hey guys, how r yas all?? just wanted to know r the diff differ from the ea with 3 speed auto and the ea with four speed auto?? and if i install the 4 speed auto do i need to change the diff too or can the 3 speed do for the mean time till i get the lsd i want to get?? seeya's all blue_eyed

theres no reaon for you to have to change the diff just for a gearbox swap

the ratio was different AFAIK.

The 4 speed box will need the 4 speed tailshaft as the box is long or shorter, one of the two., for that matter you will need also a 4 bolt flange instead of the 2 U bolts style ones at the end of the 3 speed tailshafts.

So you'll need to change the diff flange, get a different tailshaft and that should allow your box change.

But if you want, stick in a 3.45 LSD in that. That would be better IMO.


Cheers

According to EA brochures the 3.9 CFI/MPI 3 spd auto had a 2.77 diff, the series II 4 spd 3.9 CFI had 3.08 and the MPI 3.23. All the 3.9 manuals had lazy 2.92 diffs! Interesting how in the series II they gave the lower powered engine the taller diff? Is that because it doesn't rev as well as the MPI? Or they they wanted the MPI to feel more responsive? Having never driven a CFI I have no idea what they're like compared to my MPI.

all i know is once the CFI get to about 3000 they sound like beasts. Have you noticed that, i definately have. But the responsiveness of them could be improved a bit as it takes a while for some actual power to reach the wheels in low revs.

Cheers

my MPI auto is a bit lazy bellow 2500ish, from there to 4500 it seems to be making some decent power and nice noises. I believe I have a fuel cut-out somewhere but anything above 4500 is a waste of time as it just makes more noise as opposed to progress. The lack of power at low revs is good and bad... good as in it's very user friendly when wet but I wouldn't mind some more low down response. Though it could be worse! I had an AU before the EA and that thing had a real touchy accelerator pedal, it was really responsive but on long trips it was a pain trying to keep your foot OFF the pedal trying to stay within the speed limit