Axle & Gears

[Renegades8]

Do you have to change gears if you buy new axles

 

[Tiha]

You don't have to.
You can buy axles with the correct or your desired gear ratio unless you are running something really unique.

Are you looking for standard replacement?
What are you working on?

 

[Renegades8]

You don't have to.
You can buy axles with the correct or your desired gear ratio unless you are running something really unique.

Are you looking for standard replacement?
What are you working on?

It’s 1988 Bronco I am seeing some unusual wear on the spline on drivers side. My intent is to put new inner and outer bearings front and rear clean up under carriage and paint. Putting on 6” lift kit 18” rims 35x12.5 tires interior has new racing bucket seats diamond tuck interior bought a plastic mold headliner with speaker system built in neon head light rear tail light lens dark windows tinted having the truck repainted pearl white with rolling ghost flames did some small motor work so far has a 351 Windsor so far performance chip air intake changed looking at turbocharged. Body is in perfect condition. Gentlemen bought it passed away and sat in garage for years. That’s my story. Back to axles I am looking at a new set 9” factory spec after market.

 

[Tiha]

Your current axle will have a tag on it telling you what ratio it is.

There are other options to find out as well. If it is original the door sticker will tell you. But going with 35's are you thinking of changing it?
Then you would have to change the front too.

 

[paul rondelli]

I'm running 4:56 gears with a 6 inch lift and 35" BFG mud terrains in my 1993 5.8l E4OD Bronco. Really increases the seat of the paints acceleration …… almost worth the decrease in MPG. When you get less than 10 mpg you are just a glutton for punishment. That is why the lifted Bronco looks badass parked at the house... while I daily drive the 1996 Bronco with a 5.0l and a 5 speed. I can almost get 17mpg with the stock gears.

 

[chrlsful]

never trust tags, stickers, grease pencil, etc to assess a "new-to-me" axel ratio. Mark the DS & count the tire rotations. This way U know what U have.

Spline wear could mean bent axel/diff housing instead of th above.

 

[Jasgeer]

It’s 1988 Bronco I am seeing some unusual wear on the spline on drivers side. My intent is to put new inner and outer bearings front and rear clean up under carriage and paint. Putting on 6” lift kit 18” rims 35x12.5 tires interior has new racing bucket seats diamond tuck interior bought a plastic mold headliner with speaker system built in neon head light rear tail light lens dark windows tinted having the truck repainted pearl white with rolling ghost flames did some small motor work so far has a 351 Windsor so far performance chip air intake changed looking at turbocharged. Body is in perfect condition. Gentlemen bought it passed away and sat in garage for years. That’s my story. Back to axles I am looking at a new set 9” factory spec after market.

Sounds sweet!
The Achilles heel of the 8.8 inch Ford axle is the number of splines on the axle shafts. By year yours should be 31 spline which is considered adequate for the original sized tires (NOT 35 INCH MONSTER TIRES). If you are seeing a strange wear pattern on one of the splines then I suggest you need to further investigate it. Axle shafts are available with 33, 35 splines and sometimes even higher. Brands include Moser, Strange, Nitro and many others. More splines means that the diameter of the spline is larger and stronger. I know of many higher performance 4x4 rigs running 33 or 35 spline axles. Higher performance axles can also be made from stronger steels than the original Ford OEM axles.
JUST MY 2 CENTS!
I should add that if you saw abnormal wear on the axle spline that it also probably means the the spline on the inside of the differential gears may be equally worn.