Partial oil change in automatic transmission <em>Nissan Pathfinder R51</em> 2.5 diesel: instructions for owners

Owners Nissan Pathfinder R51 with diesel engine 2.5 dCi (YD25DDTi) are often faced with the question: how to extend the life of an automatic transmission RE5R05Ainstalled on these machines? A complete oil change in an automatic transmission is an expensive and time-consuming procedure that requires special equipment. But partial replacement - an affordable way to keep the box in working condition, especially if the mileage has not yet exceeded 150–200 thousand km.

But here lies the catch: the wrong approach to partial replacement may not only not improve, but also worsen the condition of the automatic transmission. For example, mixing incompatible fluids or mistakes when draining old oil often lead to jerks when shifting gears or accelerated wear of the clutches. In this article we will look at why for Pathfinder R51 it is critical to use exactly Nissan Matic S or its analogues with approval JWS 3309, how to drain the oil correctly without the risk of damaging the pan, and why the box may need to be adapted after replacement.

Why a partial oil change in an automatic transmission? Pathfinder R51 - not always the best choice

Many owners believe that a partial oil change is the “golden mean” between a complete replacement and completely ignoring the problem. However for Nissan Pathfinder R51 with box RE5R05A this is not always the case. The fact is that with a partial replacement, only the 30–40% liquid, and the rest remains in the torque converter, radiator and valve body channels. If the old oil has already lost its properties (it has darkened, smells like burning, contains metal shavings), then mixing it with new oil will only give a temporary effect.

Moreover, in boxes Pathfinder R51 after 2008 release, a problem with contamination of solenoids (especially solenoid TCCresponsible for locking the torque converter). A partial oil change may temporarily improve transmission performance, but if the solenoids are already clogged with deposits, they will need to be cleaned or replaced. In such cases, a partial oil change is more of a “cosmetic” repair rather than a solution to the problem.

• ⚠️ When partial replacement is useless:
• 🔧 If the oil in the automatic transmission is black and has a strong burning smell, this is a sign of severe wear of the clutches. This requires a complete replacement with flushing.
• 🔧 If the transmission “kicks” when switching from 1st to 2nd gear, the problem may be in worn solenoids, and not in the oil.
• 🔧 If the mileage exceeds 200 thousand km, and the oil has never been changed, a partial replacement may cause clogging of the hydraulic unit with deposits.

However, a partial oil change in the automatic transmission Pathfinder R51 justified in the following cases:

• ✅ Mileage up to 150 thousand km, oil light or slightly darkened.
• ✅ The box works smoothly, without jerks or delays.
• ✅ The previous oil change was no more than 60 thousand km ago.

What kind of oil to fill in automatic transmission Nissan Pathfinder R51 2.5 dCi

For the box RE5R05A, installed on Pathfinder R51 with diesel engine 2.5 dCi, the manufacturer recommends using only Nissan Matic S (article KE908-99932). This oil meets specification JWS 3309 and has optimal friction properties for this box. The use of other fluids, even with similar characteristics, may result in:

• 🔥 The box will overheat due to incorrect viscosity.
• 🔧 Accelerated wear of friction discs.
• ⚡ Incorrect operation of solenoids and hydraulic unit.

If the original oil Nissan Matic S not available, you can use analogues that meet the specifications JWS 3309:

Manufacturer	Oil name	Article	Notes
Idemitsu	ATF Type J	30450015-006	Complete analogue of Nissan Matic S, often used in services
Ravenol	ATF JWS 3309 Fluid	4014835734542	High-quality analogue, suitable for severe operating conditions
Liqui Moly	Top Tec ATF 1800	7502	Universal oil, but requires confirmation of compatibility with JWS 3309
Mobil	ATF 3309	152646	Nissan approved, but less common than the original

Important: even if you use analogue, do not mix different brands of oils in one box. If you do not know what kind of oil was filled previously, it is better to complete replacement with washing.

⚠️ Attention: In boxes Pathfinder R51 After the 2010 release, sometimes there is a modification of the valve body that requires oil with improved anti-friction properties. If your car was manufactured after 2010, check the gearbox version by VIN code before purchasing oil.

Tools and materials for partial oil change in automatic transmission

For independent partial oil changes in automatic transmissions Nissan Pathfinder R51 you will need:

Fresh Nissan Matic S oil (or equivalent) - 4–5 liters

New automatic transmission filter (part number 31397-31X02) - optional, but recommended

Pan sealing gasket (article 31397-1X010)

10 mm wrench and 10 mm socket for drain plug

14 mm socket wrench for pan bolts

Funnel with a long spout or oil syringe

Container for draining old oil (at least 5 liters)

Rags and carburetor cleaner for cleaning the pan

Torque wrench (optional, for proper bolt tightening) -->

Pay special attention automatic transmission filter. In boxes RE5R05A the filter is a metal mesh that becomes clogged with wear products over time. If you change the oil for the first time after 100 thousand km, the filter definitely needs to be replaced. If partial replacement is carried out regularly (every 40–60 thousand km), the filter can be left as old, but washed thoroughly in a cleaner.

