frank5079

On my way in to work this morning, I noticed a louder than normal whine coming from the rear end of my truck('95 F150 XLT). Working at a dealership, I had one of the techs I work with raise it on the lift to have a look see. Well his prognosis was grim and he showed me where the rear end had hemorrhaged gear oil all over the place. His advice to me was to find a replacement rear end because mine is dead.

After punching in my VIN on the VIN decoder, I found out that I have an 8.8 inch rear end with a 2.73 rear axle ratio.

Since I have to replace the rear end, can't I just use a good old 9 inch rear with a Traction Loc differential? What do you guys think?

fltdriver

There is a 95 with a 9" rear end/posi trac for sale locally, so yes you can.

sdmartin65

Depending on your area $150 to $350 buys a used 8.8 with most likely 3.55 gears. Going from 2.73 to 3.55 you'll wish that rear would have crapped a long time ago. I don't see the need for all the trouble of retrofitting a 9 inch.

Crownman

A louder than normal whine...... really?

Get another 8.8 and do a rebuild on it. And if you hear a whine fix it before you get to this point.

frank5079

Won't that hurt my mileage?? I get about 15mpg now....

sdmartin65

Come to think of it the vin decoder always comes back with 2.73, id bet you might have a 3.55 already. Drivers door jam has the axle code. Didn't catch the clue earlier, 2.73 is usually reserved for a 4.9, 5spd, xl.

broncojunkie

I second the notion of sticking with the 8.8. They are plenty strong enough. Everything eventually wears out (bearings, seals, etc) and they can fail quickly with no fluid in them...but the unit itself is capable of handling about anything you dish out...within reason, of course. If you're building an off-road beast of some sort or plan on racing, I'd consider some upgrades. But the 8.8 can even cover that, with some upgrades.

frank5079

That being the case, can't I just remove the open diff gears and replace it with an Auburn or Mosler LSD and slap it back on??

Crownman

What exactly did the tech say is wrong withe the rear axle? Because unless the physical housing assembly is messed up you can just rebuild it with new stuff.

Also, if you want to keep the highway gear ratio that you have now then dont bother spending the money for a built aftermarket diff. You can get a Ford Racing tlock diff assembly brand new for $240.

Brandon587

Just because you go with lower gears doesn't automatically mean your gonna take a hit in mpg. If the gears are too high (numerically low) it lugs the engine too much and makes it work in an rpm rang it doesn't like to work in, making it less efficient. How you use the truck, what engine, trans, and tire size are all key points when selecting gear ratios. But I feel personally 2.73 is too high even for a 4.9 highway cruiser.