Hi all, how would I identify the diff ratio in my 1982 Series 3 XJ6? Are there any markings on the diff case perhaps?
Cheers Nick

 

Most likely 3.058 or 17/52, if not 3.07 or 14/43. Not sure if series 3 fitted with the little aluminium plate noting the ratio.

 

Originally there was a small tag on bottom cover bolt that told you the ratio. If it's not there, jack the rear up (safely supported), put a piece tape on tire and pinion yoke. Turn pinion, counting revolutions, until the tire has gone exactly one revolution. This will give you a close approximation and then research the possible ratio's that were available and pick the closest one. E.I. pinion turns a little more than 2 3/4 revolutions to one tire revolution, 2.75:1, only I don't think Jaguar made that ratio, but they did make a 2.88:1 and it was very common in the S3's. I'm guessing that's what you have. That's what my 1985 S3 has.

Dave

 

Thanks for that I will give it a go at the weekend
Cheers Nick