Switch from auto to five gear = change the differential?

[CTDavies]

Hi all,
this was already briefly discussed at my restoration thread but I thought I'll place the topic here as well for more exposure. As some of you know I intend to replace the auto gearbox of my 69 2+2 with a fully synchronized four gear manual plus overdrive. The differential I have is a 3.3, according to the 43/16 tag. Can I use this differential as it is, or you would advise to go for another one with the new manual gear set up? Opinions and input please! :D

[JEP41]

Hi,

I have a 3.31 in my series one lightweight, driving through a Borg Warner T5 gearbox. I find this the perfect setup especially when doing track days, fast cross country driving and motorway driving in the E-Type :D

[Dave K]

I also have a 3.31:1 in my 3.8 with a 5 speed CJ box and it's perfect.

Dave

[Heuer]

I have a 2.88 with a 5 speed box but you need a high torque engine to make it work; 3,000rpm = 100mph in top. 3.07 is probably the best ratio to use with a 5 speed and a standard engine but down to you if you think it is worth the expense of swapping out that 3.31 diff. You can use this calculator to work out the expected revs in each gear: http://wahiduddin.net/calc/calc_speed_rpm.htm

[christopher storey]

If your tag says 43/16 then you have a strange final drive ratio . 2.88 was standard on European Auto 2+2 cars whereas 43/16 = 2.69 which is not a gearset I have ever heard of on a Jaguar . Do you think you may have misread it for 43/14 which is 3.07 . ( or 43/13 which is 3.31) .If it is 3.31 I frankly would not go to the trouble of swapping it for a 3.07

[CTDavies]

Oops! My mistake. The tag reads 43/13. I was quite surprised about the 2.88 as my car is from the US. So it's most definitely as 3.31. As I can see that some people here have fun with a 5-gear/3.31 set up, I think I might stick with what I have.
Chris

[Dave K]

Chris,

My gearbox is virtually the same as my Moss from 1 through to 4th gear with a 5th the revs really drop off and so does the noise.

Dave

[Heuer]

Jaguar EJ 4 speed, P4000 tyres, gear changes at 5,000 rpm:
3.54: 41, 63, 87 and 110 mph
3.31: 44, 68, 93 and 119mph
3.07: 48, 73, 100 and 128 mph
2.88: 50, 78, 107 and 136 mph