16 replies to this topic

[WA1TNC]

G'day guys,

I recently brought a 2nd hand diff for my HX Ute which is a borg warner which I believe is out of a XA-XC fraud.

What's the best way to tell which type of diff it actually is because I want to upgrade it to a LSD, kaaz or put a lock-rite lokka in. & how do I tell whether its a 2 or 4 pinion & what spline?

Whoever did the conversion cut the tubes off a sailsbury & welded to the borg warner centre as it still runs the std drum brake set up. The axles haven't been re-drilled, they seem to suit the HQ pattern, my rims seem to fit fine & don't appear to be miss-aligned like a commodore pattern would be.

So is it just a case of pull an axle out & is there a way to check what spline it is by eye? As I hope they have somehow used the std 28 spline sailsbury axles & made it all work somehow & not just re-splined it down to a 25 spline to suit the centre if its a 25 spline centre.

Cheers, Nig.

[Uncle Chop Chop]

Count the splines, unless you don't have 28 fingers and toes.

[dattoman]

And pull the back cover off to tell whats in its guts

[76lxhatch]

If its an M75 its usally a pretty safe bet that two spider is 25 spline and four spider is 28 spline, so figure out one and you'll know the other. I'd say if you think they are Holden axles then the centre has probably been changed to four spider (they fit in the same hole).

[WA1TNC]

Sweet, so are you saying I can fit a bw78 centre in if I find one cheap enough as there more than likely to be 4 pinion? As long as I've got 28 spline axles?

So to check I literally just pull out the axle & count the number of teeth on the end correct?

I'm sick to death of the diff absolutely frying 1 wheel, whether I'm taking off in the wet or just putting the boot in to a lil bit to hard in the dry. Seriously in wet weather it's so bad, on & off the throttle constantly just trying to get her moving. Thanks guys,
Cheers, Nig.

[76lxhatch]

Yes the M75 two spider and four spider centres are completely interchangeable (with axle change). An M78 (which Commodores are not by the way, they are M75) has a different sized gear set but the carrier itself is still interchangeable into the same housing if you use the M75 gears.

Basically if it has 28 spline axles it will be a four spider centre.

Yes just pull the axle and count the splines.

[StephenSLR]

A 4 pinion design has 2 cross shafts and 4 spider gears as compared to a two pinion design that has only two spider or pinion gears.

 

A 4 pinion carrier is substantially more durable although they do not improve the actual performance of the vehicle.

 

 

 

 

s

Edited by StephenSLR, 12 July 2013 - 01:21 PM.

[WA1TNC]

Well I checked the splines & they are 28 spline which makes me happy.
I remember when the diff was out I ran a tape measure over it & the borg warner was about 10mm bigger from drum face to drum face.

So what are my options for an upgrade? I'd like to go LSD but I know they always wear out, of love a kaaz but it's a bit pricey so I'm leaning towards a lock-rite lokka now that I'm 90% sure it's a 4 pinion open wheeler.
Thoughts?

Cheers, Nig.

[76lxhatch]

LSDs do wear out, but they're fine for street-only use and you can run one reasonably tight. I have a 4WD Systems Lokka which works well, a bit noisy and requires the correct driving technique around tight/low speed corners but if you can put up with that they're great. If you want it smooth/quiet and refined then you're better off with a limited slip. Don't remember seeing a Tru-trac style mechanical LSD for these but could be a possibility?

[WA1TNC]

When you say you need to drive them the right way I know what you mean, but does it ever catch you out like a spool does as I used to have a welded up banjo in my LH & if you wer'nt paying attention you'd be in for a fright if you not ready.

Cheers, nig

[76lxhatch]

Not really, its more embarassing than anything else; if you come into a tight low-speed corner and don't get off and on the pedal smoothly then the diff locks up momentarily and you look a bit like a learner driver as it hops. At any time you have traction to both wheels and are accelerating or decelerating it will always unlock, if you only have traction to one tyre then it will have drive. At higher speeds you just forget its there. Some people ask me what the noise is when coming into a car park or something, I just tell them it needs new CV joints.

[WA1TNC]

Ok, but what about in the wet & going around corners? Does it act like a locked diff pretty much all the time or is it pretty forgiving? As I drive about 600+ k's a wk, mostly fwy but once I get off at Burke rd in the city it's propper stand still traffic.

[76lxhatch]

Depends entirely on the level of traction; that's what causes the diff to unlock. If both tyres have even halfway decent traction it will unlock. On a really greasy road I do notice a bit of slipping here and there, but its not caused by the diff - basically instead of spinning up one wheel like you would with an open diff, you instead get torque transferred to the other.

The unlocking action is caused purely by one wheel travelling faster than the other, you effectively only drive one wheel in a tight corner. It doesn't act like a locked diff until one tyre has lost traction.

[WA1TNC]

G'day guys, bit of an update.

I ended up stripping about 28 out of 40 something teeth off the crown wheel in the diff last week & rang around a few places to get some prices on a rebuild.

Luckily I picked up a complete pintara diff with 4.11:1 gears pretty cheap a few weeks ago.

Long story short, got diff rebuilt with all new bearings & the single pegger replaced with a nice tight rebuilt lsd centre. I just finished putting it all back together when I noticed that the axles can still move/slide in & out after everything has been tightened up which means that my wheels move also. I'd say they have about 4mm-6mm play in them......

Umm....so what's the deal with that as I haven't changed the axle bearings or changed how the axles or brakes bolt on????

I haven't driven it, just moved it off the stands out the way so I can get to my trailer to take down to the auto swap meet tomorrow.

Any help would be much appreciated.

Cheers, Nig.

[bryanw]

you have probably figured it out? but guess it has drum brake seals which are smaller than disc brake seals letting the wheels move.

[WA1TNC]

Yeah mate, it was the axle bearings were just rooted, I ended up getting new 1's put on, they we'r the right ones, just very shagged.

Cheers, Nig.