my 3.15 dif questions

A thread in another forum got me researching:
Background:
On 2000 (edit: 1999) and up model year 540i6 (manual trannys) it is a well know and often puzzling fact that the 3.15 dif swap (found in all auto 540i's) will kill cruise control.
The question has always been WHY!
The INTERESTING thing is that a poster on another board had failure symptoms of his 98 auto tranny ignition switch that sound a LOT like the 3.15 failures that DaveZ and I had with 3.15's. The poster's cruise would disengage, the light would stay on the dash. He'd have to restart the car to get it back, etc.

Sooo lets look at ETK
ah HAH! (maybe)
61-32-6-901-962 is for all 03-97 and up automatic
61-32-8-363-706 shows 'up to 05/00, Manual' It's food for research thought. ie if your dealer says the switch on your 05/00 or higher car is this one, all bets are off.
61-32-6-901-961 is for a 2003 (and presumably any car after 05/00) manual.

So, can we venture a guess:
3.15's seem to work in 99's and below. According to THIS line of theory, SOME 00's (those built before May, '00?) MAY work with the 3.15.

Dont you just wonder
if an 8-363-706 (for cars up to 05/00) -or- if a 901-962 will FIT in a manual car made after 05/00? And Dont you just wonder if THIS would solve the problems killing cruise with a 3.15 and a manual tranny 540i6?

So who's gonna test it! (I have a 2.81 quaiffe. I aint touchin it!) Somebody step up!

well... if it's any consolation, i'll be getting a M5 diff in and i'll be putting it in. supposely that would kill the cruise too but mine's a 98 so.... 8cross finger*

PS: good find!!

Originally Posted by chivas

well... if it's any consolation, i'll be getting a M5 diff in and i'll be putting it in. supposely that would kill the cruise too but mine's a 98 so.... 8cross finger*

PS: good find!!

Nope- doesnt happen on 98's. Only '00 (edit '99) and higher.

but can't you find out when your car's made via realoem?

found out mine was built 7/98.. one of the last non-vanos out there.

Originally Posted by chivas

but can't you find out when your car's made via realoem?

found out mine was built 7/98.. one of the last non-vanos out there.

You can find out when your car was made by looking in your driver's door sill.

The problem with cruise being killed doesnt occur in 97-99's as far as anyone has reported. In fact, I have first hand experience with it working in a '97 540i6.

In a 2000 (edit- '99) 540i6 or higher, cruise fails with a 3.15 dif. I've also experienced THAT first hand.