A diesel truck needs four main lubricants: engine oil, gearbox oil, axle (differential) oil and grease. Most heavy-duty diesel trucks in Bangladesh run on 15W-40 or 20W-50 engine oil, a GL-5 gear oil such as 85W-140 in the rear axle, and a lithium grease in the wheel bearings, kingpins and spring pins. Coolant and brake or clutch fluid keep the rest of the truck working. The exact grade and change interval are in your truck’s service manual, and that is always the first thing to follow. In 2026, heavy-duty diesel engine oil costs roughly Tk 650 to Tk 800 a litre and grease about Tk 1,000 a kg in Bangladesh.
This guide explains what each lubricant does, which grade to look for, when to check and change it and what it costs.
Truck lubricants at a glance
| Lubricant | Where it goes | Typical grade (check your manual) | Check | Change |
|---|---|---|---|---|
| Engine oil | Engine | 15W-40 or 20W-50, API CH-4, CI-4 or newer | Weekly, and before long trips | At the manual’s interval, with the oil filter |
| Gearbox oil | Manual gearbox | Gear oil grade in the manual, often 80W-90; GL-4 or GL-5 as specified | At each service | At the manual’s interval |
| Axle oil | Rear axle and differential | API GL-5, often 85W-140 or 80W-90 | At each service | At the manual’s interval |
| Grease | Wheel bearings, kingpins, spring pins, propeller shaft joints | Lithium-based, NLGI 2 or 3 | When you service the chassis | Re-grease at each service |
| Coolant | Radiator and engine | Coolant type in the manual, mixed as directed | Daily or weekly, engine cold | At the manual’s interval |
| Brake and clutch fluid | Hydraulic brakes and clutch | DOT grade on the reservoir cap | At each service | At the manual’s interval |
Engine oil
Engine oil keeps a film between moving metal parts, carries heat away from the pistons and bearings, holds soot until the filter or the next oil change removes it, and neutralises the acids diesel combustion produces. It does all four jobs less well as it ages.
Two numbers on the label matter. The viscosity grade, such as 15W-40 or 20W-50, tells you how thick the oil is. 15W-40 is the common grade for modern heavy-duty diesel engines, while 20W-50 is thicker and often used in older engines. The API service category, such as CH-4, CI-4 or CK-4, shows the performance standard. Newer categories are designed for newer engines; Shell Rimula R4 15W-40, for example, meets API CI-4 Plus. If the manual asks for CI-4, use CI-4 or newer, not an older category such as CF-4.
Change the oil and the oil filter together, at the interval in your service booklet, and sooner if the truck works in dust, heat, heavy loads or long idling, which describes most trucks in Bangladesh. Isuzu, for example, sets oil and filter changes every 15,000 km or 12 months for its D-MAX pickup, according to its service schedule. Old oil wears the engine and lets sludge build up, so changing engine oil on schedule costs far less than the repairs it prevents.
Check the level once a week on level ground with the engine off and cooled for a few minutes. Diesel oil turns dark quickly because it holds soot, so go by the dipstick level and the service interval, not the colour.
Gearbox oil
Most trucks in Bangladesh have a manual gearbox. Its oil keeps the gears and bearings from wearing and helps the synchronisers engage smoothly when the driver changes gear.
Gear oils use a different viscosity scale from engine oils, so an 80W-90 gear oil is not thicker than a 20W-50 engine oil in the way the numbers suggest. They also carry an API GL rating. GL-5 oils have more extreme-pressure additives for heavily loaded gears, while some gearboxes are designed for GL-4. Use exactly what the manual names for the gearbox, since the right oil for the axle is not always the right oil for the gearbox.
Signs that the gearbox oil is low or worn include hard or noisy gear changes, a whine that rises with speed and oil on the underside of the gearbox. Check for leaks at every service and top up to the level plug.
Axle and differential oil
The rear axle carries the full weight of the load and turns the drive through 90 degrees in the differential. Its hypoid gears slide as well as roll against each other, which needs a gear oil with strong extreme-pressure additives. That is why axle oils are almost always API GL-5.
The common grades are 85W-140 and 80W-90. Mobil’s Delvac TM Genuine Axle Oil 85W-140, for example, meets API GL-5 and is made for rear axles and live front axles designed by Tata Motors. Check what your manual names before you buy.
Heavy loads, steep ramps and stop-start city work all heat the axle oil and wear it out faster. Overloaded trucks put the axle under the most strain of all. Check the level at the filler plug at each service, look for oil on the inside of the wheels, which can mean a leaking hub seal, and listen for a whine or clunk from the rear on the move.
Grease
Grease is oil held in a thickener, so it stays in place on parts that oil would run off. A truck has many of them:
- wheel bearings;
- kingpins and steering joints;
- spring pins and shackles;
- propeller shaft universal joints and the slip joint;
- clutch and brake linkages;
- the fifth wheel on a prime mover.
