I picked up an old F250LD that had been parked for a while this past weekend. Working on bringing it to life as a tough beater. It rumbles above 30mph or so and gets worse when turning right and less when turning left. I put the rear on stands and put it in gear and noise seems to be coming from driver side. When messing with them by hand there's some play in both sides and more noise on left side. I'm feeling like the right next step is to do bearings and seals especially on the left side. Probably both.

Now these trucks are weird as anything and anyone who can possibly help me will know what I mean. The tag on the differential seems to me to be telling me that it's a Sterling 10.25. However the axles look absolutely nothing like the Sterling 10.25 and look very much like the Sterling 9.75 instead.

I assume I should be looking at seals and bearings for the 9.75 rear and any differential parts for the 10.25? And if I want to watch a video tutorial then I should use an F150 video for axle removal and an F250 video for pinion shaft? I'm completely inexperienced in tearing apart rear ends but feel fairly confident I can do the axle seals and bearings. When I popped open the fill plug on the differential the level was good but there was a fair amount of metallic gunk on the magnet. Not sure if that means I should be thinking about also doing some bearings in there while I've got it open? If I did want to do bearings in the differential what is the chances that I'm gonna end up wtih a lap full of parts that I can't get back together? I've done suspension work, normal maintenance like brakes, but I've never messed with something like this. I didn't pay much for the truck but my wife was against me buying it at all and if it's out of service too long she's not gonna be impressed.

Thanks for any advice.

Here's a couple pictures to show what I mean about the differential and rear axles. https://imgur.com/gallery/8zmiTye

 

Someone has had the cover off by the looks of the red seal material pushed out from the cover.
You have to take the cover off and look at the condition of the ring gear and pinion as a start.
If they are worn to excess, you may as well look for a good replacement rear and save your self all the hassle.
Setting up gears and differential bearings is not for the first timer.
And yes, axle bearings might be an issue for part number on these rears and depends on what Ford did with the housing ends.
Better to see what all you have to contend with, first.
Some advice about the peanut gallery; you half the show, do what you have to do.
She will get over it.
Good luck.

 

Thanks for replying back. I think I have been over thinking it probably. Since the axles look just like the 9.75s it should be pretty much the same procedure to get them out. No bolts on the outside, so they must be c clipped.

I'm not gonna worry about the differential as if that goes the truck will probably go with it. I'll mop it out and it'll have fresh oil and that's about the best I can do. I found on this forum a really good walkthrough with pictures for pulling the axles on a 9.75 and I'm feeling good about it.

After I get the seals & bearings out I'll bring them in with me and we can compare side by side with the bearings for the 9.75 and the 10.25 and hopefully will be able to see the difference of which one I need.

The truck has 292k on the odometer and I know it's on it's 2nd engine. I bought it about 50 miles ago so I'm just putting out the biggest fires so I can dump some real miles on it and see if it's worth keeping around to haul wood. And someone is always moving and it would be a great truck to not worry about getting dinged up. The body and interior are in surprising shape for the miles. There's a decent amount of rust on the frame but it's all so heavy duty that I don't have any doubts about the integrity. Talking about that, do you have any advice on whether I should wire brush everything and get that rust off? Or will that make it rust faster? And if I do brush it should I spray something on? I've read horror stories about undercoating but idk if there's anything that is a good idea or I should just leave it as is. Just would be a decent time to do it when I'm screwing around underneath anyway.

Thanks

 

good idea to leave the pumpkin alone and work on the axle bearings....

chip off the heavy rust on frame and wire brush a little... wipe it down and get some RUST CONVERTER and spray or paint on... make sure it is a CONVERTER and not a paint.. Converter does a chemical reaction with the rust and turns it into a HARD BLACK OXIDE surface..... you can then paint over that or spray undercoating.

 

something like this... looks like milk and turns the metal BLACK... paint it on, or put in a spray can... I did axles , frame, springs, brake lines, EVERYTHING that has rust on it.

https://www.ebay.com/itm/Rust-Conver...UAAMXQWzNSn4rS

 

Hi back again. Wheel bearings went fine, found the correct parts easily by having the parts store search by vin # which is a really cool thing I wish they would add to their websites.
However it didn't actually fix my problem which I'm now convinced is the differential carrier bearing.

I know everyone says differentials aren't for first timers but I guess I don't really see how anyone would ever learn to mess with differentials then since first time has to come sometime. So my plan is to do just the carrier bearings and not touch the pinion at all which as far as I can tell should make things 100 times easier since I should just need to dial in backlash only.
I'm planning on buying the yukon kit which comes with their 'super shim' kit which people online seem to like. My question is should I put the stock shims back in and measure or should I mic the stock shims and put same thickness of new shims? I'm pretty sure I should use the stock shims because if the bearings are the same thickness then I should be on the nuts immediately, right? Keeping all the same gears, new carrier bearings shouldn't mess with anything assuming the bearings are the same which I realize they might or probably won't be.

My next question is about backlash, how important is it to be exactly the same as before? Assuming it's in spec to begin with do I need to get it exactly the same or is it good enough to be still in spec (6-10)? Like if it's 0.09 and after I'm done it's 0.06 for example will that cause a problem?

Overall I feel pretty confident that this shouldn't be too terribly difficult as I'm not rebuilding the whole thing and setting backlash seems a lot easier than setting pinion depth & backlash together. Btw if anyone is interested my plan is to bring the whole ring gear and all to a shop and have them split & press the bearings for me. Hopefully someone will be willing to do that for a little cash.

Open to tips and warnings

 

Providing the ring gear and pinion are not worn through their hard surfacing into soft cast iron, not having the back lash proper will either cause a Hum under power or in coast besides a clunk on and off the throttle from excess clearance.. Of course the clearance should never be tight because under heat, it only get worse and does damage..
It has to be correct.
If new gears are installed, there is a break-in period and procedure to observe.
A Dial indicator, micrometer might be needed, and marking white paint is needed to see the contact area between the pinion and ring gear.
This contact patch is affected by both the pinion depth, and side clearance position of the ring gear..
Find the information for working on this rear and study it until you understand what has to be done and tools needed..
There are no short cuts to this.
Good luck.

 

all bearings should be made within .001 inch so changing out the bearings and using the same shim pack should get you REAL CLOSE.. There may be some wear in the pinion / bevel gear, so check the backlash and verify it is correct.. ALso the shims set the preload on the bearings so that needs to be checked also.. no pinion work... If the preload on the bearings is correct, and you want to get the backlash more or less... then move one bearing shim from one side to the other.. preload stays the same, and backlash is adjusted.