Towing Difference Between 3.55 and 3.73 gears | Page 2 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Towing Difference Between 3.55 and 3.73 gears

Follow up questions to this thread.

As this hasn't been posted to in a while I'm not sure if someone will respond but here goes. New to this forum and have an 05 Explorer Limited with the 4.6L V8 and an automatic tranny. It is the 4x4 model. I have a couple of questions I could use help with. Explorer has almost 200,000 miles on it. Original motor and tranny. Well maintained.

1. I have a Class II hitch on my Explorer so I assume I only have the 3.55 rear axle ratio, not the 3.73. Does anyone know how to confirm this?

2. I am buying a 24' deck boat which, with trailer, will be about 5,000 lbs. Does anyone have an opinion as to whether I'd fry my tranny if I simply replaced my Class II hitch with a Class III hitch without swapping out the rear diff?

3. If I need to go all the way in order to tow this kind of weight is there anything I need to do other than a) Swap to a 3.73 rear diff, b) swap to an OEM class III hitch and c) swap the power/light connector out if needed?

Should I make sure I have trailer brakes.

Love my Explorer but I'm worried about putting $500 - $1,000 to swap everything and then blowing the tranny or something else.

Any input would be appreciated.

Rob
 






With the class II hitch your vehicle was rated for 3,400 lbs, with the tow package, it was rated for 7,000. The tow package had the 3.73 rear-end and a Class iii/iv hitch, along with the wiring harness for a 7 pin connector.

There is not much difference between the 3.55 and the 3.73 rear end as far as RPM/ torque, so you would probably be OK. The Class II hitch is what limits you to 3,4000lbs.

The real question is do you trust your Transmission to be up to the task with that high mileage? I have a 2003 V8 with the tow package and a 5,500lb trailer I have pulled for the scouts is a significant load. Ok over flat lands, but a lot a gearing down to get over the Appalachian mountains.
 






Another member posted this a while back. Plug your VIN into it under the "Vehicle" tab and hit the drop down arrow on the far right side about mid-screen. It'll tell you all about your Ex.

http://www.etis.ford.com/vehicleRegSelector.do

I would be more worried about whether you had the appropriate coolers (engine oil, trans, etc.) than what axle ratio you're running.

I would also double check your boat/trailer weight. 5k lbs seems light for a 24' deckboat. Remember to add weight of gear, coolers and fuel. Our 21' bowrider tugs at about 5700lbs fully loaded.
 






Thanks to all for the responses. It helped med decide to sell my beloved Explorer and buy a truck or larger SUV that's already set up to tow a sizable boat.

Rob
 






Back
Top