Most truck greases use a lithium thickener. The NLGI number shows how stiff the grease is: NLGI 2 is the common general-purpose grade, and NLGI 3 is stiffer. Shell Gadus S2 V220 2, a lithium NLGI 2 grease, is rated from -20°C to 100°C and up to 120°C for short periods. The MAK greases sold in Bangladesh are NLGI 3.
Greasing is simple but often skipped. Wipe each nipple clean first, then pump grease in until fresh grease pushes the old grease out of the joint. Wipe off the excess, because it collects dust. Keep grease away from brake linings and the rubber parts of hydraulic brakes, which the Shell data sheet also warns about. A dry spring pin or kingpin wears quickly, makes the truck pull or wander and can end in a broken spring.
Coolant
Coolant is not a lubricant, but it is the other fluid that keeps the engine alive. Use the coolant type the manual names, mixed with water as directed, rather than plain water. Coolant raises the boiling point and stops rust and scale building up inside the engine and radiator, which matters in Bangladesh’s summer and in traffic jams.
Check the level when the engine is cold. Never open a hot radiator cap, because the coolant is under pressure and can scald. A level that keeps dropping points to a leak or a failing head gasket, and white smoke or milky engine oil means coolant may be getting into the engine.
Brake, clutch and power steering fluids
Pickups and light trucks usually have hydraulic brakes and clutch. They use brake fluid of the DOT grade printed on the reservoir cap, usually DOT 3 or DOT 4. Brake fluid absorbs moisture from the air over time, which lowers its boiling point, so change it at the interval in the manual and never top it up with engine oil or anything else.
Heavy trucks mostly use air brakes. They need no brake fluid, but the air tanks collect water, so drain them as the manual directs, usually every day. Power steering, where fitted, uses the fluid the manual names, often an automatic transmission fluid. Tipper trucks also have a hydraulic system for the body that uses its own hydraulic oil.
How to choose the right lubricant
- Start with the manual. It names the viscosity grade and specification for each part. If you no longer have it, ask the dealer for your model.
- Match the specification, not the brand. Any oil that meets the API category and grade the manual names will do the job.
- Do not mix grades. Top up with the same oil. If you must use something else in an emergency, change to the right oil at the next service.
- Buy sealed packs from authorised dealers. Check that the seal and the label are intact, since fake lubricants do reach the market.
- Keep a record. Write the date, odometer reading and oil used at every service. It keeps the truck on schedule and helps if you sell it.
Truck lubricant prices in Bangladesh in 2026
| Product | Grade | Pack | Price (Tk) | Per litre or kg (Tk) |
|---|---|---|---|---|
| MAK Platinum Plus | 15W-40, API CI-4 Plus | 15 L | 10,393 | about 693 |
| MAK TATA Motors | 15W-40, API CI-4 Plus | 15 L | 11,908 | about 794 |
| MAK Diamond Plus | 15W-40, API CH-4 | 15 L | 10,393 | about 693 |
| MAK Gold MG | 20W-50, API CH-4/SJ | 20 L | 13,858 | about 693 |
| MAK MP3 Grease | NLGI 3 | 18 kg | 17,562 | about 976 |
| MAK RUBY Grease | NLGI 3 | 12 × 1 kg | 11,830 | about 986 |
Prices are from TL Shop, Truck Lagbe’s online shop, when the items were listed as sold out, so confirm the price before ordering. Larger packs cost less per litre or kg. Bangladesh’s lubricant market reached about Tk 8,000 crore in 2024, double its size five years earlier, The Daily Star reported, and prices have risen with fuel prices, the exchange rate and import duties.
Dispose of used oil safely
Used engine and gear oil is toxic. Do not pour it into drains, soil or water. Let the workshop handle it, or collect it in a sealed container and give it to a dealer or collector who takes used oil. Wear gloves, and let the engine and axle cool before draining.
Keep your truck on the road with Truck Lagbe
Lubricants work best as part of a regular maintenance routine that also covers brakes, tyres and filters. Order engine oil and grease from TL Shop, and find trips for your truck on the Truck Lagbe Owner app.
Frequently asked questions
What lubricants does a truck need?
Engine oil, gearbox oil, axle (differential) oil and grease, plus coolant and brake or clutch fluid. Your service manual lists the grade for each.
Which engine oil is best for a diesel truck in Bangladesh?
The grade and API category your manual names. Many modern diesel trucks use 15W-40 to API CI-4 or newer, while older engines often use 20W-50.
What gear oil goes in a truck’s rear axle?
Usually an API GL-5 gear oil, often 85W-140 or 80W-90. Check the grade in your manual.
How often should I grease my truck?
At every service, or more often if the truck works in dust, mud or water. Pump grease into each nipple until fresh grease pushes the old grease out.
Can I use engine oil instead of gear oil?
No. Gear oil has extreme-pressure additives that engine oil does not, and the axle and gearbox need them.
How much does truck engine oil cost in Bangladesh?
Heavy-duty diesel engine oil costs roughly Tk 650 to Tk 800 a litre in 2026, depending on brand, grade and pack size.
