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Hey guys, few questions regarding auto transmission compatibility for a possible swap here in Australia.
Pretty sure most you USA folk wont be too familiar with the Nissan Patrol(GU) however have one with an RE4 auto that I was hoping to retain to make the conversion simpler. Not tails shaft mods, mounts etc etc.
Adapters for auto to cummins are available so no probs there, just wondering if the gear ratios will work with the 4bt? The ratios in the box with a little description I got from a very reputable auto trans mob over here. See below. Currently have 4.6 diff ratios, but can change to 3.9/4.1/4.3 if needed. Hoping I can get away with the factory TCU and won't need a stand alone computer for shift patterns.

Nissan RE4 4 Speed
The Nissan RE4 transmission with the larger torque converter, available since 09/1992 in the GQ Patrol, is one of the most mechanically reliable transmissions we have seen and is perfect for a Towing and Touring vehicle. Can be used with the factory T-Bar shifter or any aftermarket shifter that has an overdrive button.

Gear Ratios for Nissan RE4 4 Speed
First Gear​
Second Gear​
Third Gear​
Fourth Gear​
Reverse Gear​
2.785​
1.545​
1.000​
0.694​
2.275​
 

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Maybe one of the guys like Dougal who's closer to you will have some ideas. If this is going to be primarily a road vehicle, I'd think a little higher differential gear ration like the 3.90 might be better. The 4bt peak torque is usually in the 1700-1800 RPM area. They like to run in the 1600-2000 RPM range for best fuel economy. You'll need a torque converter with a stall speed designed for a diesel. Most guys here shoot for around 1300 RPM. If that transmission is computer controlled, then you may need an outboard controller. Don't know how strong that transmission is. A 4bt is a torque monster. With a bit of tuning the engine can have 200 HP and around 450 lb ft of torque.
 
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