Drive Train Gearing Bible

[Runamuck]

hi I have 265/75 r16 mt about to get E lockers F&R what ratios is best for this set up ??

[packeteer]

hi I have 265/75 r16 mt about to get E lockers F&R what ratios is best for this set up ??

3.7's for manual or 3.9 for auto, unless you want lower gearing, in which case 3.9 and 4.1

that said, most people don't bother changing ratio for that size

[packeteer]

Secondly, i understand it's not ideal, but would going to a 3.7 make enough difference to offset the cost of having to buy another locker?

afaik, there would be no need to change locker for 3.7's (I used the same locker when I changed from 3.5 to 3.7)

[mchieff]

So I've read this thread briefly and as I've got 30.5" wheels on a petrol manual think I can just regear with auto diesel gears. I've found a rear carrier cheap locally but it doesn't seem to come with the pinion. Will I need the pinion as well (the missile bit not the giant ring) to get it happening or can I use my old one? Also what happens if I regear the rear diff but not the front then use 4wd? Will this cause any damage to the transfer case or can the planetary system handle the different speeds? Thanks in advance!

[calis101]

It probably not worth it for 30.5" tyres. But you front n rear need to be the same ratio or your transfer case will bind.
Id save your money n put it towards something else.

[packeteer]

as above, 30.5 is standard size tyre on SR5 since approx 2010 ie. no need to re-gear unless you go bigger.

I'd consider 3.7 ratio for anything up to 32" or 265/70/17

[mchieff]

Thanks guys, so both need to be done at the same time. Mines an 08 so did the petrol manual gearing change to accommodate the 30.5" tyres in 2010? Also I have 265/60r18 Cooper AT3s hopefully my googling was right that they are 30.5s but they looked bigger than a mates 2012 sr5 diesel auto

[VMN]

So I've read this thread briefly and as I've got 30.5" wheels on a petrol manual think I can just regear with auto diesel gears. I've found a rear carrier cheap locally but it doesn't seem to come with the pinion. Will I need the pinion as well (the missile bit not the giant ring) to get it happening or can I use my old one? Also what happens if I regear the rear diff but not the front then use 4wd? Will this cause any damage to the transfer case or can the planetary system handle the different speeds? Thanks in advance!

As said, you probably don't need to regear but if you do, the crown wheel and pinon are always machined as a matched set so you will need both. Then you won't need to buy a new rear carrier anyway....

[packeteer]

Thanks guys, so both need to be done at the same time. Mines an 08 so did the petrol manual gearing change to accommodate the 30.5" tyres in 2010? Also I have 265/60r18 Cooper AT3s hopefully my googling was right that they are 30.5s but they looked bigger than a mates 2012 sr5 diesel auto

yes, that size IS 30.5. Does you mate have the double cab? iirc the single/extra cabs may have different setups

there was no gearing change, but afaik there was a change in ecu programming which gave more torques

[mchieff]

Mates car is a double cab...

[packeteer]

by all counts, his vehicle should have shipped with 265/65/17 ie. 30.5

[mchieff]

Will have a look on the weekend

[Connor3.4]

What are you guys paying for gears and install? I got a quote from oppo lock for 4.5's fitted with all new bearings and stuff for 3500. They said the biggest cost is trying to set the back lash on the front

[packeteer]

wow, thats a lot of cash. I paid $1300. second hand gears and country mechanic

[Walker]

From what I read, the difference between the 3:7 front crown wheel and the 3:9 crown wheel is the deck hight. I can't find this mentioned in this thread but, is it possible to run the 3:9 crown wheel on the hilux front centre and run a spacer that makes up for the lost deck hight that the 3:7 has?

[Hilux Max]

the 3.7 and 3.9 crown gears are offset differently on the carriers.

it why Nitro make the "thick" cut 4.5 and 4.1 gears now, so you can run them in the standard 3.7 carrier.

Normal/factory 4.1 and 4.5 gears need a 3.9+ carrier to fit and work properly.


Re: running a spacer to make it work.....in theory this should be possible.

I think it was Skog or someone else a couple years back actually looked into it with ARB and from memory they could machine up something similar so you could use a higher gear with the standard locker but nothing ever eventuated.

[VMN]

What ARB told Skog was that if he was prepared to wait for the next Prado locker production run, they would make the replacement parts that would allow an existing 3.7 ratio locker to be rebuilt and converted to the 3.9 and up model.

[dan9245]

So i had a look on Just differentials and emailed the guys on there asking whats best for the manual TD 3.0 hilux... they told me this package which is front and rear was the go:
http://www.justdifferentials.com/GPFJCR ... lect-1.htm

Also fits straight into the Hilux carrier they said.
Sound pretty good?

[Hilux Max]

Whats the best?

How long is a piece of string?

Best for running 37's on a d4d manual and thats about it.

or 35's on a d4d auto.

You need to specify what tyre size you are running or want to run before deciding on which gear ratio is suitable to your needs. Just jumping in and buying gears and not knowing how it will change the dynamics of the vehicle is ludicrous.

So before asking for advice, please detail:

a) What transmission your running?
b) what tyre size you want to run?

and then email Matty@monsterrides.com.au as he deals with these gears and can hook you up.

[ONBAGZ]

I've booked the pup in for diff gears to suit my 33s and can run the 31s till I get 33s