I decided to change the transmission and differential fluids today. My
03 M5 has 48K miles and I had ordered some Royal Purple for the tranny
and some Redline for the diff. I decided to start with the tranny.
I warmed the car up by driving for a while. I had read the posts here
regarding changing the fluid. I got the car up on my jack stands by
driving the car up on my ramps and using my new jack bar to lift the
rear of the car using the chassis lift pads. I then put jack stands under
the car so the chassis was perfectly level.
Ok, so I know enough to remove the fill plug first. I get my 17mm socket
and my breaker bar and give it a tug. No luck. I try again.... Mind you
I'm using a 1/2" socket drive with what must be a 17" bar. I try again
and this time it twists because I can't get a straight pull on it. You can
probably see where this is going. The fill plug was extremely tight.
To get the drain plug out, I ended up going to Sears and getting a set of
bolt outs. These helped since I had stripped part of the head and my
17mm socket wasn't hooking up well. I then took my propane torch and
heated the drain plug for about 60 seconds. I tapped the bolt out onto
the drain plug and attached the breaker. Finally it gave
The drain plug was easy. It was tight, but no where near the fill plug.
They must have had a gorilla put the fill plug in with a impact wrench
and a sledge hammer.
With the fill plug out, I removed the drain plug and a torrent of tranny
fluid came out. I'm glad I had a wide deep pan or it would have been
a mess. It's best to loosen the fill plug then remove the drain plug so
that the fluid drains slower. Once it's fairly empty remove the fill plug
and allow it to completely drain.
The car was hot so the fluid drained quickly. ( The drive to Sears heated
everything back up. ) Once it was fully drained, I replaced the drain
plug, torqued it to 37 ft/lbs and pumped almost 2 quarts or Royal Purple
into the transmission before it started to run out. I put the filler plug
back in ( after fixing it up a bit with a file to square off the flats ) and
torqued it to only 30 ft/lbs.
The fill plug is fairly beaten up. I'd like to replace it with a new one. Does
anyone know where I can find a new one of these ? I checked Pelican
and did a search on Google with no luck.
The differential was very easy. Drove a bit to warm things up again.
Used a 14mm hex driver to loosen the fill plug, and drain. Filled with
Redline and torqued the plugs to 37 ft/lbs.
Car drives well and shifts very smooth. I just need to find a new fill plug
for the transmission and she'll be good as new.