I have a de-dion CEC with a 3.92 open diff and push-in half-shafts

I also have a 3.62 LSD with bolt on half-shafts sitting in a box.

The bolt-on half shafts will not fit the hubs, and are too long for the width of the car.

The LSD is the right size to fit the car.

Is it possible to convert the LSD to accept push-in half-shafts?

Are they all Sierra parts?

If so then I believe you can remove the bolt on stubs from the diff and refit the push-in shafts. I may be wrong though!

Alternatively you may be able to transfer the internals, but that's getting a bit more involved!

[Edited on 25/10/10 by nick205]

are you using drum rear brakes?
i have just this week carried out this very same mod
i am running a 3.62 lsd diff that takes bolt on type drive shafts,what you need is a set of push in type sierra dohc driveshafts then remove inner cv joints and then fit the bolt on type joint thus making a hybrid drive shaft having a tripod push in type on the outer so you can still have drums and a bolt on type inner so you can have a lsd....problem solved hope this helps message me if ya need anymore info but think this should cover it.

I've been researching this a bit lately and from what I've seen in other posts you need to be carefull which parts will fit together.

You can swap the crown wheel and pinion between the LSD and non'LSD diffs if they are both 7 inch or both 7.5. This would let you select the best ratio to put into your LSD diff.

Cosworth LSD with 108mm driveshaft hubs will probably not work because the splines on the inside of the 108mm CV do not match the splines on a tripode type shaft. I think you need to make sure you use 100mm driveshaft type LSD, used on xr4x4 etc. Then the 100 mm lobro joint should fit onto the inner end of a tripode driveshaft and keeps the correct overall length. Even then I think it only works if the tripode driveshafts are from a 1.6 estate, 1.8, 2.0, 2.3, 2.8 as the others have a different spline on the driveshaft. Maybe there is a matching 100mm lobro CV to go on the smaller driveshafts, but I haven't been checking for those.

Both the 27mm and 28.5mm driveshafts supposedly have the same splines at the ends.

Also seen a note to avoid the 28.5mm diameter driveshafts from the v6 as they are liable to break at the machined part where the rubber boot fits. Maybe thats only with the torque of the v6 but the shaft is only going to be as strong as the weakest/thinest point.

All this is just internet research so check yourself before you commit to any costs. I haven't tried it myself yet.

Guessing your de-dion CEC has custom length driveshafts. So you would need to re-use the driveshafts you have and then match a lobro CV to the splines on them. I have a similar issue on my car, the shafts were shortened by the kit car manufacturer, so I plan to re-use them rather than modify some more, to save getting professional welding. Might add a sleeve over the weld if I remove the tripode again.

I have rebuild the tripode joints on them once already so not too worried about taking one off to try and fit a lobro CV to it. Might cost me a new tripode cover if I mess it up and need to go back to push in driveshaft diff.

Not sure if you would want to open up one of your inner tripode joints to try the modification without knowing how many splines on your driveshaft. If it's a custom shaft I'm not sure you could rely on the diameter to tell if it's 25 splines on the end.

I think it's only one side of the LSD diff that does not accept a push in driveshaft. Not sure if left or right, but one of the output shafts of the LSD is shorter. Maybe you could modify only one driveshaft to lobro. Leave the other side as a push in tripode and remove the output shaft of the LSD on that side.

This depends on the size of the push in driveshaft splines matching the splines on the LSD output shaft.

Dave4kids has just had lobro flanges added to a push fit diff, the rear left stub jams on the planet wheel axle.
It looks like a couple of mm taken off the end of the spline will cure the problem, but it's not on a LSD

You cant convert an LSD to take push in shafts.

If its a standard open diff with bolt ons its as simple as removing the flanges then push in shafts will fit straight in.

However the push in stubs are different lengths on the LSD so push in shafts wont fit.

You can make hybrid shafts, however they tend to eat the lobro joints as there is a lot of spring pressure created by the tripode joint.

David

^^^ what David said

the only LSD's that can take push-in shafts are the aftermarket ones

if I were you I'd keep a look out for a cheap set of bolt-on hubs and shafts