Differential carriers, differential cases and front/rear differential assemblies · case material (ductile iron, ADI, cast steel, aluminium), ring gear size and ratio, axle rating, bearing preload and backlash, limited-slip and locking types, gear oil
A differential carrier is the housing assembly in a drive axle that holds the pinion, ring gear and differential case on their bearings; the differential case, bolted to the ring gear, carries the side and pinion gears that let the left and right wheels turn at different speeds. Front and rear differentials, and the inter-axle differential that splits torque between driven axles, use the same parts. Ask three things first: the case material and how it is cast and heat treated, the ring gear size, ratio and axle rating it must carry, and whether it is open, limited-slip or locking.
Differential carriers (carrier housings), differential cases and complete front and rear differential assemblies for cars, light trucks, heavy truck tandem axles and off-road machines, including limited-slip and locking versions and the inter-axle differential of a multi-axle or all-wheel-drive driveline (in brief). Ring and pinion gear sets sold alone, complete axle housings, transfer cases, half-shafts and differential gear oil are outside this page except where compared.
01
A 2018 open-access study in the Latin American Journal of Solids and Structures designed the austempering heat treatment of a ductile iron differential case for front-wheel-drive cars, originally made of as-cast ductile iron. It cites austempered ductile iron (ADI, ASTM A897M) at 900–1600 MPa tensile strength, 650–1300 MPa yield strength, 1–9% elongation and 269–512 HBW. The case iron was 3.4C-0.8Mn-0.03Cr-0.4Cu-2.3Si-Fe with 200 nodules/mm², and the selected cycle of austenitising at 950 °C and austempering at 330 °C gave a full ausferritic matrix; the paper notes the dimensional change from heat treatment must be allowed for before and after machining. [1]
A casting supplier's custom differential housing listing offers aluminium alloy, ductile iron, grey cast iron or cast steel, by casting, forging and CNC machining to drawings or samples, with casting tolerance CT12 and machining tolerance of ±0.01 mm. [4]
Dana's Spicer tandem axle manual shows how the carrier holds its bearings: the drive pinion runs on inner and outer bearing cups and cones whose preload is set by a spacer, checked as a rolling torque of 20–50 lb-in, with the pinion nut torqued to 800–1000 lb-ft (1084–1355 N·m); the differential case runs in threaded bearing cups adjusted to give preload, and ring gear backlash on new gearing is set at 0.20–0.46 mm. The carrier is bolted to the axle housing at 250–290 lb-ft (339–393 N·m). [2]
Editorial calculation: at 1 lb-in = 0.113 N·m, the 20–50 lb-in pinion rolling torque is about 2.3–5.6 N·m. [2]
Give the supplier the drawing or sample, vehicle or axle model, case and carrier material and grade (ductile iron, ADI, cast steel or aluminium), heat treatment, required mechanical properties and test method, casting tolerance and machining tolerances on bearing bores and flange faces, bearing sizes and fits, ring gear bolt pattern, surface treatment, inspection (dimensional, crack testing), and annual quantity.
02
Eaton's performance differential application guide (July 2022) selects a differential case by axle model, ring gear diameter, axle shaft diameter, spline count and ratio range. Examples: Dana 60 with a 9.75 in ring gear and 30-spline 1.31 in shafts, split at 4.10 and down versus 4.56 and up; GM 12-bolt car axle with an 8.875 in ring gear, split at 3.08–3.90 versus 4.10 and up; AAM 11.5 in for all ratios; and front-beam and front-independent axles listed separately from rear axles. [3]
The same guide describes four case types: Detroit Locker, an automatic locking differential that keeps both wheels driving; ELocker, an electrically selectable locker switched between open and locked; Detroit Truetrac, a helical-gear limited-slip differential; and Eaton Posi, a limited-slip with carbon friction discs, tunable spring-pack preload and a rebuildable design. Its oil guidance recommends a quality petroleum-mineral gear oil, with a lower-viscosity API GL-5 75W-90 equivalent in cold weather; for the Truetrac and Posi it specifies GL-5 rated 80W-90, with no friction modifier in the Truetrac because it reduces bias and a four-ounce bottle of friction modifier added to the Posi. [3]
In Dana's Spicer heavy tandem axles, capacity variations come from combining basic differential carrier assemblies with different axle housings, shafts and wheel equipment. The model code gives the gross axle weight rating in thousands of pounds (for example D46-170 and D60-190P), the gear type (single reduction, dual range, planetary double reduction, helical reduction) and options such as limited-slip, differential lock, controlled traction and a lube pump for the inter-axle differential. The driver-controlled wheel differential lock is air-operated to engage a curvic clutch between an axle shaft and the differential case hub and spring-released. [2]
Dana approves gear oils to MIL-L-2105E (API GL-5 for mineral oils), lists SAE grades by ambient temperature, for example 75W-90 for −40 to 38 °C and 85W-140 for −12 °C and above, sets mineral-oil change intervals of 120,000 miles or 1 year on line haul, and calls for standpipes to raise oil level where axle installation angles exceed 10°. [2]
Editorial calculation: the 46 in D46-170 is 46,000 lb of gross axle weight rating, about 46,000 × 0.4536 ≈ 20,900 kg. [2]
03
Jiangmen Letus lists housings for GAZ and UAZ vans alongside complete front and rear differentials; Shandong Prior lists machined housings for JCB, Mercedes-Benz, MAN, Scania and Meritor axles.
