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MK diff into GQ - H233b
Posted: Mon Aug 06, 2007 10:22 pm
by Snarba
Hi there, I know there was a thread about this a while back but couldn't find it...anyway according to my manuals the rear diff of my MK ( with airlocker) is the same as the front and rear diffs in my GQ obviously with different ratios....does anyone know if they are swapable? it would be very handy for me if they are

Posted: Wed Aug 08, 2007 8:13 am
by Snarba
No one knows about this?
Posted: Wed Aug 08, 2007 9:16 pm
by 90Mav
Heh.. Its a nightmere ARB catalog lists:
RD04 for MQ H233 rear
RD24 for GQ/GQ H233 rear
RD 78A for GQ/GU H233 front
have no idea why this is so, or how and where the H233b or th MK comes into it..
Hope this confuses you as much as it does me...
Id check if the locker has a part number on it..
Posted: Wed Aug 08, 2007 9:57 pm
by Screwy
in a nut shell.......
MQ/MK rear diffs have the same spine counts as the GQ fronts do.
The mq and GQ rears and gq fronts are the same physical size but different spline counts between rears...
so basically,
You can bolt a gq front centre into a rear mq housing/axles and you can bolt a MQ rear centre into the front GQ housing/axle/CVs
But an MQ rear centre is not interchangeable in GQ rear housings.... or visa versa.....
rear to rear is a no go due to axle splines. you cant change the axles over because gq diffs are wider....
mq fronts are a completely different diff.
if you change the mq rear into a gq front you need to do a knuckle swap to bring the tie rod to the front of the diff instead of the back as gq fronts are high pinion and mq rears are low pinion....
also the gqs only have 4.1s, most mqs have 4.6s so you will need to ensure correct ratio changes.
screwy
Posted: Thu Aug 09, 2007 9:31 pm
by Snarba
Thanx Screwy

Posted: Sat Mar 29, 2008 3:04 pm
by WICKED
Ok About to do this to mine.... BUT...
The MQ H233b rear centre does not bolt in to the GQ Leaf front housing.
..................ANY BODY KNOW OR DONE THIS...................
The stud's are bigger, Can be fixed by drilling the 3rd member out to suit the GQ studs.
On the GQ Leaf housing there are 2 studs Approx 3/4 inch apart on the short side. MQ centre only have a single stud hole and it is ina different spot to the GQ one's. How can this be fixed? Weld the MQ 3rd Member hole over and drill a new one? Or remove stud's, weld over and re-tap a new stud in the housing?
I'm just worried that if we drill the holes in the 3rd member to be bigger and then drill a new hole for the other stud's that the Centre MAY not run true/Centre/sqaure? Is this a vaild point?
Any one that has been throught this before please give me a call on 0431 555 699. I'm at the shop now trying to sort this out.
Thanks all!
Posted: Sun Mar 30, 2008 11:10 am
by mikesmith
hi guys can you not just remove the rear air locker from the mq housing and fit it into the front gq housing or can it not work that way??
Posted: Mon Mar 31, 2008 7:42 am
by WICKED
Ok..... I spent saturday doin this. I've got a few pics but not on this computer.
NO, you can not just change the centre/3rd member over. With a bit of stuffing around, welding, grinding, tapping and other stuff you can get them to fit and work.
I'm useing a leaf housing so this maybe different. I also have a GQ Coil housing so i'll give it a go as well just to see. But won't be spending much time there.
Posted: Mon Mar 31, 2008 7:50 am
by RUFF
WICKED wrote:Ok About to do this to mine.... BUT...
The MQ H233b rear centre does not bolt in to the GQ Leaf front housing.
..................ANY BODY KNOW OR DONE THIS...................
The stud's are bigger, Can be fixed by drilling the 3rd member out to suit the GQ studs.
On the GQ Leaf housing there are 2 studs Approx 3/4 inch apart on the short side. MQ centre only have a single stud hole and it is ina different spot to the GQ one's. How can this be fixed? Weld the MQ 3rd Member hole over and drill a new one? Or remove stud's, weld over and re-tap a new stud in the housing?
I'm just worried that if we drill the holes in the 3rd member to be bigger and then drill a new hole for the other stud's that the Centre MAY not run true/Centre/sqaure? Is this a vaild point?
Any one that has been throught this before please give me a call on 0431 555 699. I'm at the shop now trying to sort this out.
Thanks all!
Ben drill and tap the housing to suit the MQ centre. Leave the old holes in the housing. Do not weld them up. You may eventually need them if you ever go to a HP GQ front.
Posted: Mon Mar 31, 2008 8:16 am
by WICKED
RUFF wrote:WICKED wrote:Ok About to do this to mine.... BUT...
The MQ H233b rear centre does not bolt in to the GQ Leaf front housing.
..................ANY BODY KNOW OR DONE THIS...................
The stud's are bigger, Can be fixed by drilling the 3rd member out to suit the GQ studs.
On the GQ Leaf housing there are 2 studs Approx 3/4 inch apart on the short side. MQ centre only have a single stud hole and it is ina different spot to the GQ one's. How can this be fixed? Weld the MQ 3rd Member hole over and drill a new one? Or remove stud's, weld over and re-tap a new stud in the housing?
I'm just worried that if we drill the holes in the 3rd member to be bigger and then drill a new hole for the other stud's that the Centre MAY not run true/Centre/sqaure? Is this a vaild point?
Any one that has been throught this before please give me a call on 0431 555 699. I'm at the shop now trying to sort this out.
Thanks all!
Ben drill and tap the housing to suit the MQ centre. Leave the old holes in the housing. Do not weld them up. You may eventually need them if you ever go to a HP GQ front.
the 2 (top and bottom) Holes closist the CW will need to be welded up and a new hole drilled and tapped and the GQ Stud and the MQ Hole/stud over lap a tiny bit.
Posted: Mon Mar 31, 2008 8:23 am
by RUFF
Ben dont do anything to it untill i come and have a look.
Posted: Mon Mar 31, 2008 8:28 am
by WICKED
RUFF wrote:Ben dont do anything to it untill i come and have a look.

