Spitfire 1500 4 stud 3.63 differential

[Paul H]

Hi , will this fit a Vitesse mk2 which has a 6 stud fixing ? 

Paul 

[johny]

Im considering the same change which I believe has been done successfully by many owners and it will certainly fit with no problems even using the original clamp plate by just leaving out two of the studs. However I think Triumph must have used 6 in this strange layout to better resist the force developed between the studs and casing when one back wheel hits a large bump. As theres no 'swing spring' to dissipate the energy the risk is probably that the diff casing will fail around the stud hole and I have seen photos of this but without knowing what caused it. If this did happen and caused some sort of accident it would certainly be difficult to explain to your insurance company😮

Also I see that Canleys offer an aluminium casing for these diffs which comes with 4 holes but they recommend drilling two extra holes for use on non swing spring vehicles.....

[Colin Lindsay]

Cases are easy to find, Paul; it's the internals that everyone wants. You should be able to pick up a 6-stud case easily enough, although carriage may be costly; in fact most of the diffs on eBay, and there are at least two six-stud versions, are collection only. 

There's also a four-stud case only, £25, which may be handy if you want to try drilling and tapping one but need a spare just in case.

[Paul H]

https://www.ebay.co.uk/itm/Triumph-Spitfire-GT6-Vitesse-3-63-differential-with-Polybushes/133505891241?

seems worth a punt 

Paul 

[Clive]

2 hours ago, Paul H said:

https://www.ebay.co.uk/itm/Triumph-Spitfire-GT6-Vitesse-3-63-differential-with-Polybushes/133505891241?

seems worth a punt 

Paul 

Careful with that. AFAIK all 3.63 diffs used a collapsible spaced internally, and that meant a nyloc, with a cap over it. That diff has a castellated nut, so buyer beware!

Re cases, it is a doddle to swap a rear case. Hardest part (or not) is undoing the cap-head bolts that hold the 1/4 shafts in place. Just needs a new gasket for the case, and a smear of sealant when you pop the 1/4 shafts back in.