BLOG CATEGORY · 17 ARTICLES
Performance & Upgrades
LSDs, lockers, gear ratios, axles and bushes: what each upgrade does, who it suits, and what we fit at Gearhead Diffs for street, track, towing and off road.
Upgrades · 18 August 2026 · 6 min read Best LSD for Street Use: Helical vs Clutch-Type LSD Helical or clutch-type LSD for the street? How each limited-slip diff works, the real pros and cons, and which is best for your daily driver. 
Upgrades · 4 August 2026 · 3 min read Axles, 28, 31 or 35 Spline: How Much Is Enough? 28, 31 or 35 spline axles for your Ford 9-inch or BorgWarner diff? Here's how spline count affects strength, and which one suits your build. 
Upgrades · 3 August 2026 · 10 min read Diff Upgrades NZ: LSDs, Lockers, Gear Ratios & Rebuilds Diff upgrades explained by our Christchurch specialists: LSDs, lockers, gear ratios and when a rebuild is your best chance to upgrade. 
Upgrades · 20 July 2026 · 8 min read Ford 9 Inch Diff Conversion for Holden HQ to WB Ford 9 inch diff conversion for HQ-WB Holdens: housing options, axles, gearing, brakes and pricing explained. 
How-To Guides · 19 June 2026 · 3 min read Solid Diff Bushes vs Rubber Diff Bushes Solid vs rubber diff bushes? Learn how each affects traction, wheel hop, driveline control, and overall vehicle performance. 
How-To Guides · 15 June 2026 · 3 min read Choosing the Right LSD or Diff Centre for Your Race Application Learn how to choose the right LSD or diff centre for your race application, circuit racing, drifting, rallying, drag racing, and time attack. 
How-To Guides · 5 June 2026 · 3 min read Why Your Differential Locker Won’t Engage Why Your Diff Locker Won't Engage. Learn the most common causes of locker failures, wiring and air supply issues to actuator. 
How-To Guides · 3 June 2026 · 5 min read Air Locker vs E-Locker: Which Is Better? Compare air lockers and E-lockers including how they work, reliability, maintenance, and off-road performance advantages. 
How-To Guides · 2 June 2026 · 3 min read Mechanical Lockers: How an Auto Locker Works Learn how mechanical auto lockers work, how they improve off-road traction, and the pros and cons of automatic locking differentials. 
Upgrades · 27 May 2026 · 2 min read Air Lockers: How They Work Discover how air lockers operate, their advantages for 4WD vehicles, and why they are one of the most popular off-road traction upgrades. 
How-To Guides · 22 May 2026 · 2 min read E-Lockers: How They Work What is an E-locker? Discover how electronic locking differentials work and the advantages they offer for off-road driving. 
How-To Guides · 18 May 2026 · 2 min read Diff Lockers: What They Are and How They Work What is a diff locker? Learn how diff lockers work, their advantages, and the differences between air, electronic, and auto lockers. 
Upgrades · 8 May 2026 · 3 min read Helical LSDs: How They Work and Their Pros & Cons Learn how helical LSDs work, their advantages and limitations, and why they are popular in modern performance and street vehicles. 
How-To Guides · 6 May 2026 · 4 min read Understanding 1 Way, 1.5 Way and 2 Way LSD’s Ramp rider LSD explained: how 1 way, 1.5 way and 2 way units behave on and off throttle, and which suits your vehicle. 
How-To Guides · 4 May 2026 · 3 min read Positraction LSD (Posi): How They Work Positraction LSDs explained, how they work, how they create traction, and how they compare to other LSD types. 
How-To Guides · 1 May 2026 · 3 min read Different Types of Clutch Type Limited Slip Differentials Clutch type LSD designs explained: Positraction, ramp rider, and factory units. How each works and which suits your setup. 
How-To Guides · 30 April 2026 · 3 min read Intro to Limited Slip Differentials A limited slip differential explained: how an LSD works, the main types, and why it matters for traction and performance on road and track. Other topics
Troubleshooting Diff noises, leaks, vibrations and failures explained: what the symptom usually means, what it costs to put right, and when a repair or an exchange diff is the better call. How-To Guides Plain English technical guides from the bench: how differentials, LSDs and lockers work, how to identify your diff, work out ratios and choose the right parts. Case Studies Real jobs from the workshop in Sydenham: what came in, what we found when we pulled it apart, and what it took to fix properly.