Also be prepared for the fact that Pathfinder R51 The automatic transmission drain plug often sticks. To unscrew it, you may need:

• 🔧 Penetrating lubricant (e.g. WD-40 or Liqui Moly MoS2).
• 🔧 Impact wrench (if the cork cannot be removed manually).
• 🔧 New drain plug (item no. 31377-31X00) - in case the old one is damaged.

Step-by-step instructions: how to drain old oil from an automatic transmission

The process of draining oil from an automatic transmission Pathfinder R51 has its own nuances. Main rule: do not drain the oil “when it’s cold”, otherwise there will be too much old liquid in the box.

Step 1. Preparing the car

• 🚗 Place the car on a flat surface (best on a lift or overpass).
• 🔧 Turn off the engine and set the parking brake.
• 🔧 Remove the crankcase protection (if there is one).

Step 2: Drain the oil

1. Locate the drain plug on the automatic transmission pan (it is located closer to the back of the box).
2. Place the drain container and carefully unscrew the plug with a 10 mm wrench. Be careful - the oil will be hot!
3. Let the oil drain completely (this will take 5-10 minutes).
4. If you plan to change the filter, unscrew the pan bolts (14 mm) and carefully remove it. Up to 0.5 liters of oil may remain in the pan - be prepared for this.

Step 3. Cleaning the pan and replacing the filter

• 🧹 Thoroughly clean the tray of deposits and metal shavings. Use carburetor cleaner and a rag.
• 🔧 If you are replacing a filter, carefully remove the old one and install a new one. The filter is secured with 3 bolts (10 mm).
• 🔧 Check the condition of the magnets at the bottom of the pallet - they collect metal shavings. If the magnets are very dirty, clean or replace them.

⚠️ Attention: If you find a large amount of metal shavings or pieces of friction clutches in the pan, this is a sign of serious wear and tear on the box. In this case, a partial oil change can only aggravate the problem - contact the service for diagnostics.

How to properly fill new oil into an automatic transmission

Filling new oil in the automatic transmission Pathfinder R51 - the process is more labor-intensive than draining. The main difficulty is that in this box no traditional dipstick to check the level. Instead it is used control pluglocated on the side of the box.

Step 1. Filling with oil

• 🔧 Find the filler hole (it is located on top of the box, next to the battery). In some modifications Pathfinder R51 The filler hole is covered with a plastic cap.
• 🔧 Use a funnel with a long hose or a large syringe to pour in the oil. Fill approximately 3.5–4 liters (this is the amount of oil drained).

Step 2: Checking the Oil Level

• 🔧 Start the engine and warm up the box to operating temperature (60–70°C). To do this, you can drive a few kilometers or let the car idle for 10–15 minutes.
• 🔧 Place the car on a flat surface and move the automatic transmission selector through all positions (P-R-N-D), holding each position for 2-3 seconds.
• 🔧 Find the control plug (it is located on the side of the box, closer to the front bumper). Unscrew it with a 10 mm wrench.
• 🔧 If oil begins to drip from the hole, the level is normal. If not, add another 100–200 ml and repeat the test.

Step 3. Final steps

• 🔧 Tighten the inspection plug to torque 35–40 Nm (do not overtighten!).
• 🔧 Reinstall the crankcase protection (if removed).
• 🔧 Reset automatic transmission adaptations (read about this in the next section).

What to do if the oil is overfilled?

If you accidentally fill in too much oil, its excess can lead to increased pressure in the box and squeezing out the seals. To drain excess oil:

1. Warm up the box to operating temperature.

2. Unscrew the control plug and allow the excess to drain.

3. If the oil does not drip, carefully tilt the car towards the plug (for example, by jacking up the right front wheel).

4. After draining the excess, tighten the plug and check the level again.

Is it necessary to reset automatic transmission adaptations after changing the oil?

After changing the automatic transmission oil Nissan Pathfinder R51 Many owners are faced with the fact that the box begins to work “jerky” or with delays. This is due to the fact that the electronic control unit (ECU) of the box adapted under the old oil, and now it needs time to “get used” to the new fluid.

In most cases, adaptations are reset automatically after 100–200 km. However, if shifting problems persist, you can reset the adaptations manually. There are two ways to do this:

• 🔧 Reset via diagnostic connector (OBD-II):

Use a scanner (eg Launch X431 or Delphi DS150E) and select the function AT Adaptation Reset in the automatic transmission menu. This method is the most reliable, but requires diagnostic equipment.

