rossibaby

I have a 2005 F150 STX with 4.2 6 cyl, automatic.
an accident bent the rear end and I need to replace the whole assembly.
My truck currently has a 3.73 gear ratio with 8.8 ring gear.
All the used replacements I am finding are priced between 1100 and 1300 and rebuilt units are 3 grand.
I have found a 3.55, 8.8 and they are much more reasonable.
If I replace my 3.73 with this 3.55 assembly, what issues am I creating?


I use this truck as a commuter with occasional very light hauling, no towing.
Can I do this and simply have the computer updated?

redranger04g

Better highway mileage, worse city mileage, less power off the line and less towing power. But none of that is going to be substantial. If you can save a good amount of money I would do it.

rossibaby

Thank you, redranger.
One other thought.
Can I replace the 3.55 gears with 3.73 in the new unit, without too much trouble, or am I opening up a can of worms?

redranger04g

Yes it can be replaced no problem. It is expensive though, swapping gears usually costs between $800-1000 (ballpark) so you are right back in that original price range that you posted. You might save a little money.

rossibaby

Thanks, Man,
I'm thinking that I have a 3.55 in my future!

rossibaby

Rear end swap is complete.
3.55 rear end is installed.
No issues at all.
Didn't not even have to reset the computer.
I've put about 300 mile on since the change.
Running fine.
Thanks again.