Daihatsu Hijet S100P/S110P Fluids: Keep Your Kei Running!

Tyler Alden

Sep 10

3 min read

The S100-series Hijet looks simple underneath, but the service points change with drivetrain and transmission. This is a guide which covers S100P 2WD and S110P 4WD trucks from the 1989-1998 service-manual family. Confirm the chassis code and engine code before buying fluids.

This is a baseline guide, not a substitute for the chassis-specific service manual. Information that I could not specifically identify from the manual has been excluded with a note, rather than assumed.

Specifications

System	Application	Manual-backed specification	Quantity or interval
Engine oil	EF-NS / EF-ES	SAE 5W-30, period API SE	3.1 L; 10,000 km or 6 months
Engine oil	EF-TS turbo	SAE 10W-30, period API SF	3.1 L; 10,000 km or 6 months
Manual transmission	2WD	Grade not stated on the capacity page	1.1 L
Manual transmission / transfer assembly	4WD manual	Grade not stated on the capacity page	2.3 L, including transfer case
Transfer case	4WD automatic	SAE 75W-85, API GL-3 in the translated manual	1.6 L
Front differential	4WD	Grade not stated on the maintenance page	0.61 L
Rear differential	Standard or diff-lock layouts vary	Maintenance page confirms capacity; diff-lock section specifies SAE 90 API GL-5	1.3 L
Brake fluid	S100-series brake system	DOT 3 or DOT 4	Fill and bleed to procedure

The capacities and intervals are from the S100-S140 English service manual.

The 4WD detail that matters

On the manual-transmission S110P, the service reference lists 2.3 L for the 4WD transmission, including the transfer case. That does not mean the front and rear differentials share that oil. They remain separate service points.

The same manual lists 1.6 L for the transfer case used with the automatic transmission. Do not apply the manual-transmission quantity to an automatic truck.

RMMT baseline for an unknown-history Hijet

For a newly imported truck, RMMT would normally:

Change the engine oil and filter.
Inspect the manual-transmission oil or automatic-transmission fluid separately.
Service the transfer assembly.
Replace brake fluid and inspect the hydraulic system for leaks.
Inspect coolant condition, hoses, clamps, and the radiator cap before deciding whether to flush.
Check the washer reservoir and every visible driveline seal.

While that is our shop baseline, keep in mind that not every fluid shares the same replacement schedule.

Fill by level, not only by the bottle count

The manual states that the transmission and differential oil level should be within 0-5 mm below the fill opening. Use the listed capacity to buy enough fluid, then use the fill opening and the truck's level position to set the final level.

Always loosen the fill plug first. On an imported truck, a rounded or seized fill plug is common enough that discovering it after draining the case can end the job for the day.

A useful drain-plug reading

Look at what comes out before throwing it away. Water makes gear oil cloudy. A burnt smell or heavy metallic load can point to a problem that a fresh fill will not fix. Clean the case around the plugs before opening it, replace damaged sealing washers, and record exactly what went back in for sanity later on.

Before you order fluids

Send RMMT the chassis code, engine code, transmission type, and axle configuration. The difference between S100P and S110P is only the beginning; the transmission and axle equipment decide the final list.

Sources and verification notes

Daihatsu Hijet S100-S140 English service manual — transmission quantities on PDF page 36, engine oil on page 37, differential capacity and interval on page 39, DOT 3/DOT 4 on page 90, diff-lock oil on page 208, and transfer-case oil on page 212. This is an English service reference and should be checked against the exact chassis.
Daihatsu official gear-oil catalog — distinguishes GL-4 transmission oil from GL-5 hypoid differential oil; it is not presented as an S100P/S110P fitment table.