Greetings,

I drove home a new to me, 1986 F250 4x4 manual tranny truck awhile back and noticed that the drive drive train would "Grab" occasionally...similar to a wrench being tossed into and between turning gears. Unfortunately, It didn't do this during the test drive prior to the purchase. I should have done a longer test drive I guess. Caveat Emptor, as they say.

Anyhow, the truck didn't cost much, so... I just need to fix it. It felt/sounded like the rear diff. was where the problem was, so I removed the diff. cover to find very grungy gear oil, a large metal washer type part laying around on the loose and lots of metal particles.

So, what should I do now ? Rebuild or Replace ? How do I determine what ratio I have ?
I think the unit is a Sterling 10.25 full floating axle. Has anyone rebuilt one of these before ? All useful suggestions appreciated. Thanks.

 

Sterling 10.25 axles are the more 'modern' type under 3/4 and 1-ton Fords, from, well, 1986 until at least '02 or so, with minor differences.

They are pretty solid, and, having disassembled one myself, pretty easy to work on.

There isn't much to get them apart, and you can actually do this without removing the tires.

1. Remove the 8? bolts on the end of the axle on both sides. You can then lever off the end "cover", which is actually the axle shaft. Just pull them both out(Get a pan for dripping oil, though).
2. Remove the diff cover(as you already did).
3. There are 4 bolts holding the center section in. 2 on each side. Remove them, then get a bar in behind the center section and it should come out.
Watch for shims on both sides, and keep them organized. Check the "pockets" on each side to get out any shims that are still in the differential.
4. With the center section out, you can now remove the pinion. You need a big socket on the pinion nut, and you'll want a big pipe wrench to put on the driveline yoke to keep it from spinning. Pull the nut, and the yoke should just slide off.
The pinion will then slide "inward" and you can remove it easily.

You can then go over it, see what the problem is, and what actually need to be replaced.

Also, pictures are good.

Edit:
Unless the axle has been replaced or changed, just look at the VIN tag inside the driver's door. It'll have the axle code which you can look up.
Chances are, for a 1986, you have a 4-speed manual and 3.55 gearing.

 

Definitely need to tear down and inspect. Good excuse to swap to a long pinion gearset and yoke. The earlier 10.25" axles had short pinions which loosened up and wobbled as well as wearing down the splines. If caught early this can usually be remedied with a solid spacer instead of a crush sleeve, a crush sleeve eliminator kit for a 9" works if you radius the inside of the thick spacer that sits against the pinion. Use this regardless of whether you reuse your original gears or swap to a long pinion set.

 

I would check your wheel bearings before tearing into it.

I had the rear axle lock up randomly driving down the road a few times, it would lock up for a few feet, skid tires, free up and keep going like nothing happened.

2 days after, this happened, bearings were gone.

 

Brakes look good! /jk

 

Thanks for the good advice from everyone. I feel like I have some direction now.

Very good step by step by "Macrobb"... he could work for Chilton or Haynes !

I need to study this Long pinion, short pinion issue. A weak point apparently.

And...I also need to check my brakes and axle nut so I don't lose a wheel like "IDIDieselJohn" .

After I pull it apart, should I post back with some carnage pic's ? Later, Brad.

 

Rob knows too much to work for those guys!

 

I recommend getting a 8.8 crush sleeve eliminator from Jegs. It's the same size as what's used on the 10.25 and should eliminate yoke walk and excessive amount of money spent converting to a long pinion.

 

Thanks for the tip. A spacer and shims kit rather than a crush sleeve...seems like a good idea.

 

Good point.
I just looked up what I used:
Carrier shim set(if replacing gears or something): http://www.ebay.com/itm/YUKON-FORD-10-25-Super-Carrier-Shim-Kit-FREE-PRIORITY-SHIPPING-/171874707769?hash=item280487e939 - $28.60

Pinion spacer (crush sleeve delete): http://www.ebay.com/itm/Ratech-4105-Pinion-Bearing-Spacer-9-8-8-7-5-10-25-10-5-Ford-Solid-W-Shims-/171600248898?hash=item27f42c0042 - $19

I never had any trouble, so I guess it worked.

 

Pic's of the axle innards.