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The Datsun 1200 used a leaf-spring live axle with an H145 differential. This is a Hitachi design with 145mm ring gear (5.71 inch). It is a lightweight unit suitable to handle the torque from an A12 engine. Light weight is good, remember that heavy parts take more horsepower to accelerate. Some Australian-assembled B110s used a Borg Warner Model 60 rear axle. All Datsun 1200 utes (trucks) used the stronger H165 rear axle assembly.
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Differential
The Differential is the part in the center of the rear axle assembly. Also known as the "Gear carrier assembly", "pumpkin", "center" or "diff head". It has two purposes: 1) reduce the speed ("rear gearing") and 2) equalize power distribution to left and right wheels even when turning corners (differential).
The gear reduction is accomplished by the Ring & Pinion gearset a.k.a. (Crown Ring and Pinion (CRP). The differential action is enabled by the spider gears.
Specifications
Also see: Rear Suspension Specifications
- 3.90:1 ratio - sedans and coupes
- 4.11:1 ratio - VB110 wagons with aluminum gear case
- 4.11:1 ratio - B120 Truck
- Ring gear diameter: 145mm (5.71 inch)
- Torque Rating: about 100 lb. ft.
- Axle assembly width: 1305 mm drum-to-drum
Weight
- H145: 42kg
- H165: 52kg
Maintenance
The stock Datsun 1200 differential is a reliable, long lasting part behind an A12 or A13 engine.
- As long as it doesn't run dry on gear lube it will usually last forever. So check it every few months for signs of leaking.
- The only common maintenance is to pack the rear wheel bearings every two years or so. This will also keep the bearings quiet and reduce gear lube leakage into the brake area.
Differential Lubricant
Since the differential is a typical hypoid-gear unit, you can use any lubricant designed for such:
- the traditional "90 weight" gear oil
- the newer 75W-140 or 85W-140 multi-weight gear oil
For maximum fuel economy, use a modern multi-weight gear oil. Otherwise use this chart to select a single-weight oil:
1972 Nissan Specification * API GL-4 * MIL-L-2105
Such as: * Chevron Multiservice Gear Lub. 75,80,90,140 * Esso Gear Oil GP 80,90,140 * Mobil Mobilube EP or GX 80-90,90,140 * Shell Spirax 75EP,80EP,90EP,140EP * Sunoco Multipurpose Gear Lub. GL-4 80,90,140 * Texaco Universal Gear Lub. EP 80,90,140
1972 USA Owners manual (Page 23)
Recommended Lubricants
GL-4 vs GL-5
The differential can use a GL-4 oil, same as the transmission lube.
GL-5 is now recommmended for the differential, but should not be used in the gearbox unless it is marked both GL-4 AND GL-5.
Nissan 1981 Specification * API GL-5
Borg Warner Model 60
Australian-assembled B110s used a Borg Warner Model 60 rear axle, starting in Late 1971.
See main article: Borg Warner Differential
Leaf Spring Mounting
Sedan, Coupe, Wagon and Ute (Truck) all have different mounting points. See Leaf Springs
Swapping
Datsun 1200 Coupe, sedan, van, and ute housing are all just slightly different.
discussion in main forum
Sedan axle housing has no welded-on leaf perches. The others do. Plus other small differences.
Best Ratio for a Ute
The Datsun 1200 truck comes with a 4.11 ratio. This is excellent for acceleration, but some feel it is too low for highway driving. Rest assured, the A12 engine can run at 110 kph all day long even with the 4.11 gears.
Or you can change the gears. Read this dicussion: [url=http://datsun1200.com/modules/myalbum/photo.php?lid=3010]starting at Post 11[/url].
The Ute uses the H165 gears. See H165 for more information about ratios and donor cars.
Gear Sets
B110 - Datsun 1200 1971-1973 3.90 B110 Wagon 4.11
B10 - Datsun 1000 1967-1970 4.11 B10 wagon (VB10) with alloy carrier - 4.375
B210 - 1974 3.90 (north american)
Datsun Competition (later Nismo) used to sell various ratios: 3.9, 4.111, 4.375, 4.625 for the H145.
B10 Datsun 1000 H145 alloy carrier 38310-18000 COMP.-CARRIER, gear ALL * 38315-18000 STUD (fixing differential bearing cap) 4 ALL * 38317-18000 WASHER (fixing differential bearing cap) 4 ALL * 38318-18000 NUT (fixing differential bearing cap) 4 ALL
B10 Datsun 1000 H145 gear sets (will fit all Datsun 1200) 38100-18000 JDM SET-GEAR, hypoid with pinion (37 T: 9 T) [4.11] Sedan & Coupe 38100-H0700 JDM SET-GEAR, hypoid with pinion (35 T: 8 T) [4.375] Van * superceded 38100-18100 38100-15400 JDM SET-GEAR, hypoid with pinion (37 T: 8 T) [4.625] Truck 38100-G0400 JDM SET-GEAR, hypoid with pinion (37 T: 8 T) [4.625] Truck (from '69-Nov)
Datsun 1200 gear sets 38100-H1000 3.900 R&P SET Sedan & Coupe 38100-H1100 4.111 R&P SET Van
Datsun B120 (1200 Sunny Truck) gear sets - H165 (HC41) Type I carriers * 38100-28500 4.111 HYPOID GEAR & PINION SET (37/9) (to '72-12) * 38100-N5200 4.111 HYPOID GEAR & PINION SET (37/9) (from '73-1 to 7906) Type II carriers * 38100-W9000 4.111 GEAR SET-FINAL DRIVE 7907-8605 * 38100-G3300 4.111 GEAR SET-FINAL DRIVE 8605-
Differential Repair
Replacing diff bearings or spider gears? Or ring & pinion? The procedure for re-assembly the differential gear carrier is very complicated. Be sure to get the factory service manual.
