Tranfer box or diff ratio change to bring down rpm

[Toyotaprado120gx Lurker Find all posts View Profile Close Toyotaprado120gx]

Hi i was wondering if i could change the gear ratios in my diff or tranfer box to bring down my rpm @ 100km im doing around 2400rpm and what the best to change 1st i was thinking tranfer box

[ejukated Senior Member Find all posts View Profile Close ejukated]

what engine/gearbox?

[Toyotaprado120gx Lurker Find all posts View Profile Close Toyotaprado120gx]

Sorry its a 3.0ltr turbo diesel 5 speed box

[raydes Advanced Member Find all posts View Profile Close raydes]

100km im doing around 2400rpm ???? what gear are you in ? 3rd??. lol. some bigger tyres will bring it down a lot easier than changing diffs or transfer gears.

[Toyotaprado120gx Lurker Find all posts View Profile Close Toyotaprado120gx]

Yeah i thought was strange myself but thats what its doing in 5th @100km its running the standard 225/70 17" wheels

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Ok, the earlier ran these which are a 29.5" tyre. Does your tyre placard also show 265/65 17 on 7.5" rims as an option? If so you can go up to 265/70 17 which will drop you revs at 100 down to around 2,000 rpm (these are a 32" tyre) as long as WA regulations have been updated with the rest of the country. Otherwise you can only go +50mm (again if the regs have been revised) that will limit you to 265/65 17 and about 2,100 rpm from memory. You can likely pick up some GXZl alloys or later model GX steel wheels which will run those tyres. But.... And this may be an issue... Your tyres will sit just past the guards without the plastic flares. Plenty have done this without being arrested upon by the police or department against transport.

Changing diff ratios will be more that tyres and rims and I am not sure what ratios you are running standard.

[ejukated Senior Member Find all posts View Profile Close ejukated]

Sorry its a 3.0ltr turbo diesel 5 speed box

There is a mod to have a lower ratio overdrive in 5th, partial box rebuild tho

[Toyotaprado120gx Lurker Find all posts View Profile Close Toyotaprado120gx]

Hey fellas thanks for the help i was thinking of putting bigger wheels on 265/70 17" is the biggest as of wa rules 50mm over or under standard which sucks but owell

[Nova Member Find all posts View Profile Close Nova]

Not 100% sure of the WA rules, but don't they take the largest size on the tyre placard as the baseline, not specifically what the car was delivered with?

Cheers, Nova