burtgtp1973

Hello First Post. here!
I'm picking up a 2010 F150 XLT 5.4 tomorrow, and the issue is, there is some noise coming from the rear diff. The owner says it only happens when turning while going forward under power. I have no knowledge of these trucks and I'm just looking for a starting point. Is there a known issue with diffs specifically? Any other issues I should look for when checking out the truck?

I appreciate any help!

TIA!

montanaman

Is it a Trac Loc? What's the axle code off of the door jamb?

BareBonesXL

Screech, howl, click, clunk, tap-tap-tap, aaaoooooogaaa! ?

burtgtp1973

Im unsure as I haven't bought it yet. I'm meeting in the morning to pick it up. What can you tell me about the Trac Loc? Is it common, is it hard to fix/replace?

291433

if it happens under load that tell me almost instantly that there is a bearing wearing down and is fine just rolling but any stress applied and it starts to whine. if your dead set on this truck i would ask them to take some off the price for a rear end rebuild because thats probably what it needs.

burtgtp1973

What does a rebuild build consist of? Is it something a seasoned mechanic can do in a afternoon?

BareBonesXL

You're spending a lot of thought on "some noise coming from the rear diff". Could be a stick stuck in the drive shaft.

burtgtp1973

Lol! This is what the seller is said about the issue.

Bad- Rust starting in cab corners, damage to drivers door, rear diff making noise when turning (limited slip?), small tear in side of drivers seat (not shown)

followed up by: As noted in the post, the rear end is making noise. At this point it only happens when turning, going forward, under-power. It is either limited slip fluid is losing lubrication and needs changed, or ring and pinion are wearing out. I’m leaning more to ring/pinion because of miles and that they have not been replaced to my knowledge.

Lets assume the owner is right: my question is; what does it take to fix?

Thanks again for the replies.

burtgtp1973

It's a pretty good looking truck!

BareBonesXL

It's probably not what you're thinking ("losing lubrication and needs changed" is not really a thing, and ring and pinion gears usually last a long time) but diff work is not too expensive.

Good luck. Only posted 'cause I thought you might be able to describe the noise or have some better info, like chunks of metal in the diff. Without that it's just a bunch of wild guesses.