ford 8.8 axle differences 95-98 F150

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Jun 15, 2003
All right gents.

Have a 95 F150 300-6 5 speed 2wd with a whiny (esp at 45 mph) rear axle that ate a pinion seal and has slop in the pinion entrance. Figure the pinion bearing's gone bad and the gears have been clashing wrong for a while.

I'm not smart enough to set up a new ring&pinion so I just picked up another 8.8 inch axle from a 98 4.2 V6 and am trying to make sense of things. Seems they changed some stuff:

The lug circle is slightly smaller. Glad I didn't get it all built before discovering this.

The wheel cylinders are bigger... 1" vs 15/16" or something. Need new cylinders as the old bleeders are going to snap.

Brake shoes are different part #s. What did they do different?

Will also need an axle seal as the new axle puked gear oil all over the driver's brake.

On to the questions!

It looks like I at least have 31 splines in common, so I was going to take my old axle shafts and stuff them in the new housing. Watched a youtube on pulling c-clips, looks like something I can do.

What's up with the brakes changes? I understand the drums are different part #s because of the lug holes. I'll keep my old drums to go with my old axle shafts and lug pattern (and wheels and tires!!!) But what of the shoes and cylinders? I also need a hardware kit as I cut the backside of my nails to get a frozen drum off. Should I just switch backing plates to unite all my braking problems under one year?

I also have to do an axle seal but figure this should be cake. Also, fun, have to move the e-brake cable over as my "new" one got roasted on the exhaust. And completely replumb the brake lines.

Anything else that's gonna get me? I'm trying to keep the axle case with its good diff gears because "a wizard did it".

PS going from 2.73 to 3.08 which pleases me, and I can reprogram the speedo to match.
To answer your questions:
I don't know, I don't know & I don't know.

This reminds me of when my Brother bought a new refrigerator and then found out it was to "tall" to fit under the cabinets.

I routed out the trim and we were able to squeeze it in.
Would have been easier if he just bought the correct size in the first place.

Good luck. I'm sure others here will offer good advise.
Ford infuriates me with their nonsensical changes. I would turn the 98 rear end into a 95 best as you can. Please post follow ups. Hard ware kits are cheap and available at any auto parts store.Sounds like you have the 10" rear brakes. I advise replacing every hard line due to age and your location.
A broken line on the Rat led to the most extensive brake job Ive ever done to a single vehicle. The MC and a rear hose are original, the rest is new. Parts are cheap and readily available.
I don't think there's much you can use there, except maybe the guts of the diff. I'm not even sure that will work. The F-150 underwent a complete ground-up redesign in 97, so the 98 that the axle came out of is a completely different truck than your 95. IIRC, the 98 axle is longer, so the spring perches won't line up with your springs, and your 95 axle shafts probably won't work in the 98 axle. The 97+ brakes are larger to accommodate higher payload and towing capacities, and anything smaller than a 16" wheel won't fit over them.
^^This. You have two axles from two different generation trucks. The drums might be two different diameters, which would make shoes and wheel cylinders all different too.

If your truck has a speed sensor on the rear end, you don't need to reprogram the speedometer even if you change gear ratios. The only time you would need to reprogram it is if you change tire sizes. The tone ring that gives the signal to the sensor is on the ring gear and turns the same number of revolutions no matter the ratio.
Also, on your 95, the speedometer/rear ABS sensor is located on top of the diff. Look to see if the new axle has this sensor, I don't think they do.
It is absolutely not cost effective for you to try and make the 1998 housing fit your 1995. The perches and shock mounts will need relocation as well as dealing with the brake and tone ring differences.

I recommend either replacing the ring and pinion in your existing housing or acquiring the correct generation axle for your truck.
Yeah, it's 47 inches between springs on my truck and 49 on the new axle.

Gonna dump it and just turn up the radio.
The 8.8 in my Bronco has been howling loudly for years (since before I bought it). I'm getting it rebuilt in the spring, and re-gearing it to 4.10s (it has 3.55s now). I already bought a used front axle with 4.10s and had it freshened up with new bearings and seals.
As has been pointed out, the F150 changed completely between the '96 and '97 model year. That is why you've found all sorts of differences between what you had and what you bought. While the internals of the 8.8 are likely the same, the external stuff (spring mounts, shock locations, brakes, axle shaft lengths, etc...) and some physical external dimenisons are all likely different.

Not exactly a non-sensical change in this case. Just a different application.

Best bet is to dump it and buy an axle from the correct generation of F150 or just rebuild what you've got. Based on recent pricing I've seen in local yards, I'd pay for the rebuild. (And that's what I plan to do on '04 F150 with a 9.75 that howls around 50 mph).
Yep..completely different truck...ring/pinion/diff is about only thing ur gonna be able to use...that means setting up the gears correctly back into the old housing/ setting pinion depth, preload and backlash....its a black art and only a few know how to do it right....good luck.
If I could find an axle wizard to use my gear set I'd still be ahead as I only paid $70 for the whole axle, which is less than a gear kit.

I only drive it 1k a year for chores & errands, though it's a very nice truck, rust free and rare for that up here. Sounds like I have years to go at this rate though. Maybe having replacement parts on hand will keep the demons at bay, knock on wood.
You can get a new ring and pinion for the 8.8 for cheap from FRPP. Setting one up isn't difficult really, just follow the instructions. Plus while you have it apart you can weld the tubes to strengthen the assembly.
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