GQ/GU Patrol Rear Diff Conversion Guide – N70 Hilux

GQ/GU Patrol Rear Diff Conversion Guide – N70 Hilux

A basic write-up for anyone looking to convert their N70 Hilux to run a Nissan Patrol GQ (or GU) rear diff. This is an H233B rear housing from a GQ, but the same process applies to a GU diff.

Flange

Use a rear RB30 GQ flange — this is also the front flange fitment across many Patrol models (see part reference below). Patrol centres don't use a crush spacer like the Hilux, so you can undo the nut, swap the flange, and do it back up without drama.

Part No. 38210-01J01 — H233 Front Diff Pinion Flange for Nissan Patrol GQ Y60 and GU Y61:

  • Suits GQ front diff: TB42S, TB42E, RB30S, TD42
  • Suits GQ rear diff: RB30S, RD28T
  • Suits GU front diff: RD28T, RD28TI, TB45E, TB48DE, TD42, TD42T, TD42TI, ZD30DDTI
  • Suits GU rear diff: RD28T, RD28TI, ZD30DDTI

Brake lines

All fittings are the same, so the GQ hardlines can be reused on the diff — just swap sides, since the tee on Hilux setups is on the passenger side. Fresh rotors and calipers are cheap (around $180 on eBay) and worth doing while you're in there.

Springs

Leaf springs are the simplest option if this is a daily — it avoids sourcing an expensive Hilux housing. Factory Hilux U-bolts and shock mounts can be reused.

Perch spacing

The axle-to-pinion-flange length is approximately 20mm more on the Patrol diff than the Hilux diff. To account for this, the diff needs to be spaced back — this means drilling the locating pin holes on the leaf perches 20mm forward of stock. We sell a pre-made weld-on leaf perch kit that has this offset already built in, so you don't need to drill your own.

ABS

Currently a lost cause on this conversion — no workaround yet, though it's technically possible with more work.

Brake bias valve

Cut the perch off a Hilux diff and weld it onto the Patrol diff, then adjust the bias valve accordingly.

Handbrake

First-gear low range can be used as a handbrake substitute in the interim.

Bump stops

Stock Hilux bump stop mounting plates don't line up properly with the Patrol housing. As a temporary fix, hook the bump stop under one U-bolt for on-road use.

Result

With the Patrol diff and disc brake conversion, all four 315/75R16 tyres lock up easily on dry bitumen — a big step up from stock Hilux drum brakes.

This is a weld-on conversion — welding is required to fit the leaf perches correctly. Not a bolt-on kit.

Shop the kit: GQ/GU Patrol Rear Diff Weld-On Leaf Perch Kit

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