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

[Frank Swygert]

A 3500# trailer won't hurt a standard Expedition. A 4.6L standard model (not HD towing equipped) is rated at 5000#. The 5.4L is rated at more. You will need to add a brake controller and 7 pin trailer connector, but that's not hard to do. Will require running a couple power wires from the battery, one for controller, one for trailer connector.

My 06 with the HD package is rated to tow 8200# (4x4 -- 8400# RWD models). Now that isn't the weight of the trailer, but the trailer AND any load in the trailer and vehicle. My wife and I combined are 370-380, 45 for the dog. So that takes 415-425 off right away. 100# or so of luggage, down to 7600-7700. Another 300-400# of stuff in camper, so I'm maxed out 7200# for the trailer... and I have a 7200# trailer! It tows it ok. Just went to the mountains in NC (from mid SC) for the first time. Up the Saluda grade on I-40 it dropped down to about 45 mph up the hill, but stayed in 3rd gear. Coming out of Franklin NC it dropped down to 35 mph pulling up a very long 6% grade (a couple miles!). That was the longest and steepest hill. On shorter grades it only dropped to about 50 mph. If I were routinely traveling in the mountains I'd want more truck or less camper, but once a year at most I'm fine. I may upgrade the trans cooler though.

 

[BlackCoffee]

This might help you find the connectors on the harness. The brake controller is C2142 near where the ODBII connector is mounted. The 7-pin Trailer connector comes out of the harness next to the 4-pin and is C4099 .

 

[DLK726]

Would this brake connector diagram apply to a 2001 Expy?

 

[Hamfisted]

Would this brake connector diagram apply to a 2001 Expy?

Yes, look up under the dash near the OBDII port. Do you see the grey female plug there by it ? That's the brake controller plug.

 

[Grizguy]

If you only pulling 3500 pounds.. I don't think you will have any issue with any expy. Well.. maybe.. I had a 2005 expy with 250,000 plus miles. I bought it used in Florida with 150,000 miles.. I think pretty hard life. I drove it home to N W PA 80.. 85 MPH then with 225K + miles drove it to florida and back maybe a little faster than I should have More than 85... 90.. maybe a little faster.. Don't want to make people think I drive too fast.. After that trip, it did not like pulling a trailer any more. I was not pulling a trailer that fast..