How To Change Your Gearbox Oil

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Re: How To Change Your Gearbox Oil

Post by Supercell » Sun Oct 02, 2016 11:35 am

A big thanks to Marco_Polo for the gearbox and diff guides. I used these guides about 6 months ago to change my gearbox and diff oil. I'm not the most mechanically minded but I bought an oil gun as recommended and used redline for both, the guide was so simple to follow, so a big thank you.

It's good peace of mind, my car was on roughly 50k, the gearbox oil wasn't too bad, but the diff oil came out like black water! On that basis I'll change the diff oil annually.

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Re: How To Change Your Gearbox Oil

Post by Biccus1 » Sun Oct 02, 2016 3:47 pm

My m sport has 28000 on so going to do the diff in couple of weeks but gearbox next year thanks for the guides :)

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Re: How To Change Your Gearbox Oil

Post by mctga » Sat Oct 22, 2016 6:04 pm

I changed the gearbox oil on my manual M135i today. Car only has 15k miles on it so it definitely didn't need doing but I thought I'd do it as preventative maintenance. The fluid that drained out was black with specks of metal in so I'm glad they're not in there now. I refreshed with OEM MTF LT5 fluid. Fairly straight forward with the car on ramps on the driveway but it was tricky undoing the fill bolt with limited access wriggling around under the car and it was seized on too so I had to use a breaker bar.

For reference the steel fill/drain plugs require 45Nm tightening torque.

Shouldn't need to be done for another 30k now.

Estoril Blue F20 M135i 6MT
E87 120i

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Re: How To Change Your Gearbox Oil

Post by rusty13 » Sat Jul 01, 2017 2:34 pm

Marco - looks like your how-to has been ruined by photo bucket!!

So here are the exports of the official BMW ISTA+ instructions for the job for the M135i: ... 1.pdf?dl=0 ... 2.pdf?dl=0 ... 3.pdf?dl=0 ... s.pdf?dl=0
M135i Estoril Blue - 5 Door - Manual

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Re: How To Change Your Gearbox Oil

Post by Lew1989 » Mon Sep 11, 2017 11:48 am

marco_polo wrote:
Mon May 02, 2011 9:30 am
This is a guide for changing your gearbox oil, this relates directly to a 120d, but I'm sure it would be a similar procedure for any BMW. I did mine on a ramp, which is preferable to stands.

Before you start, you'll need 2 litres of gearbox oil; a pair of rubber gloves (unless you prefer the spare bed), an 8mm Socket/Ring Spanner; an 8mm Allen Key; something to catch the old oil in; and tool/method for refilling the gearbox. I used one of these:


It's a 500ml 'Silverline' Oil Gun, basically a big syringe, which makes things very easy. About £8.

For best practice, you should also renew your gearbox plug seals, which involves buying 2 new plugs from BMW. About £4 each. Take the last 8 digits of your chassis number into your local friendly parts dept to make sure you get the correct items.

The oil BMW recommend is made by Castrol, but I wanted to improve a slightly notchy gearchange I was suffering, so went for 2 litres of Redline MTL, as recommended by Redline (and Blackbmw116 on here) for notchy BMW manuals.

Start by removing the eight 8mm screws with secure the transmission portion of the undertray. The under tray will now be loose, but will require a 45 degree twist toward the OSR to drop from the car.

Under-tray unscrewed, just before 'twist' removal:

You'll now have a good view of the gearbox. Have a quick look at your new plugs, this will help you identify the Fill and Drain Plugs on your casing (and also how long those threads are for the next stage). Bear cleanliness in mind too, you don't want to knock any crud inside at any stage, or you could do more harm than good.

Fill & Drain Plugs:

Slacken the top Fill Plug first. Don't remove it yet though. If you remove the Drain Plug first, and have difficulty in removing the Fill Plug, you'll be left stranded with a car with no oil in her, and a headache! (thanks Anthony) Pop your gloves on (old gear oil is nasty stinky stuff), and with oil catch-can/tray in hand, remove the Drain Plug. As you've left the Fill Plug loose but still in it's hole, the oil won't come rushing out. My old oil was like black water, no wonder my change felt crunchy, 'sealed for life' my arse. Sealed to die, more like it. Once you've lost about a litre and a half, take the Fill Plug out, and go and have a cuppa, to let it drain for a while.

Nice brew? Good. Now it's refill time. Gloves back on, and fit a new Drain Plug in the bottom of your box. The seal does the work, not the Plug, so there's no need to go swinging off the Allen key with a great big long bar! Fill the gearbox with roughly 1.6 litres of nice new oil. I simply sucked it out of the bottle, and blew it into the fill hole. When it's full, it will just start trickling out the fill hole.

Refilling with Redline MTL via Oil Gun Syringe:

Now you just need to refit the Fill Plug, and replace the undertray. Again, no need to go crazy when torquing up the 8mm undertray screws.

If you went with the Redline MTL, go and enjoy your new smoother gearchange. The Castrol camp only get to feel smug about increasing the longevity of the box I'm afraid.
Is this still a guide to go by? I'll be attempting this myself within the next few weeks
'58 N47 120d E87

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Re: How To Change Your Gearbox Oil

Post by marco_polo » Mon Sep 11, 2017 11:49 am

Silver F21 M135i - ManBox - HK - Adaptive + Eibach Pro's - BBS CH-R's - BMWP Drexler LSD - TMC Piggyback - M4 LCA's - aFe Dry Filter

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Re: How To Change Your Gearbox Oil

Post by supercati » Wed Dec 27, 2017 3:04 pm

I'm going to attempt this soon to my 130i. Ordered 2L of gearbox oil.

DIY is perfect! I just have one question:
I need to fill 1'6L, if I try to fill more, oil won't come in and will be getting out thorugh the same filling hole? I'm afraid to overfill if there's some old oil inside the gearbox :roll: .

Should I fill until the limit then and this will be 1'6L inside the gearbox?
130i E81 2007 LHD - Sparkling Graphite Metallic / Boston Terra - CDV Delete - 135i ESD with resonator delete - LED Blacklines - RIP :(
130i E81 2008 LHD - LSE / Boston Terra - Complete HiFi Retrofit - CDV Delete - LED Blacklines

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Re: How To Change Your Gearbox Oil

Post by Trojantrow » Wed Dec 27, 2017 3:31 pm

It's a bit of a biatch to be honest as you have to make sure you suck it all out. Use a thin tube so you can get to the bottom. That's the biggest problem. because you read online how much the gearbox takes and then it seems not to take anywhere near that amount. It's obviously because you didn't get it all out.

But if the car is level. And you start pumping it in, when it starts coming out of the same hole, it means you have finished. Simple as that really. If the car is not level. You will either not put enough in or too much...a bit either way won't make any difference so don't worry too much about it.

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Re: How To Change Your Gearbox Oil

Post by rhodesj971 » Sun Jan 21, 2018 2:10 am

Just completed this on my 2009 123d (along with engine oil, fuel and air filters...) and it feels like a new car. Gearbox is amazing now. Great guide.

Did it with the front of the car jacked up. Drained the oil (soupy black with flecks in it...), fitted new plug (I used M18 x 1.5mm sealing plugs off eBay - ended up being a slightly shorter length, but doesn't matter) using the gooduntight torque setting, and put both bottles of Redline MTL in with the Silverline syringe. Used up both quarts of oil - never overflowed, but I pinky tested it and could feel it just inside the hole so figured it was fine. Re-sealed and car felt new again. Have done 30 miles of 'spirited' driving and it's been fantastic. Can't recommend enough.

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