Who's running 3.7 diff gears?

GK · 04-09-2013, 11:12 PM

Hi All,

Anyone running 3.7 gears? If so, what are your experiences with such a setup?

I'm thinking of putting 3.7 gears in the auto wagon. The gears are currently in my SR manual, and in that setup, I always felt it was just that bit too low geared in first.

How does 3.7 go with the BTR auto? I was wondering if it'd be geared too low.

Also, what revs would the car be doing at 100kmph roughly?

GK

bloggs24 · 05-09-2013, 12:49 AM

Cant give you personal experience on them, but i bought 3.89's (havent put them in), and i was tossing up between them and 4.11's which everyone seemed to recommend aswell, dunno if 3.7's will be very noticable in the auto...

Sox · 05-09-2013, 07:28 AM

I've also used 3.7's in a manual, which I felt was great.

1st gear on the AU autos is very very tall, so I reckon 3.7's might just begin to feel ok.

4th's is also pretty tall, so I think 3.7's might just be a good compromise.

Bossxr8 · 05-09-2013, 05:45 PM

I've got a set of 3.7's that are waiting to go in. I thought 3.9's might start to be getting a little low so thought 3.7's would be a good compromise, as I do a bit of highway driving. 4 speed BTR.

Anything will be an improvement over 3.23's.

*ICEMAN* · 06-09-2013, 02:16 AM

It would fly with that ratio

MrEL · 06-09-2013, 08:48 PM

Will be good. I went to 3.9's in my 5.0 5 speed ute and its great.
Heaps of grunt off the mark and really tractable around town.
As an idea in 5th at 110km I am sitting at 2500 RPM.
First gear is a little short but since the motor is always on the torque curve my fuel economy improved.

mik · 08-09-2013, 01:59 AM

3.7s are not all that far away from the standard xr6 3.45 ratio, personally i think 3.7s would be alright( i would put that ratio in without hesitation), as the xr6 goes well but 1st gear in the btr still feels a tad tall on the take off even with the 3.45, on the highway i don't know the exact difference in rpm, i don't think it would to hard to bear going from 3.23 to 3.7.......
and i have often thought, while you might loose a very tiny bit of economy on the highway, i reckon you might actually pick it up in the burbs with the 3.7 diff(just a theory).

GK · 08-09-2013, 07:12 PM

Thanks for all the input guys!

GK

**BLU-220** · 08-09-2013, 10:02 PM

i was going put 3.45 lsd in my au ghia but now i'm going to with the 3.7 gears, with the mods i'm doing with it [220kw headers & hi flow cats, 1.7 R/R ] should work out alright, i just want the lazy AU 5ltr to have more get up n go. cheers dean

cuz · 10-09-2013, 10:04 AM

Just a quick question that is kinda off topic:
I have a '99 Fairmont v8 wagon with a LSD, can anyone tell me the ratio please?
Thanks

**BLU-220** · 10-09-2013, 10:18 AM

the info might be in here, but i think you'll have the 3.23 ratio
http://www.fordforums.com.au/showthr...=au+diff+topic

cuz · 10-09-2013, 04:39 PM

Thats my guess too mate.
I putting my old head under the wagon on the weekend, only to find that the sticker is totally faded and unreadable, it does have the LSD tag on the centre tho...