2001-4R- Can this rusty diff and axle housing be saved?

[hawkcharmer]

Hello,

The rear differential and axle housing on this 2001 4R has some serious rust on it. Can this be saved? If so what's the quickest way to get this rust off and repaint? I will take it off the truck to do the work.

Any feedback is greatly appreciated. Thank you

 

[Hungryhawk]

Are the frame rails & cross supports as badly rusted? There is a lot of thick scale. I would get a stick welders chipping hammer. These hard steel hammers are designed with a clever grip handle that absorbs shock. Chip away and see if worst spots are superficial or deep. Getting those bolts out of the diff cover will take hours and hopefully not require tapping to a karger size. Deep corrosion cannot be welded, but once you find some shiny solid steel under the rust you can soak with rust lock products that turn rust into a stable grey material that paints well.

 

[T4R2014]

You need a sandblaster. Once blasted you'll find the pinholes and the brackets that were bound to snap off. Then you'll need a fabricator for all those minor things.

 

[hawkcharmer]

Are the frame rails & cross supports as badly rusted? There is a lot of thick scale. I would get a stick welders chipping hammer. These hard steel hammers are designed with a clever grip handle that absorbs shock. Chip away and see if worst spots are superficial or deep. Getting those bolts out of the diff cover will take hours and hopefully not require tapping to a karger size. Deep corrosion cannot be welded, but once you find some shiny solid steel under the rust you can soak with rust lock products that turn rust into a stable grey material that paints well.

Thank you very much! Frame is not as bad as the axel housing

 

[hawkcharmer]

You need a sandblaster. Once blasted you'll find the pinholes and the brackets that were bound to snap off. Then you'll need a fabricator for all those minor things.

Is there any specific sandblaster or material? Can blasting it do any further damage? what do you mean by pin holes and brackets? I should remove them prior to blasting yes?

 

[Hungryhawk]

Sand blasting or bead blasting that I have seen done makes a giant mess and the air around is contaminated with fine dust (unbreathable).
Operators usually wear a full suit with hood and inside a breathing mask usually attached to a breathing air source.
I cannot imagine a benefit unless you take body off frame and put frame into a shed/sealed room.

 

[NachesPass4x4]

I would replace the housing.

 

[BuffaloBass]

Thank you very much! Frame is not as bad as the axel housing

PLEASE CHECK THE FRAME CAREFULLY before you tackle the rear end. the worst i found was behind the gas tank, i put my fingers thru it! the welds on the forward control arm plates are where the rust started. Or came thru!

That rear does not look that bad, so the "replace the axle housing" advice is more than suspect. Bent, broke, maybe. Rusty and scaly - heck no.

A small hammer, a chisel, and most importantly, a needle scaler and compressor to run it will make short change of descaling that housing.

The needle scaler will find any weak points in the metal , if any.

Once its descaled you have a few options. For that level of rust, i;d opt for POR-15 basecoat, after a full water-based degreasing.Rust Prevention Products | Rust Stopping Products - POR-15

prep is key for any paints or resins ( POR is a resin) . For topcoat gloss will never look nice on a acned-up housing so matte nat gray, dark olive or black topcoat, whatever your preference.

FYI : https://www.harborfreight.com/air-needle-scaler-58645.html

Eye and EAR protection are key. The needler really "rings" on metal, so quite the racket. Neighbors wont like it. I was underneath working the frame and such, so a full face shield was required. Ear plugs for sure. ( and im a vet of close combat 'drills' )

 

[brillo_76]

All the members advice is great I would verify everything as most likely you have some frame pin holes as well. The back cover of the rear axle housing is a thin plate. Mostly once you clean it it make start to leak if the rusting is bad enough. They do make replacement dif covers that you can cut the old one off and weld a new cover on to save the axle housing. Check it out thoroughly as well as the top control arm brackets like to rust through and crack off. along with the spring perches and the lateral control arm bracket hole gets plugged and rots the top of that bracket right under the bolt out too from what I have seen over the years.

 

[T4R2014]

Is there any specific sandblaster or material? Can blasting it do any further damage? what do you mean by pin holes and brackets? I should remove them prior to blasting yes?

There might be a guy local to you who does blasting outside. See if they're willing to crawl under and blast the frame. The frame looks compromised. If not now then soon. Once you remove that scale it will be a lot thinner. The only fix will be a fabricator. I would find a good local one who can do this stuff. To actually get your frame looking good won't be possible without a lift and some mild fabrication at minimum.