RE5R05A Pump

A Nissan Frontier, Xterra, Pathfinder, Titan or Armada, or an Infiniti QX56, that hesitates going into gear, flares between shifts and gets worse the longer it is driven usually has a pressure problem, and pressure starts at the front pump. This is a used original RE5R05A front pump assembly for owners and shops that have already confirmed the pump is worn and want a factory pump at a fraction of the price of a new one from a parts counter.

What the front pump does in the RE5R05A

The RE5R05A uses a gear-type pump bolted to the front of the case, driven directly by the torque converter hub. It runs any time the engine runs and supplies all the oil the transmission uses: the line pressure that applies the clutches and the brake band, the feed for the converter clutch, and the lube flow that keeps the planetaries and bushings alive. The valve body and the line pressure solenoid can only regulate what the pump delivers. If the pump cannot keep up, the computer can command all the pressure it wants and the clutches will still apply soft and slip.

Symptoms of a worn RE5R05A pump

• Slow, mushy engagement into Drive and Reverse, especially when the truck has sat overnight
• A whine that tracks engine speed, often loudest cold, as worn clearances pull air into the fluid
• General slipping in all gears instead of one bad shift
• Overheated, dark fluid, because low pressure lets clutches slip and make heat
• Poor converter clutch lockup or shudder on the highway

Not every pressure complaint is the pump. Shift solenoid faults are the most common RE5R05A codes, in the P0750 to P0770 range, and P0745 points at the line pressure control solenoid. If you have one of those codes, test the solenoid first. A replacement pressure control solenoid costs far less than pulling the transmission.

Confirm the diagnosis

A gauge on the line pressure port is the only real test. Take a reading cold and again at operating temperature. A pump with worn gears and pocket loses more as the fluid thins, so the hot reading falls well below the cold one. A pressure regulator or solenoid problem tends to be wrong at every temperature. Before you condemn the pump, rule out the pilot valve bores in the valve body, which Sonnax documents as feeding the line pressure and shift solenoids and which can read exactly like a weak pump. Our RE5R05A service guide lays out the order to test in, plus how to spot coolant in the fluid from a failed radiator cooler, a common way these pumps get scored.

Fitment

This listing is sold as an RE5R05A pump without a specific model year attached. The transmission was built from the early 2000s through the late 2010s and picked up revisions along the way, so check it against the pump you are removing: compare the outside casting, the bolt holes and the stator shaft before installation, or give us your year and VIN and we will confirm it. If you already know your year, we also stock a 2007 RE5R05A pump and a 2003-2006 RE5R05A pump. All RE5R05A parts are listed on our RE5R05A transmission page.

Install notes

• Install a new front seal and inspect the bushing. Roll the converter hub under a light and replace the converter if the hub is grooved where the seal rides.
• Look at the sealing ring grooves on the stator support. Ring lands on these units wear in a stepped pattern that the eye misses, and Gears Magazine traced a harsh 1-2 shift to that wear on an RE5R05A support.
• Draw the pump into the case evenly, lube the gears with fresh ATF, and make sure the converter drops fully onto the pump drive before you mate the engine.
• Fill with Genuine Nissan Matic S ATF and set the level hot using Nissan's check procedure.
• A pump that wore out usually ran on bad fluid that also hurt the clutches. Pair it with our RE5R05A overhaul kit if the case is open, and replace the radiator cooler if there is any sign of coolant.

Which vehicles use the RE5R05A pump?

The RE5R05A went into Nissan Frontier, Xterra, Pathfinder, Titan and Armada trucks and the Infiniti QX56, among other rear-drive Nissan and Infiniti models. Confirm your transmission and send us your year and VIN if you are unsure.

This listing has no year. How do I know it fits?

Compare the casting, bolt pattern and stator shaft with the pump you are taking out. If you would rather we check, send your year and VIN before ordering. We also carry year-specific 2003-2006 and 2007 versions.

Can a bad line pressure solenoid look like a bad pump?

Yes. P0745 points at the line pressure control solenoid, and worn pilot valve bores can also cause low pressure. Test the solenoid and valve body side before pulling the transmission for a pump.

Do I need to relearn anything after replacing the pump?

The pump itself needs no programming, but if the valve body or transmission control module is replaced at the same time, follow the Nissan procedure for that part. Drive it to full temperature before judging shift quality.

What fluid should I use?

Genuine Nissan Matic S ATF, with Matic J as Nissan's approved alternative. Do not use Matic D in the transmission; Nissan specifies that for the transfer case on 4WD trucks.

• Nissan/Infiniti RE5R05A Transmission Service Guide: Pathfinder, Armada, QX56