Caterpillar’s model 983 Traxcavator is the largest track type loader the company has ever produced in its 90-plus year history. Due to the rise in popularity of the hydraulic excavator, it is unlikely that this machine will be surpassed any time soon. By RICHARD CAMPBELL
A bit of Cat track loader background
Caterpillar’s track type loaders were originally supplied by the Trackson company and fitted as a kit to existing models in the Cat tractor range such as the D2, D4, and right on up to the D7.
In this form the various Trackson-produced machines had model numbers such as the T2, T4, HT4, T7 etc.
These early track type loaders proved to be very useful pieces of equipment – so much so that Caterpillar bought the entire Trackson Company outright in 1951 along with the trademark ‘Traxcavator’ name and began manufacturing them itself.
In order to further increase their usefulness and to strengthen the entire machine, Caterpillar engineers began the design of a dedicated track type loader which was not an adaptation of an existing track type tractor.
These modifications included a whole new chassis with a rigid track frame, higher capacity hydraulics and new loader arm geometry.
The first of the new models to appear was the 2.25 cubic yard No. 6 Shovel which was basically an interim model to test out some of the new features and gauge market acceptance.
Introduced in 1953, and broadly based on the existing Caterpillar D6-8U, the No. 6 Shovel quickly established itself as a good machine and although it was only in production for two years, Caterpillar manufactured 1613 units!
Following the success of the No. 6 Shovel, Caterpillar introduced the first three entirely new machines in its 900 series Traxcavator range in 1954 – the 933 (1 cubic yard), 955 (1.5 cubic yard) and the 977 (2.25 cubic yard) which replaced the No. 6 Shovel.
They were immediately successful and carved a niche into many segments of the earthmoving industry from landscaping to demolition.
Over the years they were continually updated and some new models added.
The 933 was discontinued in 1968 and its successor, the 931, was introduced in 1972 after a bit of a drawn-out development.
New models 951 (1.75 cubic yard) and 941 (1.25 cubic yard) came into production in 1967 and 1968 respectively and both of these remained in production until 1981.
But the industry was looking for something bigger, so Caterpillar came up with the 983 in 1969.
Designed to operate in quarries where underfoot conditions precluded the use of wheel loaders, and for bulk earthmoving and demolition, the 983 was just the ticket.
The 983 was NOT a D8 with a loader frame on it as many folks think.
It was built from the ground up as a dedicated track type loader for severe service and that is just what it did.
The first production model was the 38K series, weighing in at 35 tons and carrying a 4.5 cubic yard general purpose or rock bucket.
Power came from a Caterpillar D343T six-cylinder turbocharged diesel rated at 275 flywheel horsepower which was directly connected to a Caterpillar three-speed full powershift transmission.
A 6500 pound counterweight was fitted to the rear end of the machine to maintain balance when fully loaded if it was not equipped with a rear attachment.
For such a large machine, the Cat 983 was remarkably easy to operate, featuring pedal steering and excellent visibility all around.
Options included a cab, various rock and general purpose buckets, rippers, a Hyster winch and different widths of track shoe.
Due to strict OSHA regulations in the USA which were coming into force at the time, a ROPS canopy was made mandatory for machine Serial No. 38K1378 upwards.
As is the case with most new machines, some adjustments to the design were required early on to iron out some bugs which had manifested themselves.
These included a slight lengthening of the track frame for better longitudinal stability, lamination of the lift arms to prevent stress cracking and fitting steel instead of cast final drive covers (again to prevent stress cracking and impact damage).
The first series 983s remained in production until 1978 when they were replaced by the improved 983B model.
This featured an increase in bucket size from 4.5 to 5 cubic yards, and a weight rise from 35 to 36 tons, but the biggest change was the replacement of the precombustion chamber injection D343T engine with one of the new 3406 direct injection types, although the 275 flywheel horsepower rating was retained.
The 983B had the serial number prefix 58X.
All of the Cat 983s manufactured were equipped with Caterpillar’s tried and tested parallel linkage lift arms.
It wasn’t until the advent of the hydrostatic drive track loaders that Cat went to the Z-Bar design linkage for its track type loaders.
Unfortunately, in the early 1980s, the demand for really big track type loaders (and many types of earthmoving machinery) was tapering off due to a worldwide slump, and as an added consideration, Caterpillar had introduced a completely new line of efficient hydrostatic-drive machines beginning in 1980, making the conventional drive 983B a bit out of place in the lineup.
The 983B was discontinued in 1982, leaving the 3.5 cubic yard hydrostatic drive model 973 as the largest track type loader left in the Caterpillar track loader range, a place it still retains to this day.
The Caterpillar 983, for all its large size, was not the largest track loader ever manufactured and did have some competition.
Its principal, and pretty much only competitor, was the Komatsu D155S, a machine that Komatsu whipped up in a hurry to try and capture some sales.
This was directly based on Komatsu’s model D155A-1 track type dozer with appropriate adjustments – loader arms, rock bucket, and a rigid track frame.
Although the D155S was slightly more powerful, a little heavier (45 tons), and carried ¾ cubic yards extra in its bucket, it was sluggish and not particularly popular.
Very few were actually manufactured and they quietly went away in the late 1990s,
There are more Caterpillar 983s still active today than Komatsu D155Ss.
The New Zealand Connection
There were at least two Cat 983s imported into New Zealand and both still belong to Lendich Construction of Massey, Auckland.
The beasts are released occasionally when some serious earthmoving is required!
For the Model Collector
There are three models of Caterpillar’s big 983 available, all to 1:50 scale.
The first was released by NZG of Germany in the early 1970s. Although an older model, it still stands up well under scrutiny, though it does lack a lot of the detail found in more contemporary models.
Examples can be found on Ebay reasonably cheaply.
The other two 983s are manufactured by CCM Models of the USA and are both museum pieces.
One depicts the first production model, the 38K series with a straight GP bucket and ROPS canopy while the other is a 983B 58X series with spade-nose rock bucket, ROPS cab and ripper.
If you can find one of these good luck to you.
While they are excellent models they will not be cheap as both were made as “limited editions” and the production run was less than 1000 of each.
Brief Specifications – Caterpillar 983B
Engine: Caterpillar 3406T, 6-cylinder, inline turbocharde, direct injection diesel rated at 275 flywheel horsepower at 2060 rpm
Transmission: Caterpillar barrel type planetary powershift. 3F/3R
Top Speed: 7 mph
Steering: Two multi-disc pack steering clutches
Brakes: Oil cooled contracting band brakes
Track Frame: 92” gauge, non-oscillating
Rollers: 7 bottom rollers & 2 carrier rollers per side
Track Shoes: Standard shoe 22” double grouser
Bucket Size: 5 cubic yard spade nose rock or 5 cubic yard straight edge, heavy duty genera; purpose. Teeth on either optional.
Length: 20’ (without ripper)
Width: 9’ 6”
Height: 12’ (to top of ROPS)
Operating Weight: 38.5 tons (with rock bucket & ripper)