3.55 Diff Ratio Crown Wheel and Pinion sets 76/78/79/100/105 and 80**
3.55 Diff Ratio Crown Wheel and Pinion sets 76/78/79/100/105 and 80**
Are They Strong Enough for My Landcruiser?
Yes! These gears have proven their strength in various installations, including Chris Hawkins' HDJ79 Landcruiser, which achieved an impressive 10.98 second ¼ mile time. Equipped with these diff gears, he managed to break two 4340 chrome moly axles during launches, affirming the durability of PDI gears.
Product Details
Order Includes:
This order comes with a front and rear set of crown wheel and pinion gears, complete with solid pinion spacers for both front and rear differentials.
Spacer Options:
Solid Spacer Kits: Includes shims for precise thickness adjustment.
Machinable Spacer: Requires machining to the correct length.
Recommended Applications
Suitable Models:
These diff ratio changes are recommended for manual transmission vehicles with performance upgrades, including:
VDJ76 / VDJ78 / VDJ79
HDJ100 / HZJ105 / HDJ105 (use VDJ79 bearing kit for front and rear)
HDJ79 / HDJ78 (use VDJ79 bearing kit for front and rear)
80 Series** (using 100/79 centre and 80 side gears in rear; front is a direct fit, use VDJ79 bearing kit)
Performance and Benefits
These gears have been installed in Landcruisers exceeding 300rwkw and 1000nm, showing excellent performance under heavy loads. Customers report that the 3.5 ratio provides an ideal balance for everyday driving, resulting in longer legs in every gear and reduced engine RPM on the highway.
Gear Ratio Comparison:
Standard VDJ79 ratio is 3.9; switching to 3.5 lowers engine RPM at 110kph by 250 RPM.
HDJ100 and HDJ79 with standard 4.1 ratios drop RPM at 100kph by 400 RPM.
Driving Experience:
With the upgraded gearing, 4th gear can now handle towing at 100kph, significantly improving highway driving comfort. In a HDJ79 with 180rwkw, the new gearing allowed for climbing steep hills in 5th gear comfortably.
Additional Considerations
Automatic Transmission:
The 3.9 ratio is recommended for automatic transmissions or if using 35-inch tires.
Torsen Centres:
Considering mechanical LSD Torsen centres can enhance power delivery on and off-road, while reducing stress on your drivetrain compared to locking diffs.
100 / 105 / 79 Series Install
These are direct fit into these models using the latest and strongest pinion spline count/design. That means you may need to buy a set of pinion flanges to get the best result possible.
80 Series Install
It is possible to use these gears in the front of the 80 series cruisers without cutting. To fit the 3.5 ratio diffs you will need a 100/79 carrier/centre/locker/elocker etc as the way the crown wheel mounts is very different, but they will have 32 spline drive to the axles. Your 80 series will have 30 spline so you won’t be able to install the axles without changing the side gears. This may require buying a second centre of the same type with the plan to change out the side gears.
We have 3.72 ratio crown wheel and pinion sets that are a direct fit to your 80 series so this will go together normally.
When installing these in a HDJ79/HDJ78 or 100 and 105 series the bearings and possibly the flange plate will need to upgraded as we are using the latest and strongest design.
From Motospecs the part numbers below will be useful
http://www.motospecs.com.au
DBK10 - rear (Japanese) bearings and seal kit set with gaskets - (approx AU$250)
DTDBK7L - front (Japanese) bearing and seal kit set with gaskets - (approx AU$260)
087-012492 - rear 32 spline flange plate (approx AU$80)
087-012495 - front 29 spline flange plate (approx AU$70)
