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Jun 27, 2019

Nissan Skyline : Hot Shifter : Hot Transmission : Transfer Case Cooler


JDM Nissan Skyline GT-R - R32 for sale from importavehicle.com

Why does my shifter get so hot on my Nissan Skyline GT-R?
Why does my GT-R seem to bind up after a long drive?
Why do I smell hot ATF inside my Nissan Skyline?

In an all wheel drive Nissan Skyline, be it a R32, R33, or R34, the shifter goes into the transfer case or center differential.  The transfer case is the magic where part of the ATTESA all wheel drive happens. The rest comes from a pump, ecu, and a bunch of sensors.

The transfer case has a fairly small amount of fluid (1.8 liters, 1.9 quarts) in it, and that fluid can get hot when cruising on the freeway/highway . A difference in speed between the front and rear wheels, CAN,  create some heat in the clutch pack and transfer case. That difference can be something as simple as wear, tire pressure, or load.  Even with no pressure on the ATTESA control side, the theory is zero torque/force/dolphin power going to the front wheels.  Real life, and theories don't always align.

In some markets, they added a transfer case cooler to the cars.  This transfercase cooler helped to lower fluid temperatures with a pump, and a small cooler mounted under the car.   On the R34 race car, we had a transfer case cooler, transmission cooler, rear diff cooler, and had the provisions for a front differential cooler. See some pictures below for how those were mounted.

So how do you fix a hot transfer case on a Nissan Skyline GT-R?

  1. Make sure your wheels/tires are the same size, same wear, same height
  2. Don't drive long distances at high speed (yeah sure thing)
  3. Put a transfer case cooler on the car
  4. Ignore it (many people do)
A very important note is that the control side of the ATTESA system, and the fluid in the transfer case are separate systems. There is no commingling of the two fluids. Also the transmission itself, and the transfer case are separate systems.

Any binding felt, especially when turning is normally the transfer case clutch pack being slightly locked up.  This is why it is nice to have an open center differential or transfer case. When its open, everything can spin freely or independently.  This doesn't apply to cars with aftermarket front or rear differentials. Or even running some Shockproof Heavy in the rear,  which can make the rear differential lock up pretty hard. The OEM front differential is open.

The ATF in the transfer also splashes up onto the top shifter boot, and can deteriorate it over time. A split in this boot can normally be smelled in the car.  Nissan actually made a deflector to minimize this.  The OEM boot part number is:  32862-05U00

Transfer case cooler as installed on Australian market delivered R32 GT-R

Recommended fluid for the transfercase is Nissan Automatic Fluid Type D.


We normally run Redline High Temp ATF in the transfer cases. https://bobistheoilguy.com/forums/threads/nissan-matic-d-vs-dexron-iii.297783/


Internals of a Nissan Skyline GT-R transfer case


GT-R transfer case - Normal fill 1.8 liters, 1.9 quarts. 



Nissan Skyline GT-R transfer case clutch and chains
Transmission, transfercase, and rear end coolers on an R34 N1 Super Taikyu car
Transmission, transfercase, and rear end coolers on an R34 N1 Super Taikyu car

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Buy-R.com for Nissan Skyline GT-R and GT-R parts.




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