We recommend: Just swap the whole center section "pumpkin" from a 1971-1973 B110 or 1974 B210 in there. It will be cheaper and certainly easier, someone has one for free. The center section rarely goes bad unless the diff runs low on oil, so your chances of getting a good used one are high.
Yes, B110 and 1974 B210 center section is identical. You could also swap a 1975-1978 pumpkin they say you need a 2mm spacer between the pumpkin and the housing.
Bumpers
Coupe & Van rear suspension bumper (above the Leaf Spring) 55240-H1400 ASSY-BUMPER REAR AXLE 08911-64010 NUT-HEX M10X1.25 08915-14010 WASHER-SPRING LOCK
Sedan rear suspension bumper (on the Shocks) 55240-H1001 BOUND BUMPER A 56124-H1001 BOUND-BUMPER B
Pinion Snubber
The pinion snubber is a rubber bumper that prevents the differential from rotating too much under torque input.
Part Numbers
Suppliers - USA
Axle
See Axle Shaft
Differential
Differential Side Bearing
O.D: 62mm
- 38440-H1000 ASSY-BEARING DIFF SIDE (2 needed)
- replaces 38440-18000 ASSY-BEARING DIFF SIDE
- HGM Liftparts, $9.36
- ebatmus.com $13 and up
- NSK HR30206J
- KOYO 30206JR
- NTN 30206
- SKF BR30206 O'Reillys/Schucks/Grand/Kragen $16.99
- National Bearing 30206
- BCA 30206 - $29.99
- Motor City S30206 - $9.88
- TIMKEN Part # 30206M - $14.96
- BCA/NATIONAL Part # 30206 - $16.74
Application:
- Alfa
- Mitsubishi
- Ford
- Mazda
- Nissan
- Plymouth
- Porsche
- Subaru
details
Specs:
Taper Bearing Assembly
O.D: 62mm (2.4409")
I.D: 30mm (1.1811 in.)
Width: 17.25mm
Pinion Seal
B110, through 1974 model year B210. Probably fits B10 as well.
- 38189-18000 SEAL-OIL DRIVE PINION
- SKF Oil Seal #550219 Partsamerica.com $22.99
Pinion Bearing
- 38120-18000 ASSY-BEARING DRIVE PINION REAR
- 38140-18000 ASSY-BEARING DRIVE PINION FRONT
Fits many cars, GM, Nissan, Isuzu, Mazda, Opel, etc
Taper Bearing Assembly: Cone Length=0.7874" Bore=1.1811" Outer Diameter=2.4409" Width=0.8366" Cup Length=0.6693" Cone Radius=0.06" Cup Radius=0.06"}
Rockauto
- BCA/NATIONAL Part # 32206 - $19.84
- SKF BR32206 - $18.99
- 38165-H1001 SPACER-DRIVE PINION BEARING $17.00
- 38154-G04xx WASHER-ADJUSTING DRIVE PINION $3.83 USD
Where xx = 00 through 17 for different thicknesses
- 38154-G0400 WASHER-ADJUSTING DRIVE PINION T=2.74
- 38154-G0401 WASHER-ADJUSTING DRIVE PINION T=2.77
- 38154-G0402 WASHER-ADJUSTING DRIVE PINION T=2.80
- 38154-G0403 WASHER-ADJUSTING DRIVE PINION T=2.83
- 38154-G0404 WASHER-ADJUSTING DRIVE PINION T=2.86
- 38154-G0405 WASHER-ADJUSTING DRIVE PINION T=2.89
- 38154-G0406 WASHER-ADJUSTING DRIVE PINION T=2.92
- 38154-G0407 WASHER-ADJUSTING DRIVE PINION T=2.95
- 38154-G0408 WASHER-ADJUSTING DRIVE PINION T=2.98
- 38154-G0409 WASHER-ADJUSTING DRIVE PINION T=3.01
- 38154-G0410 WASHER-ADJUSTING DRIVE PINION T=3.04
- 38154-G0411 WASHER-ADJUSTING DRIVE PINION T=3.07
- 38154-G0412 WASHER-ADJUSTING DRIVE PINION T=3.10
- 38154-G0413 WASHER-ADJUSTING DRIVE PINION T=3.13
- 38154-G0414 WASHER-ADJUSTING DRIVE PINION T=3.16
- 38154-G0415 WASHER-ADJUSTING DRIVE PINION T=3.19
- 38154-G0416 WASHER-ADJUSTING DRIVE PINION T=3.22
- 38154-G0417 WASHER-ADJUSTING DRIVE PINION T=3.25
Limited Slip
Datsun 1200 was not offered with a limited-slip differential, however Datsun Competition sold an LSD for the H145. This part is NLA, however it may be found occasionally in specialty shops or on eBay.
Nissan Competition
From the 1984 Nissan Competition Catalog
- H145A RING & PINION SET (TO 8/74)
- 38100-H1000 3.900 R&P SET
- 38100-H1100 4.111 R&P SET
- 38100-H0700 4.375 R&P SET
- 38100-G0400 4.625 R&P SET
- H145A DIFFERENTIAL ASSY
- The H145A 3rd members will fit the 1200 and B210 (to 8/74) and do not include limited slip units.
- 38300-H1000 3.900 3RD MEMBER
- 38300-H1100 4.111 3RD MEMBER
- 38300-H0700 4.375 3RD MEMBER
- 38300-G0500 4.625 3RD MEMBER