Q's about LSD

[callan_rs2000]

as you may have seen on the forum i have been chasing an LSD

i have a couple of questions as i have no experience with them

what would be making a 'clunking' noise off throttle?
is the crown wheel, pinion, axles, etc all interchangable between open diffs and lsds?
estimates on costs for getting a used one rebuilt?
my car is a JA, does that mean only up to JB lsds will fit?

thanks

[Alspos]

as you may have seen on the forum i have been chasing an LSD

i have a couple of questions as i have no experience with them

what would be making a 'clunking' noise off throttle?
is the crown wheel, pinion, axles, etc all interchangable between open diffs and lsds?
estimates on costs for getting a used one rebuilt?
my car is a JA, does that mean only up to JB lsds will fit?

thanks

Clunking could be from a number of sources...the splines in the torque tube may be worn which is giving you a little movement and noise, half shaft unis could be worn and clunking, tailshaft uni could be worn and clunking and then there is excess backlash inside the diff itself. The unis and torque tube are easy enough to check, inside the diff is obviously a little harder.

A little history for you, JA's and some early JB's have a small diff housing...a few had LSD but most were open. Later JB's and all JD's have a large diff housing, some had LSD's in them. The difference in the diffs is the small diff housing has a longer torque tube and vice versa, the big diff housing has a shorter torque tube, they are not interchangeable.

The half shafts work in both diffs.

The innards of the diffs are not interchangeable from what I know, large diffs' crownwheel is slightly wider which I assume would mean the pinion gear is also wider. Then the larger crownwheel won't fit inside a small diff housing.

Costs to rebuild...dunno.

Now someone will chime in here and say 88-89 diff from the US will fit. Correct, it will bolt into the same spot in the car, but it requires half shafts from that diff then some surgery to make them bolt up to the standard axles...or replace them with US ones also...depends how deep your pockets are.

Not sure if anyone has done this exercise but I can see no reason why you couldn't just buy an LSD centre and install it in your current diff. Like this perhaps? but this one is from an 89, so bigger half shafts are needed etc.

I don't know if an aftermarket one exists....surely someone like Kaaz or whoever could make one if it didn't already exist. I think you'd need to know the dimensions of the centre and the size/PCD of the mounting holes.

Hope this helps.

[OLD FART]

Can be a number of things :(
Worn uni joints
worn torque tube splines
Too much backlash in the diff
Diff or TT mounts worn

[callan_rs2000]

so in theory i could take out the JB lsd centre and put it in my open diff? if its not as worn on any teeth on any of the gears/pinions/wheels or whatever, then there should be no clunking or free play and i should have a working lsd?

[Alspos]

I would think so, yes..... Assuming the diff housings are the same. Even if they are not, my guess would be that Mitsubishi in their wisdom wouldn't have developed different diff centres for small and large diffs, only the crownwheels and pinion would differ. Someone who has done it should be able to chime in here I hope.

I would open them both up and see what you can measure. The width from bearing to bearing, the distance from bolt to bolt and the overall diameter of the centre. I reckon it will fit straight in.

[redzone]

You cannot fit an lsd from a big diff ie 88/89 to a small diff as the crown wheel is a different diameter.

Yes you can pull the lsd from a small diff & instal it into another small diff.

Very very very very very few JB's had the big diff, I have worked on quite a few jb's and all of them have had the small diff fitted oem, and that includes the second highest chassis number car on the registry...

[ProZac]

Does anyone know the specifics on the inner CV splines?

I remember ages ago having a look at fitting an 1984 L200 LSD diff head into a small starion diff housing, was a no-go due to crown-wheels and pinion sizes. I have a sneaky suspicion that it would have fit into a later starion 'big' diff housing though.

Also, the inner axle splines were much larger on the L200 head than the early small starion CV's.

I have another sneaky suspicion that the later model 6-bolt american axles have bigger splines, that might match up to that L200 diff head however. I have no solid data on this though.

Still easiest to get a complete widebody rear end and swap it in, cross members, diff, axles, hubs, the whole lot. Spendy though.

[Xentro]

I actually tried a l200 diff (but i don't know the year/model it came from)

in short... splines don't match.

http://www.turbogarage.nl/2009/07/stari ... ntial.html

[callan_rs2000]

so what do people think? is it worth buying a second hand lsd and putting the centre in one of my open diffs? or welding up one of my open diffs instead? its for a dedicated track car too, no street duty at all!

what is the general consensus?

thanks for everyone's input and help

[panda]

My son runs a Sigma track car & has tried open & LSD diffs, but the best, and cheapest, and most reliable was a 'mini'spool' fully locked diff. Not sure if you can get a mini-spool for a Starion diff tho.

[redzone]

Craig's group a starion runs a normal lsd so if it's good enough for that, with the times it pulls, I reckon it's the way to go..