Regearing a Gen 3 is a third-member swap, not a gear set

DrivetrainCost$$$–$$$$Difficulty 5/5FitsGen 3

Anecdotal. This entry is not backed by factory documentation — treat its values and steps as a starting point, not as if they came from the factory manual.

Anecdótico. Esta entrada no se apoya en documentación de fábrica — tome los valores y los pasos como punto de partida, no como si vinieran del manual de fábrica.

The route to a different final drive that anyone has actually documented on this generation is not a new gear set: it is fitting the differentials from a truck that left the factory geared shorter, which is the job the video cited below walks through end to end. Read the rest of this entry knowing that its evidence is thin and that its two sources disagree. The video, writing about the US market, says the 2001-2002 XLS is the model that carries the shorter gearing and that everything else from 2001-2006 does not; the forum list, covering the Pajero/Montero range globally, gives the same SOHC V6 engines one ratio with no such carve-out. Both figures are quoted in the citations. Neither source states what actually distinguishes one truck from another, and neither addresses whether differentials from the early cars interchange with the later ones — which is the premise the whole donor-swap idea rests on. Verify against your own two trucks before any money moves.

What it needs first

Nothing else has to be done first.

What it breaks or affects

Everything below is a consequence of fitting this, not a reason against it. Read it before you buy, not after.

System	Consequence	What happens
Drivetrain	Has to be reset	This one is our reasoning rather than a quotation, because neither cited source discusses front-and-rear pairing at all — they give ratios per engine and gearbox and stop there. The reasoning: a Gen 3 drives all four wheels through a centre differential, so front and rear must turn at compatible speeds, and leaving one axle on a different ratio from the other would load that centre differential continuously rather than only in a turn. That is why the job is always described and priced as a pair of third members. Have a differential shop confirm it for your specific drivetrain before you buy one end.
Interior and trim	Has to be reset	A differential ratio change moves the speedometer in the opposite direction to a tire change, so if you are correcting for 33s the instrument error shrinks rather than grows. It is very unlikely to cancel exactly: check what the cluster reads afterwards against a known-good reference before you trust it, and read this together with the linked tire entry.Modificationgen3-wheels-tires-33-inch-tires
Engine	Gets worse	Shorter gearing means more engine revolutions for the same road speed, permanently and in every gear. That is the whole point off-road and the whole cost on the highway; it also means the engine spends its life in a different part of the rev range than the factory chose for it.

The honest tradeoffs

This is expensive work and, in practice, close to irreversible, because you are buying and fitting two complete differentials rather than adjusting anything. Start with the part this entry cannot answer for you: confirm the ratio actually stamped on or tagged to the donor differentials and on your own, rather than inferring it from a model year, and confirm with the seller or a differential shop that the donor units physically interchange with yours across the years involved. Our sources disagree about which trucks carry what, and say nothing at all about interchange, so treat both as questions to close before purchase and not as facts this page has established. Both ends then have to end up on the same ratio. Donor parts are used parts with an unknown history, and a differential that arrives quiet can still be a bearing away from being loud. On the other side of the ledger, the shorter gearing raises engine speed at every road speed for the life of the truck: better pull and better low range, worse cruising revs and no fuel saving, and on a 33-inch tire it does not simply restore the factory feel — it goes past it, which some owners want and some regret. If the truck is not going to run tires much larger than 33 inches, weigh doing nothing: the gearing loss from a 33 is real but modest, and it is a smaller number than the cost of two third members. Driveline work of this size belongs with a qualified mechanic; a differential set up wrong is a roadside failure, not a rattle.

What it needs first

What it breaks or affects

The honest tradeoffs

Sources