Differential & Axles

Stock Differential

R-Spec cars came with a Torsen limited-slip. Other trims may be open, so check yours before building around it.
2010–16 manual cars had a recall covering the rear differential and suspension crossmember bolts. Make sure it was done before adding LS torque.
The stock diff and axles are the usual weak point once you add power. Plan on axles first, then an 8.8 swap for big power.

Genesis Sedan Axles (Budget Upgrade)

Genesis sedan axles are a cheap, easy upgrade that should carry you safely into the 500–600 hp range. I broke a CV joint on one at 700 hp / 650 tq on the dyno, so launching at the track might not work.

Important: don't order the RH/LH-TAU V8 axles. You need the -LAM.

Side	Hyundai part	GSP part
Driver (left)	49600-3M000 LH-LAM	NCV37099
Passenger (right)	49650-3M000 RH-LAM	NCV37100

GSP NCV37099 rear left CV axle listing — GSP NCV37099 — driver/left.

GSP NCV37100 rear right CV axle listing — GSP NCV37100 — passenger/right.

Used Genesis sedan rear left axle listing — Used sedan axles are an option too.

Ford 8.8 IRS (High HP)

For builds targeting 1000+ hp, Jason Riddle's Ford 8.8 IRS kit is the documented path that avoids axle failures under hard launches. The kit replaces the stock differential and requires custom axles from The Driveshaft Shop (DSS).

DSS axle requirements: Send your wheel hubs so DSS can broach them from 30-spline to 33-spline. Measure seal-to-bearing (hub) carefully:

Driver side: ~23.25" (closer to 23-3/8")
Passenger side: ~24.25" (closer to 24-3/8")

Reference order (English Rob / Robert Kapeluch, DSS invoice 114850): Side A 23.5" Seal-to-BB, Side B 24.25" Seal-to-BB, 108mm-30 outer CVs with GKN grease caps. Customer sends OEM wheel hubs to be broached to 33-spline.

Install video: TikTok — Ford 8.8 IRS install