2003 5.4L - Transmission cooler + other upgrades for towing?

Eric M · Apr 23, 2021

Never having towed anything greater than a 4x8 utility trailer, I wanted to make sure I had all my bases covered before towing a travel trailer (3000-3500 lbs.) with my 2003 expy.

I have the 4R70W transmission. I'm guessing a transmission cooler would be a good idea? If so, any recommendations?

Also, are there other towing related add-ons that I should consider?

Thanks!

Aspen03 · Apr 23, 2021

Does your 03 have the HD tow package? If so, it'll already be equipped with a cooler.

Eric M · Apr 23, 2021

Thanks for the info. It is an Eddie Bauer and has a factory tow package with all of the electrical hook ups. I guess that is the HD package?

Aspen03 · Apr 23, 2021

If it has HD tow you'll see the 7 pin round connector just above the 4 pin, should also be able to locate the transmission cooler pretty easily as well.

Hamfisted · Apr 23, 2021

Do you know if the travel trailer has brakes on it ? Make sure your Expy brakes are in good shape as well.

If the trailer has electric master cylinder brakes, you can add a brake controller to the Expy very easy. The brake controller plug is right there by the OBDII port under the driver's dash, about where your right knee would be. It's plug in play with most Hayes, or other aftermarket controllers.

Brake controller plug by OBDII port....

Hayes brake controller installed ....

David E · Apr 24, 2021

Mine came with the 4 pin connector and a "regular" size tranny cooler. I upgraded the cooler to a larger one (I believe the one comes in the HD package) and plan to install the 7 pin along with the brake controller for my 3200lbs camper. Was also planning to upgrade the radiator to the bigger one but I believe that would require new pipes (bit of a deterrent) so might not do that.
To my best understanding the wiring is mostly there just a bit or work and it should be done. (did the same for my Minivan which had no setup at all and was a lot more complicated.)

Eric M · Apr 24, 2021

Aspen03 said:
If it has HD tow you'll see the 7 pin round connector just above the 4 pin, should also be able to locate the transmission cooler pretty easily as well.

Got it. Thanks again!

Eric M · Apr 24, 2021

Hamfisted said:
Do you know if the travel trailer has brakes on it ? Make sure your Expy brakes are in good shape as well.

Will do. Thanks!

Eric M · Apr 24, 2021

David E said:
Mine came with the 4 pin connector and a "regular" size tranny cooler. I upgraded the cooler to a larger one (I believe the one comes in the HD package) and plan to install the 7 pin along with the brake controller for my 3200lbs camper. Was also planning to upgrade the radiator to the bigger one but I believe that would require new pipes (bit of a deterrent) so might not do that.
To my best understanding the wiring is mostly there just a bit or work and it should be done. (did the same for my Minivan which had no setup at all and was a lot more complicated.)

Very helpful. Much appreciated.

BlackCoffee · Apr 26, 2021

The 2003 Eddie Bauer has a connector just above the gas pedal to hook up a brake controller. My EB Bauer came with the Towing Package so the 7 pin connector at the hitch was installed. As for the connectors, I am not sure, but I would think they are part of your harness. I don't think they had different harnesses, just the connector and transmission cooler.

2003 5.4L - Transmission cooler + other upgrades for towing?

Eric M

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