Listings range from custom-cast differential housings made to drawings, through machined housings for named truck and machinery axles, to complete front and rear differential assemblies for light trucks and vans. For an all-wheel-drive or multi-axle driveline, specify each differential separately: front, rear and the inter-axle (centre) differential, with any lock or limited-slip function.
04
| Part | Role | Fix in the order |
|---|---|---|
| Carrier housing | Holds pinion and case; bolts to the axle housing. [2] | Material, bolt pattern. |
| Differential case | Carries side and pinion gears; ductile iron or ADI. [1] [4] | Material, heat treatment. |
| Ring gear and pinion | Sets the ratio; backlash 0.20–0.46 mm in one manual. [2] [3] | Ratio, ring gear diameter. |
| Pinion bearings | Cups and cones; a spacer sets preload. [2] | Bearing set, preload. |
| Differential bearings | Threaded cups or shims set preload. [2] [3] | Adjuster type. |
| Side gears and axle splines | Spline count and shaft diameter fix fitment. [3] | Spline, shaft size. |
| Limited-slip or locker | Helical, clutch-disc, automatic or selectable locker. [3] [2] | Type, actuation. |
| Lubrication | GL-5 gear oil; pump for inter-axle differential. [2] [3] | Grade, capacity. |
05
None of the reviewed sources publishes bearing bores, flange pilot, bolt pattern or flatness, because these follow the axle; take them from your drawing or sample. The published values here are the case material, machining tolerance, ring gear sizes and oil temperature ranges. [4] [3] [2]
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Material grade | ADI 900–1600 MPa tensile; ductile iron, grey iron, cast steel or aluminium offered. [1] [4] | Grade, standard, test report. |
| Bearing bore diameter (mm) | Not stated in reviewed sources. | Bore sizes for your bearings. |
| Ring gear diameter (in) | e.g. 8.875, 9.75 or 11.5 in. [3] | Ring gear diameter, pinion offset. |
| Flange pilot diameter (mm) | Not stated in reviewed sources. | Pilot diameter, fit. |
| Bolt hole pattern (holes) | Not stated in reviewed sources. | Count, pitch circle. |
| Bolt hole diameter (mm) | Not stated in reviewed sources. | Diameter, thread. |
| Bearing bore tolerance | Machining ±0.01 mm offered by one caster. [4] | ISO fit class. |
| Flange face flatness (mm) | Not stated in reviewed sources. | Flatness on drawing. |
| Surface roughness (µm) | Not stated in reviewed sources. | Ra on sealing faces. |
| Operating temperature (°C) | Gear oil grades cover −40 to 38 °C (75W-90). [2] | Range, oil grade. |
| Weight (kg) | Not stated in reviewed sources. | Mass per part. |
| Torque capacity or axle rating | Not stated; heavy axles rated by GAWR in thousands of lb (D46-170). [2] | Rated input torque, GAWR. |
06
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Part: [carrier; case; front or rear assembly] Axle: [model; ring gear diameter; ratio; spline count] Rating: [GAWR; input torque] Material: [ductile iron; ADI; cast steel; aluminium; heat treatment] Traction: [open; limited-slip; locker; selectable] Machining: [bores; fits; flange flatness; Ra] Quantity: [units per year]
Jiangmen Letus lists differential housings and complete front and rear differential assemblies; Shandong Prior lists differential housings for named truck and machinery axles.
Lists differential housings for GAZ and UAZ 452 vehicles and front and rear differential assemblies for Toyota, KIA and GAZ models.
Product scope checked 2026-10-11
Lists differential housings for JCB, Mercedes-Benz, MAN, Scania and Meritor axles.
Product scope checked 2026-10-11
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Ductile iron, as-cast or austempered (ADI); a reviewed study cites ADI at 900–1600 MPa tensile strength, and a caster also offers grey iron, cast steel and aluminium. [1] [4]
Dana's Spicer tandem axle manual sets 0.20–0.46 mm for new gearing and says used gearing should be reset to its value at disassembly. [2]
Eaton calls for GL-5 80W-90 mineral gear oil; no friction modifier with the helical Truetrac, and added friction modifier with the clutch-type Posi. [3]
Sources checked 2026-10-12. Sources are an open-access materials study, a Dana Spicer axle service manual, an Eaton differential application guide and a casting supplier's product page; values for your part must come from the supplier's drawing, material certificates and tests.
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