DIY - Rear differential & manual trans fluid change tips and tricks by CN90

[BosBmw540]

repost another great Write-Up by CN:thumbup::

http://bimmerboard.com/forums/posts/189240

[jvcajita]

i know this is a stupid question...but it would be more dumb to not ask it...here goes the flame thrower...

is the procedure to change the rear diff fluid the same with manual and automatic transmission?

[540 M-Sport]

Yes

[Waveho]

I did my tranny last week and filled with Royal Purple Synchromax. BIG difference! Much smoother shifting! Great writeup on this. Will do the differentials next.

NOTE: The fill hole for the manual tranny on the 540 is on the opposite side from that in the writeup! First I though O my god what happened to my fill hole bolt! It's on the driver's side..... whew!

Yes, the rubber mallet is absolutely a must, in combination with a heavy wrench--the bolts are torqued to unearthly tightness....

[e39man]

i understand that the fill plugs on the tranny are a pipe thread. does anyone know the torque specs? I have an 01 M5... are the fill and drains in the same location? i just got this car, and i am disappointed how crappy it shifts. it is like i am breaking up turds in the tranny with the shift forks. i am hoping MT90 fixes this, because it did wonders on my mazdaspeed3. will i notice any difference doing the differential too?

[leeS]

This probably applies to many Models but I happen to have had to figure it out doing a differential oil change on my 1999 528IT.

You MUST have a 14mm hex wrench to remove and replace both the filler and drain plugs on the differential.
Of course this is an odd size that is not readily available and costs about 30$ if you order one from Sears, Lowes, Snap-on, etc.
You will probably only use it once or twice during the life of the car and then only need it for 15 minuites or less.

If you go to the hardware store bring a 14mm crescent or socket wrench for size comparison. go to the loose machine nuts/bolts section. go to the SAE (American non-metric) area. You should find that a 3/8" diameter hardened machine bolt with hex head has a head that will ft the 14mm wrench. get one about 1.5" long (thread doesn't matter) and two nuts to fit the bolt.

Screw the two nuts down on to the bolt leaving about 1/2" space between them and the head of the bolt. tighten the two nuts together to lock then in place.

Use the head of the bolt as the 14mm hex wrench head to fit into the drain plugs and use a 14mm crescent wrench to turn the bolt/wrench.
A couple squirts of PB loosening spray and a few taps with a hammer to the wrench and everything came apart easily without buggering the drain plugs.

HINT: The fit was snug on mine and I had to lightly tap it into the drain plug female hole.
I also had to tap and wiggle it a little bit to remove the tool from the plug.

Total cost less than $2.

FWIW

[riro424]

For those who are near an AutoZone, they sell a set of 3 large hex bit sockets (12, 14 & 17mm) for $10. They are 1/2 drive so using an 18" breaker bar will easily loosen the diff plugs.

[rc67]

I have a 2000 540i m sport 6 speed and it has 112k, but still runs like a champ except from 1st to 2nd gear it kind of crunchs a little. I want to change my trans-fluid as well, but how long should I wait til the next change out once i've done this first one?

[Ågent99]

I did my tranny last week and filled with Royal Purple Synchromax. BIG difference! Much smoother shifting! Great writeup on this. Will do the differentials next.

NOTE: The fill hole for the manual tranny on the 540 is on the opposite side from that in the writeup! First I though O my god what happened to my fill hole bolt! It's on the driver's side..... whew!

Yes, the rubber mallet is absolutely a must, in combination with a heavy wrench--the bolts are torqued to unearthly tightness....

:thumbup: Yes, ALWAYS remove the fill hole FIRST before you start draining! ;)

[mic0ne23]

i got a 2000 528i with "LIFETIME" maintenance free tranny so they say. does anyone know any body with the same tranny and have they done the fluids on them? its an automatic btw

[Consciousone]

Can anyone tell me how much fluid the 540 6 speed takes? I just changed to the RP Synchromax and it took under two bottles? Is this normal?

[Waveho]

Can anyone tell me how much fluid the 540 6 speed takes? I just changed to the RP Synchromax and it took under two bottles? Is this normal?

Yes. About 1 and 2/3 quarts of RPS is what mine took.

[cbxsage]

I would like to change the gear oil in both the trans and the diff, can anyone tell me what the weights and capacities are for my 98 540 6 speed manual?

Thanks

[Waveho]

I have the same car. All the info you need is in this thread. See the link at the top for a frame-by-frame write-up for manual tranny fluid replacement as well as the diff. As for your tranny, I HIGHLY recommend Royal Purple Synchromax. Find it, use it, love it.

[^ECKS540i]

yeah, my gears first through second are gettin crunchy on me too.. I guess it's about that time for me to do mine! I can get that Royal fluid anywhere or a designated place only?..

[Waveho]

yeah, my gears first through second are gettin crunchy on me too.. I guess it's about that time for me to do mine! I can get that Royal fluid anywhere or a designated place only?..

Do a search at amazon.com, buy.com, or shop.com for royal purple synchromax prices at online dealers. Order 2 quarts for MT. You can also check their website at royalpurple.com. My local shops usually carry some Royal Purple product or another, but rarely the RPS.

[E39music]

Can we use this funnel trick to fill the Steptronic ATF? I try to avoid having to claw under the running car hand-pumping little fluid at a time out from each ATF quart bottle.

What do you guys think?

[Waveho]

I don't see why it wouldn't work--only keep in mind that the MT takes less than two quarts, whereas the AT takes much more and will take a bit more time to fill.

[E39music]

I have never seen people did it this way on the Auto tranny. I know that I need to fill ~6qt. if I drain and change the filter on my tranny. Definitely, pouring it in using gravity should be easier than hand pumping it in squeeze after squeeze. Will try and see.

I don't see why it wouldn't work--only keep in mind that the MT takes less than two quarts, whereas the AT takes much more and will take a bit more time to fill.