Is a Quaife LSD simply an add on to the existing bevel gear and ring gear or do these parts also come new?
It's just the diff, it doesn't include the bevel and ring gear. I can't answer any of the BTR questions as mine is a Salisbury axle, but I'm sure Billy Bellinger would know. My axle was rebuilt 10 years ago and at that time it was no problem to get a Morgan ATB from Quaife, but I have no idea what availability is like these days. I'm sure they could make you one though.
If you look at my link a few posts above Tim/Heinz you will see that Quaife have them in stock for BTR axle.
Thank you, Richard. Quite apart from my desire for a shorter final ration, re the ATB differential from Quaife, can anyone be sure that it will fit the latest version of the BTR rear axle? According to SimonH the 2014 axle with 7.7" ring gear. I wouldn't be so sure because the ATB seems to be made specifically for the M76 axle, and that should be the 7" diameter ring gear axle according to SimonH. See my post, the first of page 3 of this thread. Simon: The diff carrier (the pigs head) in the middle of the axle is also physically larger and heavier“.
I do not know if this has an influence regarding the fit of an ATB.
Tim, thanks for the recommendation, I wrote a mail to jb-engineering (Billy Bellinger) concerning all this stuff and will see next week what they will response.