long shot... info on GX71 "G-series" diff.... what can i do ?

[Admiral coFF33]

hey all , been a while since i posted in here.

After making my 1ggte cresta (GX71) manual, the W58 from an A70 is quite a short ratio and so is the automatic 4.5 ratio diff i have in the rear end.

This causes 1st gear to be completely useless and 100kph @ 4200 RPM ...

After removing the diff and almost swapping with Mullet from Toymods, we figured out that my diff, although looking exactly like an F-series from a MA61, is actually a G-series in some sort of weird f-Series housing....

what i mean is , that the bolt in pattern is identical to a MA61/MX73 diff , but the axels and tailshaft flange is a larger PCD, meaning i cant simply bolt in a ma61 3.9 ratio Fseries. ...

From what ive read on the USA cressida forums and here, this diff i have is really F@#King rare. So im kinda stuck with what i could possibly do to change the ratio in the rear end.

Would it be possible to find a low ratio Gseries from a GZ20/A70 and put that centre into my Hybrid F/Gseries ?
Does ANYTHING else come with this diff?

ive had suggestions from some, to swap in a complete rear subframe from an MX73, but thats difficult as i cant find anyone wrecking a complete MX73 anywhere, and they are getting rare'er over here in perth...

Ideas ?

charrrz
coFF

[JDM-20L]

Aren't G series same as Hilux? use the Crown wheel and pinion from there?

If it helps or not..

The GZ10 Im parting.. the whole rear end would suit wouldn't it? (not sure of ratios but MZ12 had 3.58)

I'm sending Andrew (cruz) some bits this week maybe you could consolidate freight and save $$$

[Admiral coFF33]

if you have a MZ12 diff. Its most likely EXACTLY what i need.
and i will pay lots of money if you do.

[CrUZida]

MZ12 diffs are identical to MA61/MX73 diffs, except that the input flange is a G-series flange. Everything else is the same.

[JDM-20L]

AFAIK the F series in the MZ12 had a G series tails haft flange, only MZ12 manual had a G series... fucking uber rare!

I'm not parting with my MZ12 diff no.

But if the GZ10 stuff is any help just shout out.

[CrUZida]

And I think its only the GT Limited MZ12's that had the G-series flange.
I'm fairly certain my MZ21 GT was just a normal F-series.

[Admiral coFF33]

Ok so plan is (Matt Capp MATTAE86 Plan)

Get a G series from Z20/A70/MX83

Pull apart G Series, Obtain Crown and Pinion.


Get Cresta Diff.

Pull apart, Swap Crown and Pinion with other diff, but KEEP the centre as the original GX71 centre, so the Axels spline in as per original spec.


So with a lower ratio Crown and Pinion i SHOULD get a lower ratio but inside the original diff.

Obviously id need to replace the crush tube aswel. So i guess i need to find one for a MX83 (G series) Diff ? seeing as my current diff is a G series ?

[wilbo666]

And I think its only the GT Limited MZ12's that had the G-series flange.
I'm fairly certain my MZ12 GT was just a normal F-series.

My understanding is the following...

MZ12 Auto = F series with G series input flange (Pretty sure it didn't matter if it was a GT or GT LTD)
MZ12 Manual = G series (This is according to the EPC as I've never seen one or even heard of one...) --> As a note this part number cross references to GX71


Short answer is that MZ12 auto won't be the direct bolt in fit you are looking for I don't believe and you might as well try and find rocking horse S@#$ if you think you'll find a MZ12 manual diff around (IMHO)


Also your plan will most probably work, but I'd spend a little bit of extra time up front finding out the part number of your original ring gear and crown wheel (use your frame number and www.toyodiy.com would be my suggestion), and then cross reference that to see if it's the same as Z20/A70/MX8x (Z2x and A7x in particular came in a wide range of diff ratios)...

Another option would be to pull your current diff apart and check the part numbers (Tho it's been a while since I've pulled apart a diff and I don't even recall if the part numbers are marked on the ring and pinion... tho one would think they should be!)


Personally if it was me I'd look at putting in a whole xZ1x or MX73 conventional F series rear end - suspect it will be cheaper overall and also much easier to find a diff for if you need one in the future (FYI I've never confirmed that xZ1x is the same as MX73, but I believe it to be.)

Cheers
Wilbo

[JP85MX73]

What was the diff code on the cars vin plate? If its a G you can just interchange any G series R&P. Are the mounting points actually the same as the x7 f series (I dont believe they are)? Ive been looking for this diff for a long time to handle my x7s power but they are hard to find. Could you put up a pic of what the pumpkin looks like? and let me know if you want to sell it, id kill for this diff if it works.. Ill probably end up buying an entire gx71 gt.. if i can find one.

This is the x7 pumpkin

[Admiral coFF33]

My car does not have a vin plate.
(yeah, it really doesnt)

Its the GX71 GT Twin Turbo 1GGTE model.

Thats above looks like a MX73 Pumpkin.... (fseries) mine has more cooling fins on top near the hanger and underneith. And of course a tad larger to house the Gseries gear.

Im ripping it apart wednesday and changing over the R&P to MA71 3.7/3.9

Just bought a new crush tube from toyota.

fingers crossed

[Admiral coFF33]

They are not SPOT ON SIDE BY SIDE. which makes the GX71 diff look a tad longer and the hanger in a further back location
but infact they are the same.

GX71 on left,
MA61 on right,

[wilbo666]

They are not SPOT ON SIDE BY SIDE. which makes the GX71 diff look a tad longer and the hanger in a further back location
but infact they are the same.

GX71 on left,
MA61 on right,

So you are saying that the G series from GX71 would bolt into MA61, and only the tailshaft flange and the drive shaft lengths would be incorrect?

Cheers
Wilbo

[JP85MX73]

I always thought gx71 8" diffs had 5 studs on the arm instead of 4? If they are bolt in i really need to get my hands on one of these in the US somehow. I already have broken my f series with a true trac and a solid pinion spacer....

[Admiral coFF33]

So you are saying that the G series from GX71 would bolt into MA61, and only the tailshaft flange and the drive shaft lengths would be incorrect?

Cheers
Wilbo

Id say yes,
using a MA61 hanger (the gx71 one is taller)
however the front right topside bolt hole (closeset to the tailshaft flange) is a TAD lower than the MA61 one.
And yes, the flange PCD and the Axel PCD and the driveshafts would be the issues.

so all in all.

"bolt in "

would be the wrong way to say that the GX71 diff , with a bit of effort, can fit into a MA61.

[mullett]

Dude...Swap driveshafts. Make input flange adaptor (this is seriously easy...give me an hour or so with both diffs )

Install standard F series.

Profit.

Changing the internals requires resetting the pinion and a bunch of other hassle...and that's *assuming* that the standard G series stuff is the same.