The vehicle in question is a 1988 Ford Bronco. 351/C6. Yes I know this is not the Bronco forum, but they are so close to F-150s and this forum is a little more trafficked than the Bronco one. So play along if you'd like or get mad at me, either way I could use y'all's help.

1. On a 300 mile trip we "lost" a quart of oil. I say "lost" because I'm not sure how much is burning vs. how much is leaking. I know if you park the truck somewhere for longer than a few hours it'll leave its mark. Some is leaking from the drain hole, probably need a new crush washer or something, I don't wanna tighten it down too much and screw it up. The whole underside of the engine is a greasy mess, anyone know where these V8s have a tendency to leak oil from?
2. The t-case is super leaky too. The skid plate and bottom of the t-case are extremely ATF soaked. Not sure where its leaking from back here, should I just re-seal the whole case and if so how do I go about doing that? Also, pulled the fill plug and ATF came racing out. Odd since we haven't put any more in since we changed it. Do these things tend to pass fluid from the transmission to the t-case, and is that something I should be worried about? Transmission was full of ATF, last I checked (a week ago).
3. Here's the kicker. The rear axle is FUBAR'ed all up. The pinion is super wobbly and has play both side to side and up and down. The seal is shot, its leaking oil and the only reason it didn't leak before is because it was low on oil . The nut that holds it on is tight - must be the bearing. I have NO idea how to proceed with this - I've never messed with an axle farther than taking the cover off

Just need some guidance on how to proceed with these problems. I know a lot of the leg work will be checking for leaks and investigating, but I also know you all here can have some pretty good advice. Oh, and here's a bonus for ya, I've never had an OBD I vehicle, but is the CEL supposed to flash when the vehicle is in normal operation? It's not flashing like a major malfunction - instead acts like it's performing a self-test as soon as the truck gets warm, but the EEC plug hasn't been jumpered at all........

 

Run the KOEO test to see what codes might be present. Don’t guess at what is wrong and throw your wallet at the problem. More often than not you end up replacing good OEM parts with aftermarket junk.

You should be able to replace just the drain plug gasket.

If everything is greasy it will be nearly impossible to find the leak(s). Degrease the whole bottom of the truck.

You might be better off finding a replacement axle at the junkyard cheaper than paying someone to repair/ replace the bearings In your current 8.8. Just make sure the gear ratio is the same.

 

I've done this a while back, I have seen many threads here where people have done just that: replace good parts with aftermarket garbage. Here's a quote from another thread I made which has since closed out:

Not sure any of these are life threatening and no, I haven't checked codes since then. It's just such a long process might have to invest in one of those cheapo OBD I Ford readers........

See that's the thing, I did replace the washer that goes between the pan and the plug once already, still leaking! Might try it again, the washers are fairly cheap.

I'm ashamed to say I had just thought of that after I'd already started the thread. That will be the first item of business and I'll report back in.

I've also considered this as a possible way to go. There is a whole lotta play in the rear end anyway, it may be time to locate a parts truck and see if someone is willing to sell the axle. Right now it's a 3.55 open, upgrading to an LS from an F150 may not be such a bad idea..... I'm assuming any Ford 8.8 from 87-96 ought to work?

 

if JY lets you walk around and look, check door jamb stickers, axle code H9 is 3.55 LS.

 

You failed to mention that you already tried replacing the plug gasket. It could be the threads in the pan are stripped. Does the drain plug get tight or not?They leak from the valve cover if not using the improved rubber with steel core gaskets. Also from the oil pan and occasionally from the intake manifold.

There should at least be one seal between the transmission and the transfer case if not two. It has been a long time since I have had one apart. They do not share atf so if the transfer case is overfilled it has to be coming from the transmission.

So.... what did you do to address the EGR faults?

Yes. An 8.8 from a Bronco or F-150 will work. I believe they started putting the sensor in the rear around ‘86 but I’m not 100% sure about that. My ‘87 Bronco had one.

 

That's a great idea torq'ta. Aint much else to do around here might as well canvass the local JY maybe they'll have reasonable prices....

Yep, that's my bad, I thought I had said the crush washer was new. Guess it pays to proofread. The plug will tighten up just fine and by looking at it the threads don't appear stripped. All I know is I can see droplets of oil on the plug, and the small oil puddle under the truck is directly below the oil pan. It's tough to work on the Bronco as it's my brother's only vehicle and he drives to work every day. We will get it de-greased tonight and report back in when we discover where its leaking.

As for transfer case, It could be that seal is bad and fluid is overfilling the t-case causing it to leak, but the transmission dipstick showed a full amount of fluid (Checked in Park, running, transmission was warm). Once we get it degreased we'll figure out some more to do.

On the EGR codes, at the time I pulled the codes (Feb. 2019) I was chasing a no-start issue and so didn't mess with it. I know the vehicle has an exhaust leak, hence the lean code. I'm not too great with electricals but am happy to make a pass at testing on the EGR valve.

As to the axle, that's good info. Yeah ours has what could be the place for a sensor, though couldn't tell you what is currently inhabiting the hole. Looks like maybe a VSS was plugged in there and then somebody broke off the connector? The speedometer on ours gets a readout from the back of the transfer case I believe so I'm not sure if it matters.

 

On that year truck the sensor in the rear diff is for the RABS system.