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View listing at Treasure Coast Miata; opens in a new tabMiata · Buyer's guide
Miata Differential, Axles & Torsen Swap
NA/NB Miata / MX-5 1989-2005
Current seller options
WHERE TO BUY
Open an exact listing, then confirm fitment, stock, price, and shipping with the seller before ordering.
Seller links checked . Prices and availability can change.
NA/NBSeller listing
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View listing at Planet Miata; opens in a new tabNA/NBSeller listing
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View listing at Mike's Miata Parts; opens in a new tabNA/NBSeller listing
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View listing at Planet Miata; opens in a new tabWhat you need to know
Gate 1 verified as an interchange page. 1990-93 1.6 cars use the smaller/fragile 1.6 rear end; swapping to a 1994-2005 1.8/Torsen setup requires the complete 1.8 diff housing/assembly plus matching 1.8 axles/half-shafts and driveshaft. Do not tell buyers to mix 1.6 driveshaft/axles with 1.8 diff. For 1994+ 1.8 cars, Torsen/open swaps are closer to diff-only if the existing 1.8 axles/driveshaft match. Ratio matters: 4.10, 4.30, 3.90, 3.63 show up and sellers misuse 'Torsen' loosely.
OEM numbers
Interchange page. New Torsen II center MM03-27-200 fits 1994-2005 1.8L differential assemblies but requires bearings and differential setup. A 1990-1993 1.6-to-1.8 conversion requires the 1.8 differential/housing, matching CV axles and matching driveshaftratio and Torsen type must be identified.Supersession
No supersession. The safe path is a verified complete conversion or a professionally set-up center section. Ratio, 1.6/1.8 hardware and included housing/axles/driveshaft matter.
Fitment
Gate 1 verified as an interchange page. 1990-93 1.6 cars use the smaller/fragile 1.6 rear end; swapping to a 1994-2005 1.8/Torsen setup requires the complete 1.8 diff housing/assembly plus matching 1.8 axles/half-shafts and driveshaft. Do not tell buyers to mix 1.6 driveshaft/axles with 1.8 diff. For 1994+ 1.8 cars, Torsen/open swaps are closer to diff-only if the existing 1.8 axles/driveshaft match. Ratio matters: 4.10, 4.30, 3.90, 3.63 show up and sellers misuse 'Torsen' loosely.
Aftermarket options
Checked new MM03-27-200 center, used complete Torsen differential, complete early-car conversion pricing and professionally blueprinted differential path. Mikes complete 1.6-to-1.8 kits were sold out. Bare-center installation requires bearings, preload and backlash setup.
Before you buy
A 1990-1993 1.6 car needs matching 1.8 differential/housing, axles and driveshaft. Confirm ratio, Torsen type, included parts and condition. A bare MM03-27-200 center requires professional bearing, preload and backlash setup.
Research and fitment sources
Supersede reviewed 8 unique research sources for this guide. 4 also appear above as a seller or official action and are not repeated here; 4 additional citations follow.
Research last verified .