Rear diff filler plug

[irish]

Hey guys, I am sure someone will have had this problem somewhere down the road.

I bought out 2009 ML GLX-R 3.2 a few months ago.

While under the car the other day running power to the rear of the tub I noticed that the rear diff was weeping oil from the filler hole. So off to Mitsui and picked up a new copper washer as to me that was obviously going to be the problem, whoever had last checked the oil level never used a new washer.

We derr, wrong... The bolt will not come out, it spins so that to me means someone has over torqued it and stripped the threads either in the diff housing or the bolt has stripped.

So the question is how the hell do I get the bolt out? I have tried gingerly getting a flat blade driver between the edge of the bolt head and diff housing while trying to back the bolt out, no luck...

Am not overly concerned, had a good look underneath and it's not flicking oil everywhere, just dripping down the back of the housing and onto the ground. Am heading down south today about a 1100km round trip, will just keep an eye on it I guess. But yer if any of the more knowledgeable forum members know how to get it sorted i would really appreciate the feedback.

Cheers

Tim

[Cowboy Dave]

Hmm. I wonder if it might come out better at speed like with a drill or impact driver? Other than that maybe use multigrips or vice grips so you can exert an outward pull as well as the rotation? What's the plan for once it's out though?

[viking shippy]

I'd check the level before you go....
I'd try Dave's suggestion with a large vice grips..
More than likely it's the plug that's striped it's made of softer steel... we hope... (but could be the thread in the diff also this will need a rethreading invert.such as a helicoil)) Be shure when you get out all the slivers of thread still in the diff housing..thread..if that don't work...
Next drill and tap a bolt into the Plug so you can devise a way of applying a out and downward pressure to the bolt whilst turning the plug ..with a spanner
Good luck and let us know how you go...

[SEJ GLX-R]

Can't check the level with the filler plug stuck in there

[fridgie]

Can't check the level with the filler plug stuck in there

x-ray specs

[viking shippy]

Oh it's the top one..your running the risk of diff damage if you carnt check it ..how long has it been leaking...how much have you lost?

[Cowboy Dave]

If the filler is leaking and you're not doing steep hills then you'd have to think there's still a fair bit of oil in there?

[SEJ GLX-R]

If it is the filler plug leaking it must be very close to the correct level otherwise it wouldn't be leaking.

[Cowboy Dave]

Yeah that was what I was thinking - was also wondering how you could overfill a diff, unless you parked it on a steep slope or something.

[GLRkenny]

Yeah that was what I was thinking - was also wondering how you could overfill a diff, unless you parked it on a steep slope or something.

You can pump too much oil in and put the plug back in before its drained to the correct level, the oil pump will pump more than what will drain out if that makes sense

[macca002]

You need to weld a big nut to the filler plug - on its side (90 degrees). Then feed through a long bit of threaded rod and use this to pry outwards as you turn. It will eventually come out. If you are having a real hard time with it, then a ratchet strap attached around rear towbar/ball under tension and attach both ends to the threaded rod.
Turn 90 degrees, retension, turn, retension, turn. Be careful as the plug may let go and pop out with a bit of force.

If the bolt's thread is stuffed, then use a HT bolt to screw in and clear out the thread. If the diff thread it stuffed, then helicoil.

Once its sorted, dump the diff oil. Refill with cheap stuff. Run through a coffee filter. Refill oil into diff. Run it through again. Repeating until no evidence of metal in the filters. Refill. Go for a short drive. Run through filter. Do this until you are happy that you have all shavings out.

Fill diff with fresh oil. Go on your trip. When you get to the end. Dump out oil again for good measure, and refill.

Hope this helps

[brodical]

Bloody good idea macca..

[viking shippy]

If it is the filler plug leaking it must be very close to the correct level otherwise it wouldn't be leaking.

Gee of course doh
Filler plug my bad

[smlr]

Get a big set of side cutters between the plug & housing & then use a rattle gun in short bursts. The side cutter jaws should squeeze between the plug & housing hopefully levering the plug out. Good luck.

[ag9111]

Blind drill and tap the centre of the filler plug with a largish thread, say 10mm. Add a bolt and that will give you something to add some pulling force as you rotate.
Blind drilling is not drilling all the way through.

[macca002]

Bloody good idea macca..

Had to do it on a gearbox. Ali thread gave way on a seized filler bolt but didn't give up without a fight.

[irish]

Hey guys, thanks for all the tips, ended up taking the Commonwhore for the trip and i will tackle the bolt when the weather here in Perth calms down a bit, do not fancy rolling around on the ground in the pouring rain

For that matter the missus just reminded me we took out an extended warranty on the car so maybe the dealership can fix the problem Shall make a phone call in the morning..

[viking shippy]

Hey guys, thanks for all the tips, ended up taking the Commonwhore for the trip and i will tackle the bolt when the weather here in Perth calms down a bit, do not fancy rolling around on the ground in the pouring rain

For that matter the missus just reminded me we took out an extended warranty on the car so maybe the dealership can fix the problem Shall make a phone call in the morning..

Ha ! ...they are probably the ones who striped the bolt in the first place..

[aimstix]

This happened I me when I last checked the rear levels I noticed it was stripped. All I did was get a chisel and between the diff and plug gave it a gentle tap so there was backwards tension on the plug and spun it with a 15/16th spanner and it came out..

[snakesoup]

so I changed the oil in my front and rear diff after work today 35k on the clock and first time they have been changed, did the rear first which has factory locker and was surprised to see on the plug magnet quite a bit of metal and also some drilling swarf.. wtf?? magnet did its job by the look but was still a little surprised. any one else had this?? like it wasn't cleaned out properly from factory. the front on the other hand was clean as a whistle
for anyone with the hex plug on the drain "rear diff" it is a 10 mm hex key if your thinking of doing it, I bought the 1/2 drive hex bit and the plug came out easy as.

[harland]

Yep front and back diff had a concerning amount of metal debris built up on at 20,000km. I always thought the front diff was noisy, like the transfer was trying to mesh or something abnormal.

[explorer.dave]

Old thread but here goes,
MN with 4.1 diff (standard NO locker), oil leaking from filler plug, my question is how do you check the level? I was told by a HV fitter to put your index finger in and down and oil level should be at tip of finger as a "rule of thumb" pun intended.
Cheers

[NowForThe5th]

Full is to same level as bottom of filler hole. Minimum is 8mm below bottom of hole. Vehicle level, of course.

[explorer.dave]

Cheers Chris