Ok
Posted: Mon Mar 31, 2008 4:03 pm
by mikesmith
i dont mean the complete centre i mean remove the air locker hemisphere and fit it to the gq 3rd member??
Posted: Wed Apr 02, 2008 2:23 pm
by RUFF
WICKED wrote:the 2 (top and bottom) Holes closist the CW will need to be welded up and a new hole drilled and tapped and the GQ Stud and the MQ Hole/stud over lap a tiny bit.
Called in and had a look at this today. First you need to get a couple of grub screws and some lock tight. Lock tight the grub screws into the original holes. This must be done before you drill the new holes. And then very carefully drill and tap the new holes making sure you drill and tap these at 90* to suit the original MQ studs not the GQ studs. So the hole is slightly smaller than the GQ and doesnt end up as close to the original holes. Then lock tight the MQ studs into these holes.
This way if you ever want to fit the GQ HP centre all you need to do is remove the grub screws and fit grub screws back in where the MQ studs were.
The grub screws are important as the holes will be very close together and you will risk breaking through into each other if they are not fitted.
Posted: Wed Apr 02, 2008 2:28 pm
by RUFF
PS, That housing you cleaned is still filthy inside. Im not welding in grease

Posted: Wed Apr 02, 2008 2:42 pm
by WICKED
RUFF wrote:
... as the holes will be very close together and you will risk breaking through into each other if they are not fitted.
This was my major concern. One of the holes failing.
I think I've got the plate too, Double check tonight. It's thicker than we talk about though.
Thanks for that!
Lol its clean as!
Posted: Wed Apr 02, 2008 2:50 pm
by RUFF
WICKED wrote:RUFF wrote:
... as the holes will be very close together and you will risk breaking through into each other if they are not fitted.
This was my major concern. One of the holes failing.
I think I've got the plate too, Double check tonight. It's thicker than we talk about though.
Thanks for that!
Lol its clean as!
Thicker will be a PITA as i need to be able to form it to shape on the housing. 6mm Maximum, 4mm minimum please.
And if thats as clean as you can get the inside you better take a lesson in welding.
Posted: Wed Apr 02, 2008 3:03 pm
by WICKED
I saw your 6 and 4.

I thought that meant 10!
Lol I'll be there tonight for a little bit, I see what else I can do.
Posted: Wed Apr 02, 2008 10:38 pm
by BIG GQ
My bad Tony as I told him to weld the 2 holes then redill the 2 new ones but did not think about the fact that he may want to go to a GQ HP down the track hence needing the original holes.
MY BAD not Ben's
Posted: Thu Apr 03, 2008 8:14 am
by WICKED
Lol its all good Link. Thanks for the input too dude!
Gotta go on the hunt for some 4mm - 6mm plate

Posted: Thu Apr 03, 2008 1:57 pm
by bubs
WICKED wrote:
Gotta go on the hunt for some 4mm - 6mm plate

*Yawn*

Posted: Thu Apr 03, 2008 2:31 pm
by WICKED
bubs wrote:WICKED wrote:
Gotta go on the hunt for some 4mm - 6mm plate

*Yawn*

Tired mate?

Posted: Thu Apr 03, 2008 2:47 pm
by bubs
actually yes

Posted: Thu Apr 03, 2008 3:26 pm
by mikesmith
alrite guys so you got the centre to fit what other parts are you having to change on the diff to make this work?
all axles the same? driveshafts different bolt holes or all the same??
a run down on this would be good as i would be interested in doing this myself.