Transmission oil replacement for PHEV 508

[bvlenci]

Greetings everyone, I am seeking some guidance.

I am considering performing a flush and replacement of the gearbox oil on my 21 plate 508 PHEV.

Prior to proceeding, I would like to confirm whether the procedure is identical to that of standard petrol engines, or if there are specific considerations regarding electric motors.

I appreciate it.

[p00rmansp0rsche]

I believe it would be prudent to have a garage handle this task. Do you possess Diagbox, Lexia, or a comparable tool?

[p00rmansp0rsche]

https://www.amazon.com/dp/B0GVWQ2W33?ascsubtag=v1-574178-387392-d579b9af24-d

[p00rmansp0rsche]

https://www.amazon.com/dp/B01ANM9OX8?ascsubtag=v1-574178-387392-55d05970d9-d

[p00rmansp0rsche]

The Phev 508's gearbox incorporates an electric motor. The potential for electric shock complicates the proper procedures for oil replacement.

[bvlenci]

That is what I sought, thank you. I possess access to my family's garage equipped with all necessary diagnostic instruments; however, as this is my inaugural plug-in hybrid electric vehicle, I am curious about the impact of the motors.

[bvlenci]

The procedure for levelling. The gearbox lacks a dipstick. The vehicle must be positioned horizontally - even a minor incline alters the volume by several tenths of a litre. While the engine operates, the selector is shifted through R, N, and D (approximately 5 seconds each), and the fluid temperature is observed using the diagnostic instrument. At 63 ± 3 °C, the level plug is extracted: when the fluid is at the appropriate level, it flows out in a slender stream and subsequently drips - this is the moment the plug is reinserted. If nothing depletes, liquid is introduced until it commences to circulate. Certain e-EAT8 variants incorporate an additional step in the process - consult the documentation for the specific gearbox type. A cold level that has been verified is nearly always inaccurate.

I discovered this and merely require the additional step for the e-eat8 gearbox; if anyone has encountered information regarding it.

[Screwdriver_1]

A useful suggestion: ensure that the fill plug can be removed prior to draining any fluid from the gearbox.

[p00rmansp0rsche]

Comprehensive e-EAT8 Oil Change Protocol – 2018 Peugeot 508 PHEV (including references, all incorporated)

[p00rmansp0rsche]

⚠ Safety and Mode Concerns Specific to PHEVs

1. Halt the vehicle's operation in electric vehicle mode.
The 508 PHEV operates in electric mode at reduced speeds, resulting in the internal combustion engine (and consequently the gearbox) being disengaged — gear cycling and proper oil warming are not possible.

Instructions for execution:
On the mode selector (dashboard), choose Sports mode.
Engage eSave → MAX (conserves all electrical energy, compelling the engine to operate).
The Peugeot 508 manual (servicebox.peugeot.com) states: "The eSave feature allows for the reservation of all or a portion of the electrical energy… choose the amount of electrical energy to reserve: 10 km, 20 km, or the entirety of the electrical energy (MAX).

[p00rmansp0rsche]

2. Safety protocols for high-voltage (HV) systems

The e-EAT8 features an 81 kW electric motor embedded within the gearbox casing (as verified by Peugeot Australia: "The PureTech engine is paired with the e-EAT8 8-speed automatic gearbox"). Orange high-voltage cables extend from the battery located beneath the rear seat, traversing the engine compartment to the motor and gearbox.

For a drain-and-refill, you operate beneath the vehicle, distanced from high-voltage components. Nonetheless:
Refrain from handling, relocating, or detaching any orange cables or connectors. If it is necessary to detach the airbox to access the fill plug, proceed with caution around the orange wiring harness.
Detach the 12V battery located in the engine compartment prior to commencement. According to InfiniteV (AU), it is crucial to deactivate the electric vehicle prior to engaging with high voltage components. This entails detaching the 12-volt or auxiliary power supply.
According to the NSW Rural Fire Service EV protocol, "Detaching the 12V battery will deactivate certain systems/functions. Permit a duration of up to 10 minutes for the high voltage system to release electrical energy.
Wait 5–10 minutes after disconnecting before working underneath.
3. Two 12V batteries
The 508 PHEV has two 12V batteries: one in the engine bay (main, EFB) and one in the boot (auxiliary).

[p00rmansp0rsche]

To prevent the HV system from activating, it is adequate to disconnect the 12V in the engine compartment for this task. The boot battery is unnecessary for this operation.

Fluid Parameters
Metric Quantity Origin
Aisin specification AW-2 (Extremely Low Viscosity)French Car Forum threads 75816 and 83830; DS Forums thread 1084.
PSA component number 16 350 560 80 Reddit r/peugeot (reddit.com/r/peugeot/comments/1daxu73/)
Overall capacity approximately 6.5 litres
Per-drain capacity approximately 2.5–3 litres (one PHEV proprietor: 2.75 litres) Peugeot Forums t=377797
Per cycle replenishment 3–4 litres (subject to variation by source)Peugeot Discussion Boards t=377797 (3 L); French Automobile Forum t=83830 (4 L)
Cycles required: 2–3 t=341056 (3×3 L); French Automobile Forum t=86678 (3 evacuations)
Compatible aftermarket options include Ravenol ATF T-ULV and Liqui Moly Top Tec 1850.
Refrain from utilising AW-1 / JWS 3324 (EAT6 fluid).French Automobile Forum t=75816