3.55 to 3.73 rear end swap in a 2002 V8 Eddie Bauer

[upei93]

I'm wondering if it is possible/worth it to swap my 3.55 rear end to a 3.73 so I can tow a 21 foot ultra light travel trailer. Can you just pull the gears and replace or does the whole rear end have to be changed?

 

[thebrakeman]

It would basically be done like an axle rebuilt. Go to a trusted axle shop (or the stealership), and ask them about it. They drain the fluid, open the case, pull out the gearing, clean the innerds, insert new gearing, seal, refill with new fluid.

If the truck is 4WD or AWD, both axles need the treatment.

Are you plannin to keep this truck much longer? If not, definitely worth considering finding an '09 or '10 Explorer. More power, better gas mileage, and full tow capacity with the 3.55 gearing due to the 6-speed auto.

 

[Ronin8002]

You can find a used 3.73 differential and swap that in place of your 3.55 rear end. Might be cheaper than paying to regear it from 3.55

I assume your truck is 2wd; if it's 4WD then you need to swap in a 3.73 front differential as well.