Where to buy a Differential?

Differential Photos


Top of casing usually has
a tag with the Ratio.


My 3.46 differential from an
automatic 2002 325i

Where to Buy

There's a couple of places to buy differentials. Firstly, straight from BMW, but a brand new differential is going to run you about $1300. The most common place to pick up a differential is from a salvage yard. The most readily available gear ratio, 3.46, is going to cost you around $200-$350. Less common ratios, like 3.23, and 3.38 are going to cost you more. Just remember that prices vary WIDELY between salvaged yards. One place might charge $200 for a differential, and another place may charge $700 for the same thing. So, call around.

A great place to check is car-part.com for used differentials. They'll really heavy, so expect to pay about $50 to ship.

A typical search will be
Select Year: 2000
Select Make/model : 323
Select Part: Carrier (see also Differential)
All Areas/Select an Area: {leave as default, it's best to search all salvage yards for the best price}

What to search for:

3.07 - 323i/ci (m), 330i/ci zph (m), 330cic/xi (m)

3.15 - 325i/ci (m)

3.23 - 325xi (m) - Very Rare to find in a salvage yard

3.38 - 330i/ci (a) - These are harder to find and usually cost more. (Non-US, also check 316/318/320)

3.46 - 323i/ci/cic/touring (a), 325i/ci/cic/touring (a), 328i/ci (a), 323i/ci (a), 323i/ci (a) - The most abundant and easiest ratio to find.

3.64 - Z4 2.5 (a) - Very Rare to Find in a salvage yard

3.64 - E46 M3 - You'll need addtional hardware to get it to fit.

Common Ratios for Differential Swaps:
323/325 owners usually go with 3.38 or 3.46.

328/330 owners usually go with 3.15, 3.23, 3.38 or 3.46.

Use my E46 Gear Ratio Calculator to help you decide!

What about LSD?
BMW doesn't offer an LSD that will fit normal E46s. LSDs from E36 / E46* M3s won't fit (at least without more modification). Kaaz does off an LSD that will fit into some of the E46 carriers. BMWDon on E46fanatics was able to build up an LSD using the Kaaz unit with a 3.46 differential carrier.

http://www.kaazusa.com/

*It's been reported that the E46 M3 differential will also bolt up to non-M3 E46s. You'll also need M3 axles and the M3 drive shaft. Since I haven't actually done this swap and I don't know what involved, it will not be covered in this write-up. If someone has this info, e-mail me, and I'll add it. E46 M3s use a 3.64 final drive ratio. They're able to get away with using such a high ratio since they have an 8k RPM rev limit.

©2005 sycE46