hi

putting a lsd diff into the ed fairmont with normal diff, put a new speedo sender in and wondered if the new sender would work with the new lsd diff or if itd need a new sender.

how does a lsd digg get rebuilt

Speedo sender is in gearbox - not related to diff, diffs are tricky to do yourself, best get it done by a pro, although can be a bit pricey!

so will a 3.45 diff put the speedo out

You need to read this:

documents.php?d=30

If you actually understand how it works then use the calculator to work out what speedo gear you need to suit your car and it's wheel size.

If it makes no sense to you at all you probably shouldn't be doing the Diff swap.

What are you changing to 3.45 from??

If you're going from 3.08 or 3.23 then you're virtually wasting your time as the ratio increase will be barely noticeable - need to go to at least 3.7 for a decent improvement in off the line performance AND an improvement in traffic speed vs gearbox matchup.

If you're just after the LSD function (hope you know how to handle it?? - otherwise will look forward to seeing your car in the wrecker pages - and hope you survive the crash of course) then carry on...

I changed my NF 5.0 to 3.45 from 3.23 and the difference is noticable - not earth shattering but a good difference! 3.7's usually cost a bomb though 3.89's might be a cheaper option.