Cement 863 Report post Posted September 12 Looking to change out the 3.38 ratio on my existing mid case E46 diff. Unsure which models the 3.73 and 3.91 came from ... I believe some X3 internals can be swapped in also which might provide additional options ? I'd prefer the 3.91 👍 Quote Share this post Link to post Share on other sites
Eagle 1660 Report post Posted September 12 Those ratios would have to be X3's, probably the 2.5 which is common as muck. Bear in mind X3's likely use the inferior standard roller bearings vs much superior taper ones found in most E46's. Id assume the crown and pinion are still the same dimensions so they can be interchanged, someone like Kane Barrie would know for sure. 1 Quote Share this post Link to post Share on other sites
Vass 821 Report post Posted September 12 E46 320i automatics came with 3.91 diffs. No idea on specifics or how interchangeable the internals are though. Quote Share this post Link to post Share on other sites
Cement 863 Report post Posted September 13 1 hour ago, Vass said: E46 320i automatics came with 3.91 diffs. No idea on specifics or how interchangeable the internals are though. Did they have a mid case diff ? I found this really good X3 chart this morning ... looks like the manuals are what i am after which must be very rare in NZ ? Maybe have to go full race car with the auto diff ratio at 4.44 http://tomic.ba/fs/cjenik/E83 Technik 0307.pdf Quote Share this post Link to post Share on other sites
Eagle 1660 Report post Posted September 13 2 hours ago, Vass said: E46 320i automatics came with 3.91 diffs. No idea on specifics or how interchangeable the internals are though. Ah forgot about those. Yeah don't know the ring gear. Might be the same with different flanges if you lucky Quote Share this post Link to post Share on other sites
HELLBM 1552 Report post Posted September 13 https://hellbm.com/product/bmw-e83-x3-differential/ https://hellbm.com/product/bmw-e83-x3-differential-2/ Quote Share this post Link to post Share on other sites
Vass 821 Report post Posted September 13 17 hours ago, Cement said: Did they have a mid case diff ? I honestly wouldn't know how to tell, could me small case? I'm yet to figure out the difference. Here's one I pulled from a 320i I parted out. They should be dime a dozen at any Pick-A-Part. Quote Share this post Link to post Share on other sites
Cement 863 Report post Posted September 13 Looks like from realoem that 316, 318 and 320 had the small case / 168K diffs, 325, 328 and 330 had mid case / 188K and M3 large case. Probably some weird diesel variants etc in the mix also. ssss 19 hours ago, HELLBM said: https://hellbm.com/product/bmw-e83-x3-differential/ https://hellbm.com/product/bmw-e83-x3-differential-2/ Thanks Ray, do you happen to know if the ring and pinion can be swapped into my existing diff ? I understand they switched to ball bearings from roller with the E83 items so I'd rather avoid swapping in the entire diff. Quote Share this post Link to post Share on other sites
