ML320 DIY: Spark Plugs, differentials and transfer case

7106 Views 10 Replies 10 Participants Last post by zbordas, Dec 6, 2017

bimmerdriver

Discussion Starter · Jul 2, 2011

Yesterday, I changed the spark plugs and the lubricants in the front and rear differentials and transfer case. The job was made much easier because of the excellent info on this site. I have a few additional comments.

For the differentials, I strongly recommend a 10 mm bit, not a 3/8 inch bit as some have suggested. I initially tried a 3/8 inch bit and it did not fit very tightly into the plug. (I had to put a lot of torque on all of the plugs since they likely had never been removed.)

When you change the fluids on the differentials, be sure to remove the fill plugs before you remove the drain plugs. Particularly on the rear differential, the fill plug is in a tight location. I had to put a wrench on the 10 mm bit and it was hard to get enough leverage to loosen the plug, as the plug was very tight.

Do yourself a favour and get an oil pump to fill the differentials and transfer case. Pumps are inexpensive and I can't imagine how messy the job would have been without one.

I used a "mercedes benz v6 engine spark plug boot puller" (aka, offset 17 mm open ended wrench). (See below.) The tool worked really well, except for the driver's side rear spark plug where there isn't enough room to pry with the tool. I got around that by using a flat nail puller to pry on the wrench. (See below.) It just fit between the wrench and the valve cover.

Also, particularly on the driver's side, it helps to have a mix of 3/8 inch extension lengths. I found that by using a 1 inch extension, I was able to rotate the socket easily between the head shield and the valve cover.

See less See more

Save

1 - 11 of 11 Posts

DrX

· #2 · Feb 16, 2015

A few additional tips for RHD ML owners planning to change their diff oil.

The routing of power steering lines along the crossmember limits the available space to remove the front fill plug. A 10 mm hex socket and extension isn't going to fit.

You need one tool to do it - a long 10 mm hex key (plus an adjustable wrench to turn it).

To refill, why use a pump when a length of plastic tubing and a funnel will do? A 10 mm external diameter tube can conduct 1.2 L of 85W-90 oil in 8 minutes. Avoid wasting any precious diff oil by attaching the tube to prevent slippage.

The torque specs for front and rear differential fill and drain plugs are 50 nm for all.

SCA Hex Key Set - Long Arm, Metric, 9 Piece - Supercheap Auto Australia

See less See more

Save

art_arev

· #3 · Feb 16, 2015

That's How I did it DrX on my 320. The only difference was while my wife was pouring the oil , I was under the car holding the pipe:frown.......It doesn't take long, plus it gives one time to reflect while under the car:laugh

Save

Reactions: 5

Michael Pillay

· #4 · Feb 19, 2015

For the diff service, I use this:

Multi-Use Transfer Pump

Save

1081674

· #5 · Apr 23, 2017

bimmerdriver said:
Yesterday, I changed the spark plugs and the lubricants in the front and rear differentials and transfer case. The job was made much easier because of the excellent info on this site. I have a few additional comments.

For the differentials, I strongly recommend a 10 mm bit, not a 3/8 inch bit as some have suggested. I initially tried a 3/8 inch bit and it did not fit very tightly into the plug. (I had to put a lot of torque on all of the plugs since they likely had never been removed.)

When you change the fluids on the differentials, be sure to remove the fill plugs before you remove the drain plugs. Particularly on the rear differential, the fill plug is in a tight location. I had to put a wrench on the 10 mm bit and it was hard to get enough leverage to loosen the plug, as the plug was very tight.

Do yourself a favour and get an oil pump to fill the differentials and transfer case. Pumps are inexpensive and I can't imagine how messy the job would have been without one.

I used a "mercedes benz v6 engine spark plug boot puller" (aka, offset 17 mm open ended wrench). (See below.) The tool worked really well, except for the driver's side rear spark plug where there isn't enough room to pry with the tool. I got around that by using a flat nail puller to pry on the wrench. (See below.) It just fit between the wrench and the valve cover.

Also, particularly on the driver's side, it helps to have a mix of 3/8 inch extension lengths. I found that by using a 1 inch extension, I was able to rotate the socket easily between the head shield and the valve cover.

Thanks for the information, ive got the pump. I am going to try and do it this morning, providing it doesnt pee down again.

Save

megadamp

· #6 · Apr 24, 2017

art_arev said:
That's How I did it DrX on my 320. The only difference was while my wife was pouring the oil , I was under the car holding the pipe:frown.......It doesn't take long, plus it gives one time to reflect while under the car:laugh

Like shaking ones head while looking at all the rust.

Save

Reactions: 4

Noodles

· #7 · Apr 25, 2017

Shoot, I just forgot I have not checked my blinker fluid or even the muffler bearings for almost two years.

Save

Reactions: 3

mattml430

· #8 · Apr 25, 2017

Last time I did my blinker fluid change I used the long life fully synthetic. It has been excellent. They have performed faultlessly ever since.

Sent from my iPhone using Tapatalk

Save

Reactions: 3

Noodles

· #9 · Apr 25, 2017

I may try that sealed for life fluid blinker assembly. It worked so well with transmission why not blinkers?

Save

Reactions: 2

C230 Sport Coup

· #10 · Dec 6, 2017 (Edited)

I'm proud to announce that I'm now an affiliate marketer for Kale Auto,
and can offer this quality blinker fluid at a steep discount to
benzworld members. Send PM to order

Blinker Fluid - $18.95 : KaleCoAuto.com, Your home for the rare, unusual, and hard to find auto parts.

GREAT Deals on 710 oil caps and Round Tuits as well as muffler bearings! Just in time for the holidays!!