Continuing to do maintenance on my new to me 05 v8 LR3. The previous owner spent a lot of time on the beach and the rear diff housing is very rusty. I tried doing the rear diff change myself but couldn’t get the fill plug to budge. I took it to a shop and had other work done (transmission service/pan conversion), drive shaft, front diff change. But they called me twice on the rear diff …..first to express concern they might damage it trying to change the fluids and after I insisted then when they couldn’t get the fill plug loose and said it would need to be drilled out.

I paused at that point. I’m 99.9% certain it has the rear locker (vin decoder, full sized spare, visual inspection of locker motor on diff) and when I tried to source a rear diff with a locker it looks like they really aren’t available. There are a few places that have rebuild kits but no one with even a rebuilt rear locker.

Just a bit conflicted as to what to do. Car runs great now.

 

If it has the e-diff the oil is “special”, as I’m sure you know, rather than 75W90 API GL-5 stuff that goes in the normal front and rear diffs.

While we haven’t seen any pictures of the surroundings of the fill plug but here are some ideas for you. Drilling it should be the very last thing to do.

• wirebrush the rust away from the around the plug and from the plug itself
• soak it for a longer period with CRC or similar fluid
• repeat the above until the plug itself looks decent
• Use induction to heat the plug and the surroundings and proceed very carefully

edit: and yeah, don’t mess with the drain plug unless you get the fill plug open 😂😎

 

Yep, have two bottles of the OEM locker fluid.

Unfortunately looks like the mechanic took a small chisel to it. To be fair it was so rusted, I couldn’t get a hex driver into it.

I do have an extractor set (male reverse threaded). My thought was to do some prolonged soaks and give it a try. I’ve have real success with a 50/50 mix of citrus stripper and atf fluid with very rusty things before.

 

Worth repeating...

Have you tried using an impact? I would assume the shop did. I would keep it set low, but impacts can do wonders to remove large plugs like this.

 

Took a good look today. Pretty sure I could get the drain plug out but the fill plug is so rusted and stripped that I couldn’t get any easy out to even stick, let alone apply any force. I agree it needs to be drilled. The fill plug is in a really tight space and I don’t have the tools to drill it. The whole rear diff is so corroded I also concur with the mechanic there is a risk to disrupting a a seal by pounding and torquing on this thing.

I think I’m going to leave it and work on sourcing a locking rear diff from some place to have on hand for when it goes.

 

Update here, I can’t get access to the full plug site to do a straight drill tap without taking my exhaust off. The exhaust brackets are really rusty as well. I’ve tried short drill bits and a right angle drill. The space is just too tight. As much as a hate leaving a job undone, I’m going to leave it alone.

May start sourcing a replacement rear diff.

 

If you replace the rear diff, the exhaust will have to come down anyway. Also the exhaust is dropped by the rubber isolators, there are no brackets to remove. But I am guessing you maybe mean the hangers are so bad you probably cant even slide off the rubber isolators? They are a pain even on clean ones. You could order new isolators and sawzall the existing rubber ones in half, then it would be easy to work off the leftover bits and clean up the hangers. The bigger pain will be taking apart the exhaust at the nut/bolts after the cats. I ended up cutting mine, drilling out the studs and using new hardware.

 

You are correct. Everything is so rusty. Just don’t feel like doing it at this time for routine maintenance. Feels like I will be opening a can of worms.

 

I don’t think I need to remove the exhaust. If I could just get it to hang down a foot or so it would be fine.

Are you saying if I cut this part off:

https://www.roverparts.com/exhaust/h...RoCgdoQAvD_BwE

that that’s what’s holding it up?

it’s so rusty I couldn’t tell what’s what.

 

Yeah, there are a few hangers like those. Not all the same. Two at the far back mufflers. Then a couple in the middle area around the large resonator. They simply slip on and off - at least wen new. When old, you have to really molest them to get them to slide off the metal hangers.