Fitting an external Transmision Fluid Cooler

on Friday 23 November 2007
in A-Z Index - Everthing is listed in here > Transmission

This should be a mandatory mod for ALL auto-Zeds, TT & NA alike due to harsh summer ambient operating temperatures.
The good news: it's relatively cheap and easy to install.

Q: "Why install aftermarket? My Zed already has a cooler built-in to the radiator"

A: The radiator performs a reasonable job of cooling transmission oil, although a separate aftermarket cooler not only does it better, it also reduces load on the engine cooling system.
Automatic transmissions typically run at up to 120 degrees in summer temps during high load driving situations; hill-climbing, towing, constant shifting etc., and may also absorb radiated heat from exhaust systems and the road itself during stop-start driving.
Transmission fluid (oil) is not only the driving force in the Torque Converter, or 'clutch', but also lubricates all moving parts.
High temperature operation reduces the oil's ability to protect the major components: clutch packs, planetary gears etc., and leads to premature failure.

Selecting a cooler:
Buy a known brand-name cooler such as PWR, a greater surface area is preferable to a thick core.
I purchased a PWR cooler measuring approx. 280mm x 280mm, that would easily fit below the air-intake Y-piece, behind the pod filter, in the nose section.

In the pic above, you can see the new cooler installed snugly between engine oil cooler (centre left) and below the Y-piece air intake.

To fit, it was necessary to spin the OEM engine oil cooler 180 degrees, re-using the center retaining bolt only, & re-plumb the hoses.

I installed the new cooler with top and bottom support brackets bent out of alum. bar & drilled for fixtures.

Position cooler with inlet/outlet on drivers side, allowing oil to rise from the inlet to the top, outlet.

Whilst you may connect the cooler yourself by disconnecting existing lines which run to the radiator, it is prudent to have this minor task done by a Transmission Specialist during a service & oil change to avoid contamination.
It's also much easier to connect hoses whilst car is on a hoist.

Note: Front bar removal is not required, just nose panel.

Additional pics here (Click pics to go to enlarged versions):


Supplement by SIM300:

Oil hoses to engine oil cooler can be difficult to remove. Pouring warm/hot water over them will expand hoses and make it a lot easy to pull them off. After rotating OEM engine oil cooler 180 degrees you will notice that one of the hoses will need to loop back around as seen in pic below. Be sure the bend in the hose is large enough to allow oil to flow easily.

I mounted the trans cooler from the bottom using the same method as K-zed. But differently, I secured the top by bolting it to the thermo fan support (edit: this particular method requires the use of a small cordless or 90 deg drill chuck or alternatively front bar removal to allow space to use a normal size drill). Also, I mounted my cooler so that the inlet/outlet hoses are attached from the bottom.

Below pic courtesy of SIM300

(Note: Front bar removal is not required, just nose panel.)

Cheers, K-Zed