First question is “Are the strong enough to consider fitting into my Landcruiser?”

Yes - from all installs they have proven themselves and are when fitted to Chris Hawkins HDJ79 Landcruiser which has done a 10.98sec ¼ mile. With these diff gears fitted he has managed to break two 4340 chrome moly axles when launching. “Can say the PDI gears are pretty bloody good now mate”

This order is for a front and rear set together. These crown wheel and pinion sets come with solid pinion spacers for front and rear diffs. Our solid spacer kits come with shims to get the correct thickness or you can select a machinable spacer without shims that will need to machined to the correct length.

The diff ratio change is recommended for those with a manual transmission and performance upgrades in the following models

VDJ76 / VDJ78 / VDJ79

HDJ100 / HZJ105 / HDJ105 manual transmission - use VDJ79 bearing kit (front and rear)

HDJ79 / HDJ78 - use VDJ79 bearing kit (front and rear)

80 series** using 100/79 centre and 80 side gears in rear. Front is a direct fit. Use VDJ79 bearing kit (front and rear).

These have been installed and tested in a number of Landcruisers boasting in excess of 300rwkw and 1000nm. They have shown to be more than capable of the task and perform very well.

Customers have reported the 3.5 ratio gives the ideal ratio for normal driving with longer legs in every gear and lower revs on the highway. Compare this to the “5th gear ratio change”, which maintains other gear ratios (unless also changing 2nd gear) where you will find them still revving too hard in other gears and short changes being require since they are so close together. The 5th gear change may be more suited if you are regularly pulling a heavy load (greater than 2.5-3T) and have to take off up hills as you will need to slip the clutch more in this situation, unless able to slide into low range for these occasions.

The VDJ79 have standard ratios of 3.9 so changing to our 3.5 will drop your engine rpm in 5th gear at 110kph by 250rpm.

The HDJ100 and HDJ79 have standard 4.1 ratio gears so these will drop your rpm at 100kph by 400rpm. It means 4th gear can now do what 5th gear used to do. Towing is much more acceptable in 4th gear at 100kph.

In a HDJ79 with 180rwkw we found that we could still climb (and accelerate up) a reasonably steep hill in a 50kph zone in 5th gear. This showed that the gearing needed attention and even with 3.9 ratio gears this was still possible. With the 3.5 gears we needed 4th gear and now we had a gear that was perfectly suited to highway driving.

We suggest the 3.9 ratio is a better option for automatic transmission or if running 35in tyres.

Also worth considering is the mechanical LSD Torsen centres, which make the power delivery much better on and off road, while place less stress on your drivetrain than locking diffs.