shaft for each frame just in front of the sprocket and joined at the front by a pinned equalizer bar.

38-section sealed tracks with 24” extreme service shoes were standard ex-factory but other options could be fitted at the buyer’s request.

Track tension was maintained by a nitrogen-charged, hydraulically-adjusted recoil cylinder on each track frame.

Although an open ROPS canopy was standard equipment (see picture pxx), the majority of the machines were delivered with the enclosed ROPS cab.

In a departure from traditional Terex control layout, the steering controls were mounted in a console to the operator’s left, next to the transmission control, a position that has now become the standard for almost all track-type dozers.

Visibility from the cab was average and it was not the quietest of working environments either!


Options for the 82-50 were quite varied.

The standard bulldozer blade was a 13’ 3” semi-U, and an even larger 16’ full-U could be substituted. There was also a cushioned push blade option. Terex manufactured these blades themselves. No angle blades were offered.

When it came to the ripper there were two choices, Kelly or Ateco.

By far the most popular was the Ateco 3-shank, parallelogram V-LPAS variable incidence “Vyba” model which featured dense rubber cushion blocks at the top of the ripper shanks to increase fracture rate through the ground. To date, Ateco is the only manufacturer to offer this type of ripper.

CRC-Kelly offered the massive single shank KR400 radial arc ripper which could be sunk to a depth of almost 11 feet!

A rear push plate could be fitted to the 82-50 when used in tandem scraper pushing operations and for logging the use of either a Carco 120-PS or Hyster W12E winch was the recommended fit.

Terex had quite a cadré of alternative attachment suppliers who could custom fit the 82-50 for any role and these suppliers included names such as Rockland (land clearing blades), Medford (cabs), Young (logging equipment) and Lincoln who offered one of the first automatic lubrication systems to be fitted to a track-type tractor.

Demise of the 82-50

Not a tremendously large seller for Terex, the 82-50 none-the-less did provide competition to Caterpillar and Fiat-Allis and weathered all the turbulent upheavals that beset Terex from the late 1970s onwards including the disastrous IBH takeover in 1983.

The machine was in continuous production from August 1973 until early 1986.

During this period several internal changes were made to the machine but outwardly the machine’s appearance differed little.

For the last three years of its life it was known as the D800 (to align it with the Hanomag-manufactured machines in Terex-IBH’s stable) but it was still an 82-50!

The Terex 82-50 was manufactured solely at Terex’s Hudson, Ohio, USA facility and exported worldwide.

The New Zealand Connection

At least three Terex 82-50s were imported by then-New Zealand distributor Clyde Engineering and a number of public events were held to demonstrate the machines to contractors and Government officials.

The first buyer was Feast Contractors, a long-time Terex user, followed by Carson Contracting for use in their quarry in Plimmerton, north of Wellington. The third unit was sold into the South Island but unfortunately the author does not have a record of the buyer.

Feast’s machine ultimately ended up in Downer Mining’s fleet after that company took over the Waipuna opencast site at Huntly, and that machine resides somewhere in the fill at that site.

There may have also been other Terex 82-50s imported subsequent to Clyde Engineering’s demise in 1983, as the author is aware of an 82-50 working the woodchip pile at Port of Tauranga for a number of years but is unsure from whence it came.

For the Diecast Model Collector

There is at least one model of the Terex 82-50 available.

Produced in the mid-1970s by Conrad in Germany, it is no longer manufactured but can be still obtained from auction sites such as Ebay.

It is a well-made model with Semi-U blade, ROPS cab and 3-shank ripper but is built to an uncommon 1:40th scale and, as such, does not fit comfortably into more common 1:50th scale collections.

At the time of writing, it remains the only game in town.

Brief Specifications – Terex 82-50

Engine:                          General Motors 12V-71T turbocharged V-12 diesel rated at 370 flywheel horsepower @ 2100 rpm.

Transmission:               Allison CRT7031, 3-speed full powershift transmission

Top Speed:                   7 mph in 3rd gear

Brakes:                          Oil-cooled multiple disc

Steering:                        Multiple disc clutches

Gauge:                           84”

Track:                           38-section, sealed

Std.Shoe                        24” extreme service (other options available).

Length:                          16’ 2” (bare)

Width:                           9’ 5” (bare)

Height:                          9’ 2” (to top of ROPS)

Operating Weight:        Approx. 48 tons with semi-U blade & 3-shank ripper

The Terex 82-50 crawler

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