Terex 820-TX980B Workshop Manual 6111283M2 — Wiring Diagrams

Be realistic about the era: these are mostly mechanical machines with no OBD-style port and no engine ECU code list. The one electronically controlled gearbox in the range, the Carraro TLB2 Powershift, does have its own error codes in the transmission section, read as blink/display codes from the transmission controller, with the checks that go with them. For the rest of the machine, diagnosis is done the old way, with the wiring diagrams and test values in the Electrics section and the pressure and cycle time figures in the hydraulic sections. p. 1432

No, and you should know that before buying. The Engine section is removal and installation only; the book itself tells you to refer to the Perkins Engine Manual for internal work. You still get the working data: the 1104C-44T is a 4.4 litre turbo four, 105 x 127 mm bore and stroke, 7.3 litres of oil, and 68.5 kW on the 820 or 74.5 kW on the 860 to 970 models. For a bottom-end rebuild, pair this book with the Perkins 1104C manual. Everything from the flywheel back is covered here in full. p. 1536

Yes, and this is the classic complaint on these machines: a chafed harness or hidden short that drains the batteries while it sits. The Electrics section carries the wiring diagrams and the fuse and relay board layout, so you can isolate circuits one at a time instead of stripping tin off the whole machine hunting by feel. It also gives the charging system check: 14.0 to 14.4 V at the battery, with the alternator output test to run if the reading falls outside that. p. 374

Yes. The Main Hydraulics section gives the factory figures: pump 1 delivers 80 l/min at 225 bar, pump 2 delivers 62 l/min on the 820 or 80 l/min on the 860 to 970, at 207 bar. It also lists cycle times measured at 1800 rpm with the oil at 50-60 C: the front loader beam raises in 9.5 seconds on pump 1 alone or 5.3 seconds on both pumps, while the backhoe boom takes 5.8 and 4.0 seconds. A stopwatch and a gauge tell you whether the pump is tired before you spend money on it. p. 288

Each section carries its own torque data. As a sample from the front axle: wheel hub 230 Nm (170 lb.ft), king pin 190 Nm (140 lb.ft), swivel joint 300 Nm (221 lb.ft). The book carries six axle sections in all, four front and two rear, covering two and four wheel drive and two and four wheel steer variants, plus separate Steering and Wheels and Tyres sections, so the fastener specs for hub and steering work are where you need them instead of in a search engine. p. 649