540i Transmission INTO E39 M5?

E39_GixxerThou · 24th April 2012, 16:36

I have a problem with my transmission in my 2000 M5, I came across a thread where a transmission from a 540i will work. According to realoem and few places its the same part number, same transmission with few different internal parts. Is the transmission ratio the same? Has anybody bolted one up to an M5 and have it work fine? What is needed to be modified before it working flawlessly? What is the SHIFTER POSITION SWITCH?

Strike · 24th April 2012, 17:15

I could be wrong but I believe I read once that the ratios are in fact different. I would assume the shifter position switch is the gear indicator switch on the side of the transmission near the reverse switch. One of the electrical connections that has to be removed before pulling the tranny.

E39_GixxerThou · 24th April 2012, 17:17

Quote:

Originally Posted by Strike

I could be wrong but I believe I read once that the ratios are in fact different. I would assume the shifter position switch is the gear indicator switch on the side of the transmission near the reverse switch. One of the electrical connections that has to be removed before pulling the tranny.

Thats what I figured and i read from a member that tapped into the 540i tranny said he would just skip it if he was to do it again!

Strike · 24th April 2012, 17:23

Yes, I think TIS refers to it as a gear detection switch. I don't know too much about it personally but I would assume it probably doesn't sense if the transmission is in each particular gear but maybe more which gate the shifter is in. Or just that it's in a gate vs. being in neutral. I'm not sure of the function of the switch but my best educated guess would be that it works alongside the clutch safety switch to make sure the starter won't engage while the car is in gear with the clutch let out.

meepmeep · 24th April 2012, 17:25

Pretty sure the ratios are the same. The 540 has a different final drive. Why do I suspect a run on 540 transmissions...time to stock up.

E39_GixxerThou · 24th April 2012, 17:25

Quote:

Originally Posted by Strike

Yes, I think TIS refers to it as a gear detection switch. I don't know too much about it personally but I would assume it probably doesn't sense if the transmission is in each particular gear but maybe more which gate the shifter is in. Or just that it's in a gate vs. being in neutral. I'm not sure of the function of the switch but my best educated guess would be that it works alongside the clutch safety switch to make sure the starter won't engage while the car is in gear with the clutch let out.

Right. Obviously we dont have gear indicators on the cluster like automatic cars do, but he said he would have done it without tapping into the transmission. I think itll work without the switch but not 100% sure!

rao · 24th April 2012, 17:25

No info about the switch, but this is interesting:

Gear ratios on Getrag

E39_GixxerThou · 24th April 2012, 17:28

Ive read in a few different places the ratios are the same, they just carry a few different internal parts, and the M5 is more "beefier"

meepmeep · 24th April 2012, 17:30

"Beefier" until it gets stuck in 2nd.

Strike · 24th April 2012, 17:31

Looks like my guess on the switch is right. Read this thread:

fault code 80 "Switch Chain, Frictional Connection

I'm assuming the person in that thread you were reading said they wouldn't bother going back because it was going in a race car. According to this you would most certainly get a fault code and possibly even idle issues according to Raikku without tapping and adding that switch.