RE5R05A Clutch Module 2002

The RE5R05A went into production in 2002, and the first cars to get it were the Infiniti Q45 with the 4.5L V8. If you are rebuilding one of those early units and the frictions came out glazed, burnt or worn down to the steel, this is a new Exedy clutch module listed for 2002 RE5R05A applications. The box in our photo is labeled Exedy EFK258, so you know exactly which kit you are getting. Exedy is a long-established Japanese clutch maker, which makes it a natural fit for a Jatco-built transmission. The kit is new and carries a 1-year warranty.

What a clutch module does in a 2002 RE5R05A

A clutch module is the set of friction plates for the packs inside the transmission. The RE5R05A is a five-speed rear-drive automatic, and it gets those five ratios by applying different combinations of clutches and brakes around its planetary gearsets. Each pack is a stack of lined friction plates interleaved with plain steel plates. When the valve body sends pressure to a piston, the stack is squeezed together and that member is locked. The friction lining is what lets the clutch take hold smoothly instead of banging in. Over time the lining wears thin, loses its texture and stops holding, especially after the fluid has been overheated. Once that happens, no adjustment or fluid change will bring it back; the plates have to be replaced.

Symptoms of worn clutches in an early RE5R05A

• The engine revs up between shifts before the next gear catches
• Slipping in one or two specific gears while the others still feel firm
• A burnt smell and dark fluid, often with friction material on the magnet
• Harsh or late shifts as the computer raises pressure to make up for the slip
• Slip or gear ratio fault codes and a jump into limp mode

How to confirm the clutches are the cause

Pull the pan and look at what is on the magnet and in the bottom. Fine black or brown material is friction lining, while bright metal suggests something harder is wearing. Check the color of the fluid as well: Sonnax notes that about half of the RE5R05A cores it receives have water intrusion from a failed cooler in the radiator, and coolant breaks down the bond between the lining and the plate. If the fluid is milky, replace or bypass the cooler or the new frictions will fail too. Finally, rule out the valve body. Sonnax reports that early Infiniti units used a low-resistance low coast solenoid of 10-15 ohms until August 2005, so a 2002 Q45 needs solenoids tested against the right value before you blame the clutches. Our RE5R05A diagnosis and service guide covers these checks.

Fitment

This module is listed for 2002 RE5R05A transmissions. That is the first model year of the unit, so it mainly applies to early Infiniti rear-drive builds such as the Q45. Clutch packs can change in plate count and thickness as a transmission is updated, so do not assume this kit matches a later truck unit. Count the frictions in each pack you remove and compare them with the plates in this kit before you begin, or send us your year and VIN and we will check fitment. For later or non-year-specific builds, see the RE5R05A clutch module listing, and find drums, pumps and kits for every year in the RE5R05A collection.

Install notes

Soak each new friction in clean ATF for at least 30 minutes before stacking it. Inspect the steel plates for heat discoloration and flatness, and replace any that are blued or warped. New frictions should always go in with new piston seals, so pair this module with a full seal and gasket set such as a RE5R05A master rebuild kit. Set each pack clearance to specification with a feeler gauge or dial indicator, and air check every piston before the drums go back in the case. Check the drums themselves for cracks and worn bushings; a damaged RE5R05A clutch drum will burn new frictions quickly. Refill with Nissan Matic-S ATF and clear the transmission adaptives so the computer relearns shift timing on the fresh plates.

Which vehicles use the 2002 RE5R05A?

The RE5R05A first appeared in 2002 in the Infiniti Q45 with the 4.5L engine. If your build date or model is different, send us your year and VIN so we can confirm this kit is the right one.

What brand is this clutch module?

It is a new Exedy kit, and the box in our photo is labeled EFK258.

Do I need anything else with it?

Yes. Install new piston seals, sealing rings and gaskets from a rebuild kit, a new filter, and replace any steel plates or drums that show heat damage or cracks.

How long should I soak the frictions?

Soak them in clean ATF for at least 30 minutes before assembly so the lining is fully saturated and does not glaze on the first apply.

What fluid goes back in after the rebuild?

Use Nissan Matic-S ATF, then clear the adaptive values and give the vehicle a full warm-up drive so shifts relearn on the new clutches.

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