Looking at the trending questions, I'll pick two strong topics:
- Nissan Patrol auto transmission problems (questions 8 & 9, multiple users asking the same thing, hugely popular vehicle in AU)
- P0753 and P0713 transmission fault codes (questions 12 & 13, multiple users, good SEO for code-specific searches)
title: "Nissan Patrol Auto Gearbox Slipping in 5th Gear: What's Going On" slug: "nissan-patrol-auto-transmission-problems" description: "GQ and GU Nissan Patrol auto gearbox slipping, slow shifts, and burnt fluid smell explained, with repair costs in AUD and USD." date: "2026-04-16" category: "Troubleshooting" keywords: "Nissan Patrol auto transmission problems, GU Patrol gearbox slipping, RE4R03A rebuild cost, Patrol 5th gear slip, burnt transmission fluid" author: "TorqueBot Team"
The GQ and GU Patrol are legends. They go places other wagons only dream about, and they're still running decades after most modern SUVs would've been scrapped. The automatic gearboxes, though, are starting to show their age.
5th gear slippage, sluggish shifts, burnt oil smell. These three symptoms together point at a gearbox that's getting tired.
Which Gearbox Does the Patrol Use?
The GQ Patrol (1988-1997) uses the Nissan RE4R01A in petrol models. The GU Patrol (1997-2013) runs the RE4R03A across most petrol and diesel variants, with later V8 models using the RE5R05A.
Both the RE4R01A and RE4R03A are four-speed automatics. They were solid units for their time, but they're now 25-35 years old. High-kilometre examples are showing it.
What Does "5th Gear Slippage" Actually Mean?
Here's the confusing part: these gearboxes only have four forward gears. When Patrol owners describe "5th gear" slipping, they usually mean the overdrive gear (4th with the overdrive function on), or more specifically, the torque converter clutch (TCC) slipping at highway speeds.
The TCC locks the torque converter once you're cruising, reducing internal slip and improving fuel economy. When it starts failing, you get that feeling of no real power until the revs climb. The gearbox feels like it's half-engaged. Fluid starts to overheat from the constant friction.
This is a clutch wear problem. The friction material on the TCC wears down over time, especially if fluid hasn't been changed on schedule or the vehicle has done serious towing.
The Burnt Smell Is a Red Flag
Normal ATF is pink or red and smells vaguely sweet. Burnt fluid is dark brown or black and smells like scorched oil.
That smell means the fluid has been overheating, the additives have broken down, and clutch material is breaking apart inside the gearbox. Once that debris is circulating, it accelerates wear on everything: solenoids, valve body, remaining clutch packs.
Don't do a full flush if the box is already slipping. Flushing a worn gearbox can dislodge debris that's been acting as a makeshift seal, causing an immediate total failure. Drop the pan instead, replace the filter, and do a partial refill. That's a much safer approach when things are already marginal.
Why Are the Shifts Slow and Sluggish?
A few things cause this on the RE4R01A and RE4R03A.
Low fluid pressure. The valve body and governor regulate pressure throughout the gearbox. As these wear, pressure drops. Clutch packs don't engage as firmly or as quickly, so shifts feel lazy and incomplete.
Solenoid problems. Dirty fluid gums up the shift solenoids that control timing. They can sometimes be cleaned, but usually need replacing once they've been sitting in degraded fluid.
Clutch pack wear. Less friction material means less grip. The gearbox still tries to shift, but the clutch slips before fully locking in.
Throttle position sensor (TPS). The transmission uses TPS input to calculate shift points. A faulty TPS can produce erratic or lazy shifting that looks exactly like a gearbox problem. Check this before assuming the worst. A new TPS is $50-120 AUD ($30-75 USD) and takes 20 minutes to swap.
Can It Be Fixed Without a Full Rebuild?
If you catch it early, yes. If the fluid isn't fully burnt and the gearbox is still engaging all gears, a service, fresh fluid, and a valve body clean or rebuild might get you another 50,000 km.
If the fluid is black and the slipping has been happening for a while, a full rebuild is usually the right call. Half-measures on a box this far gone rarely last.
A rebuild on the RE4R01A or RE4R03A by a Patrol-experienced gearbox shop in Australia runs approximately $2,500-4,000 AUD ($1,600-2,600 USD). That covers new clutch packs, seals, a rebuilt or replaced torque converter, and a valve body overhaul. Some shops will supply and fit a reconditioned exchange unit for a similar price.
In the US, reconditioned RE4R03A units for imported Patrols can be sourced from specialty suppliers for around $1,800-2,800 USD ($2,800-4,300 AUD).
A fluid and filter service with a pan drop: $200-350 AUD ($130-225 USD).
How to Keep Yours Alive Longer
If your Patrol auto is still shifting cleanly, the best thing you can do is keep it that way.
Change the fluid every 40,000 km on normal driving. Drop that to 20,000-25,000 km if you're towing, going offroad, or driving in consistently hot weather. The heat is what kills these boxes.
Use the correct fluid. Both the RE4R01A and RE4R03A call for Dexron III or a compatible modern equivalent. The wrong fluid will destroy shift quality fast.
Fit an external transmission cooler if you haven't already. The factory cooler built into the radiator is minimal for a vehicle this size. A quality external cooler costs $100-250 AUD ($65-160 USD) fitted and can add significant life to the gearbox, especially if you're doing any towing or serious offroad work.
Should You Buy a Patrol With These Symptoms?
Only if the price reflects the gearbox work required. Budget a minimum of $2,500-3,000 AUD for a rebuild and negotiate accordingly. If the seller insists the box just "needs a service," walk away or get it inspected by a specialist first.
A Patrol with a healthy gearbox is genuinely worth having. One with a tired box that's been ignored is a money pit until the transmission is sorted. Try TorqueBot Free | Download on iOS | Get it on Android