which diff(s) interchangeable for parts on GZ20?

[soar-ted Bruva]

hey guys, my lsd on my GZ20 needs a new crown wheel and pinion. Just wondering if anyone can tell me which diffs or from which cars will be be applicable for the parts to be interchangeable in to mine, ie any gz20 /ga70/Cresside diff? does it have to be a from lsd too or not neccessarily. Any certain guildlines or codes i need to make sure it'll have, to know the crown wheel and pinion from it can go into mine? And is the ratio of my diff related to the crown wheel and pinion or is that a seperate area so to speak

[Norbie]

Your GZ20 has a G-series diff, so you can use a crownwheel and pinion set from any other G series diff, whether LSD or not. This includes MkIII Supra, MX83 Cressida, and practically every Hilux since the dawn of time.

And yes, the number of teeth in the crownwheel and pinion set determines the diff ratio.

[brett_celicacoupe]

find one of the above mentioned cars and read the diff code off the compliance plate.

beside "TRANS/AXLE" is the gearbox and diff code, respectively.


yours will be something like "G315"

if you want the same ratio then find something with the same character at the front (G) and then the next 2 digits the same. the "31" in this case specifies the ratio.

the last digit is irrelevant since it tells you if its LSD or not.

norbie; your database seems to be not working...is this just me or...??

[Norbie]

The axle database has a new address:
http://toyotaaxle.norbie.net/

[soar-ted Bruva]

thanks guys for the response. So if i were looking to say wanna have a 3.9" diff i'd have to source a G series diff that already had this ratio would i? From what have gattered from various opinion a 3.9 or 4.1 would probably something i should look to run in my car, any thoughts?

[brett_celicacoupe]

MX83's are a good source for 3.9:1 ratio G series gearsets.

i sold a gearset of that description not to long ago for about $100

although there is plenty of importers down south from me so there might be lots of soarer stuff floating around

[CrUZida]

Just make sure you have G series first.

Povo spec 1G-GE Z20's sometimes had F-series diffs.

[soar-ted Bruva]

can't someone gimme a brief description of what kinda difference i would notice in performance and functuality of my car (not necessarily x revs @ x speed) between say a 3.9 and 4.1 diff? Thanks for responses, if anyone wants reps happy to give, just weren't sure anyone cared cos you all have hundreds

[CrUZida]

You'll barely notice a difference

[brett_celicacoupe]

3.9 would probably be slightly better since you have a 1JZGTE (??). the higher ratio helps to get the turbo spinning earlier.

i found a big difference going from 4.1 to 3.9 with the 1ggte. 1st gear actually became useful.

if you want to experience the difference for youself then put smaller wheels on the rear...this would let you feel what a 4.1 (or higher) ratio diff would be like.

[soar-ted Bruva]

ok, thats helpful. cheers

[cptsideways]

It's a lot easier to simpley get a complete diff unit from a Supra Mk3 MA70/GA70/JZA70 the GZ has quite a short diff, I've used a tall ratio LSD from an MA70 & it transformed the car the taller gears actually suit the cars better. Did'nt really notice any performance loss but a lot less gearchanging going on.

[soar-ted Bruva]

just wanna be clear, taller gears is higher or lower numbers?

[CrUZida]

Taller = Lower numbers

Taller = higher top speed

[soar-ted Bruva]

got it, student feels educated