Dear Friends,

I want to know if it is possible to change only the gear ratio in a xj12 diff.

My current ratio is 3.31 and want to change the ratio to 3.54 ( keeping the diff lock )

my idea is changing only the ring gear and pignon, or maybe other ideas ???

 

3.31 to 3.54 is just a small jump I dont think it would be noticeable, especially on a v12.


Not easy to do. Not low cost to do right...the ring can modified but the pinion is different.

You need a the dana 44 to Jag flange and a diffrent seal

DANA SPICER 2-1-1881X companion flange fits all Dana 44 front or rear with 26 spline pinion

Here are some detailed diffrences
Jaguar salisbury/dana 44 gear swap conversion kits???? | The H.A.M.B.

 

johan,


I switched from a 3:31 to a 3:54. I shorten the route by buying a center section from Coventry West. Spoke with Dick Maury. "Shortened the route" is a misnomer, as I freshened everything else.


Ahead of the 3:54 is a 700R4. Makes a nice combination in my case. The 12 & T400 were good or 11 MPG. The new combination with a BBC gets 14 MPG if I keep my foot out of it.


At times, I wish I had went to the to a 3:90 - quicker in the city and the 1/8 mile.

 

i have a 3.73 ratio in my XJS, also went to 700R4, makes great acceleration and cruising, in OD ratio is 2.60-1. best of both worlds.