Changing rear axle - 535i

[Rymark]

Has anyone swapped out the rear axle on their E31 with a 535i axle? I am considering it in order to gain quickness to my 1995 E31. I would be interested in any pitfalls or successes. Thanks.

[olinjohnston]

Are you talking about the rear axle, or the differential? The rear suspensions on the two cars are VERY different and parts cannot be swapped. The USA 535i has a "medium" case differential and is incompatible with the E31. You never said what model 8 you had either, and that also determines which diff is an upgrade in gearing.

[Rymark]

Sorry, yes the differential. I have a 95 840Ci. Have you done a change out?

[olinjohnston]

Sorry, yes the differential. I have a 95 840Ci. Have you done a change out?

Yeah I wrote the DIY:

https://www.bimmerforums.com/forum/s...LSD-into-840Ci

[TxGR8White]

The only diff from a 5 series that will work on the 8 is the 3.91 LSD from a 91 M5. If you have an 840, that won't work too well anyway. What you want is a 3.64 from a M70 automatic 850.

[JK840]

E32 750Li had a large case 3.64. Some were LSD. I'm very please with one in a 840Ci 5 speed automatic.

[Rymark]

Thank you. This information helps. I also appreciate the two different ratios and why you like one over the other.

[rjbaren]

If you ever plan to change to a manual trans the 3.15 is another great ratio choice. The Euro Sport 6 speed cars I believe came with a 3.08.

[tangcla]

The Euro Sport 6 speed cars I believe came with a 3.08.

That's correct. I have one.

[TxGR8White]

Thank you. This information helps. I also appreciate the two different ratios and why you like one over the other.

It is not about liking one over the other. The 3.91 is just too "short" in the gearing for the 5-speed automatic. The car will be turning much higher rpms at cruising/highway speeds. You will get a bit quicker launch, but the engine will be turning much faster than what you really want.

[dragon850]

It is not about liking one over the other. The 3.91 is just too "short" in the gearing for the 5-speed automatic. The car will be turning much higher rpms at cruising/highway speeds. You will get a bit quicker launch, but the engine will be turning much faster than what you really want.

3.15 or 3.64 are perfect for the 5 speed auto. 3.73 LSD is very fun. Would not go higher than that.

[dudu850]

E34 535is ( EURO ) used 3,64 LSD 210 case. Direct fit into an earlier 850iA ( EURO ).

[razman850]

What is the euro sport 6 speed?

[tangcla]

What is the euro sport 6 speed?

Stock E31 840Ci 6MT is 3.08.
Not sure about the 850i.

Sent from my SM-G930F using Tapatalk

[razman850]

Ok, i missed the OP stating he has a 95 840ci, euro 850 manual has 2.93.