• 🔧 Manual reset (method for experienced owners):

Disconnect the battery terminal for 10-15 minutes, then connect it back. Start the engine, warm up the transmission and drive 5–10 km, avoiding sudden acceleration. This method is less effective, but can help in mild cases.

⚠️ Attention: If, after resetting the adaptations, the box continues to operate incorrectly (for example, it “freezes” in one gear or shifts with a shock), this may indicate a malfunction of the solenoids or valve body. In this case, diagnostics at the service center is required.

Common mistakes when partially changing automatic transmission oil Pathfinder R51

Even experienced car owners sometimes make mistakes when changing automatic transmission oil. Here are the most common ones that can lead to serious problems:

• ❌ Using the wrong oil. For example, fill Dexron III or ATF+4 instead of Nissan Matic S. This leads to slipping of the clutches and accelerated wear of the box.
• ❌ Insufficient heating of the oil before draining. The cold oil does not drain completely, and too much old fluid remains in the box.
• ❌ Overfilling or underfilling oil. Both options are dangerous: underfilling leads to oil starvation, and overfilling leads to squeezing out the seals.
• ❌ Ignoring filter replacement. An old clogged filter cannot ensure normal oil circulation, which leads to overheating of the box.
• ❌ Incorrect tightening of pan bolts. Too loose a tightening will cause leakage, and too tight a tightening will cause the pan to deform.

Another common mistake is failure to check oil level after replacement. In boxes Pathfinder R51 Without a dipstick, many owners rely on the “eye gauge,” but this is fraught with consequences. For example, if the oil is underfilled by 200–300 ml, this can lead to:

• 🔥 The box overheats when driving in traffic jams.
• 🔧 Accelerated wear of bearings and gears.
• ⚡ Loss of pressure in the valve body and “kicks” when changing gears.

To avoid these problems, always check your oil level on a warm box through the control plug.

FAQ: Frequently asked questions about changing automatic transmission oil Nissan Pathfinder R51

Can Nissan Matic S be mixed with other oils?

No, mix Nissan Matic S with other oils (for example, Dexron VI or ATF+4) is strictly not recommended. These fluids have different additive packages, and mixing them can lead to:

• 🔥 Loss of frictional properties of oil.
• 🔧 Formation of deposits in the hydraulic unit.
• ⚡ Unstable operation of solenoids.

If you do not know what kind of oil was filled previously, it is better to complete replacement with washing.

How much oil is needed for a partial change in an automatic transmission? Pathfinder R51?

For partial oil change in automatic transmission Nissan Pathfinder R51 with box RE5R05A will be required 4–4.5 liters new fluid. This amount depends on how much oil was drained. Usually about 3.5–4 liters flow out of the box, but if you removed the pan and changed the filter, the volume can increase to 4.5 liters.

Important: always have a supply of oil (at least 1 liter), as topping up may be required after checking the level.

How often should you change the automatic transmission oil? Pathfinder R51 2.5 diesel?

Manufacturer (Nissan) claims that the oil in the automatic transmission RE5R05A filled for the entire service life. However, in practice this is not the case. Recommended replacement intervals:

• 🔧 Light operating conditions (city, highway, temperate climate): every 60–80 thousand km.
• 🔧 Difficult conditions (frequent traffic jams, off-road conditions, extreme temperatures): every 40–50 thousand km.
• 🔧 If the oil has never been changed (mileage over 150 thousand km): required complete replacement with washing.

What happens if you don’t change the automatic transmission oil? Pathfinder R51?

Ignoring automatic transmission oil changes Nissan Pathfinder R51 leads to the following problems:

• 🔥 Box overheating due to the loss of heat-removing properties by the oil.
• 🔧 Friction wear and gear slippage.
• 🔧 Clogged solenoids and valve body with wear products.
• ⚡ Jerks and blows when changing gears.
• 💥 Complete box failure (requires major repairs or replacement).

Automatic transmission repair cost RE5R05A can reach 150–200 thousand rubles, while regular oil changes cost 3–5 thousand rubles (including materials).

Is it possible to do a complete oil change in an automatic transmission? Pathfinder R51 without a device?

Yes, complete automatic transmission oil change Nissan Pathfinder R51 can be done without a special device, but it will require more time and effort. The method is called "double or triple partial replacement" and is as follows:

1. Perform a partial oil change (drain and fill with new oil).
2. Drive 50–100 km for the new oil to mix with the old.
3. Repeat the drain-fill procedure 2-3 times.

This method allows you to update 80–90% oil in the box, but it requires 12–15 liters of liquid and a lot of time. Also after such a replacement you definitely need to reset the adaptations Automatic transmission.