changing the gear ratio's in hilux diff.

[barned01]

hello
just a quick one, I am trying to hunt down a G series centre for my hilux rear diff conversion but have so far not been able to find the complete package.
I can either find a centre that isn't LSD but has the right ratio, or i can find an lsd centre in the wrong ratio, or it is lsd and the right ratio but in a completely different casing.
Now as i have never played with diffs before, i don't want to come across as sounding like a noob when asking for a bit of info from the people selling this gear.
so i have a couple of questions regarding the changing of parts for G series diff centres that i know some of you have been through.
The first and foremost would be: is this a backyard job to swap parts of diff centres or does it require that professional's touch.
more specific ones though:
2. how hard is it to change the ratio in a hilux diff. Assume i have a complete diff, lsd and all but the ratio is wrong so i hunt down the correct crown wheel and pinion, how hard is it to put this ratio in?
3. how hard is it to change to LSD. Assume i have the correct ratio diff this time but i found a LSD centre (4 pinion???) and want to replace the open wheel centre (4 or 2 pinion?????) that the diff currently is.
4. how hard is it to adapt parts from the supra/soarer xa7x/xZ2x into the hilux diff. Assume i have just a hilux diff, incorrect ratio and just open wheeler, but i have found a complete centre from a supra that is LSD and the correct ratio and i would like to put this tasty gear into my heavy paperweight hilux diff.

Which is the easiest to accomplish and the most cost effective, if labour is a necessity as it can't be done by backyard purposes then what sort of figures would i be looking at for each stepp (ball park estimate would be fine.)
Note it doesn't frighten me to pull a diff apart but i am just not sure if it has to be precision measured or not or things just slot together like a jigsaw.
cheers
Barnsey

[Big T]

I think the hardest part about puttting the diff back together is setting the backlash. Basically you have to make sure the ring/pinion are meshing together properly or you'll get premature wear and failure.

One way to do it is to get some paint (dunno if its a particular kind or not) and paint a section of the ring, put it back together and spin it a few times. The paint should be wearing evenly across the gears. If not, take it apart and repeat.

Eddie.

[ra_28]

Setting the heal and toe on the crown wheel is very important you set it to high up the gear you will get excess slop in the diff and will break alot sooner in to far on the gear the slop will be gone but there will be so much load from having no room to mesh it will also distroy gears. You can get a paint/grease its called marking blue thats what the experts use.. The best place for the meshing between the crown wheel and pinon is in the middle of the grear and a little towards the heal.

[YelloRolla]

Bolting the crown wheel to the LSD hemisphere is quite simple. As stated, the hard part is setting the crown wheel and pinion up in the carrier CORRECTLY.

The best way to see how to set the gears is to go to a library and get a book on it with lots of pictures explaining how it is done (most workshop manuals show what MARKINGS to look for on the BEARING BLUE). Getting bearing blue is easy (any engineers supply store), however the application (ie how thick/thin to spread it) comes with experience.

Definitely get pics and description though (maybe a quick google will turn something up), as trying to explain it here would be lime trying to teach someone how to drive with 4 lines of post in the forum (that is UNLIKELY). Better still would be to get some tradesman to teach you, then you ask all of the novice questions and be steered in the correct direction.

One of the main problems that you will encounter trying to set gears at home is having the necessary shims to set the crown wheel. The depth of the pinion (fore and aft) is set with a crush collar (get a new one to do the job too).

Hope that helps

[sideshow]

finding what u want is a hassle unless someone has already done it

[sideshow]

lsds are usually in 4wd diffs but they have short ratios like 4.3
late model hiluxs have 3.7 sometimes but they are open so finding what u want is a mix and match

i knew somoene that could use my orig 4.3 hilux centre on 4wds
and they had a 3.7 centre and they also had an lsd centre

so i swapped the 4.3 for the 3.7 and bought the 2nd hand lsd

then my old boss put the whole thing together and all i did was some wiring on a car of his
so a favour for a favour

so i got out of it cheap

u also have to make sure u it the correct pinion flange and everything has to be done correctly especially if they have colapsible spacers on the pinion bearings

if u dont know much then best pay someone

another tthing u can do is buy new set of gears from the usa they are abut 400 or so bucks in a wide variety of ratios

but just remember a diff could be like an engine rebuild its not cheap

i got quoted 2200 to get a custom holden diff made up in lsd and any ratio for my hilux

i got out of it for 100 bucks cause i hunted round and found right parts and knew right people

[brett_celicacoupe]

just buy a LSD centre (centre only) and then go out and buy the G series ratio you desire(dont need the centre this time - only the crown/pinion ). then take these items, plus the centre carrier, and go to your local reputable diff shop and say "here, make this all work properly "

might set you back a couple hundred bux but it will save you replacing things 12mnths down the track due to incorrect setup.

im usually keen to do/make things myself on my car but its not something ill be doing this time.

[wilbo666]

As already stated, there is a fair bit to setting up a diff (LSD or not).

You need to set the pinion height, pinion bearing preload (usually done with a collapsible, single use crush tube), backlash (the pinion height and backlash should adjust to give the correct wiping pattern) and the total preload/crown wheel bearing preload. The preloads are generally given in inch/pound (i.e. very small units which require a specialist gauge / torque wrench to measure).

It isn't really a back yard job unless you really know what you are doing IMHO. (ps I haven't ever got around to setting up a diff, however I have looked into it a little and it is something I am looking at doing in the near future ).

Cheers
Wilbo

[MacroP]

One of the main problems that you will encounter trying to set gears at home is having the necessary shims to set the crown wheel. The depth of the pinion (fore and aft) is set with a crush collar (get a new one to do the job too).

Hope that helps

Luckily for Hilux and Landcruiser diffs, is that they don't run shims on the carrier bearing, instead they run an adjustible(and lockable) nut on either side which makes for an easier setup. The pinion setup is the same though.

[barned01]

ok so i should really start with the shitty ole s series i have in the shed then and play with that and see if i can work that one out. thanks for the answers guys.
So what would then be the best of those 3 options then.
1. find the crown wheel and pinion to match a lsd centre (per brett's suggestion) (requiring machine shop to install the crown wheel and pinion),
2. find a lsd centre to match the correct crown wheel and pinion (if i am not adjusting or settinng the crown wheel and pinion does this mean i should be able to just change the centre at home or do i still need to play with the correct crown wheel and pinion),
3. go find a banger hilux casing and a supra lsd centre and say "machine shop work your magic" probably also requiring the most amount of labour.

[RT104GT]

just buy a LSD centre (centre only) and then go out and buy the G series ratio you desire(dont need the centre this time - only the crown/pinion ). then take these items, plus the centre carrier, and go to your local reputable diff shop and say "here, make this all work properly "

might set you back a couple hundred bux but it will save you replacing things 12mnths down the track due to incorrect setup.

im usually keen to do/make things myself on my car but its not something ill be doing this time.

Hey Brett, where can I get an LSD centre to convert the f 7.5 open diff I just got thanks.

[brett_celicacoupe]

MA61's are probly the most readily available source of cheaper ones.

its what im using at the moment and its pretty decent.


RA25's and also RA40 GT's have F series LSD but they are both rare as rocking horse shit.

if you have 600 to spare then buy a brand new truetrac torsen LSD.

do a search and youll find many threads about them. there is a distributer in sydney i think