For the sigma automatic guys

[Scorpma82]

Not sure if you know this or not,

But i have been told that the valvebody in a BW sigma is infact interchangable with the valvebody with the BW35 Ford automatic...but the BW35 has a more aggressive shift pattern from factory.

I've also been told that (assuming ur car runs F/I and runs a computer) the BW41 4-speed automatic (out of the ea Falcon and maybe EB onwards) actually use the same casing as the sigma BW box but use different input shafts


So (in theory) this would be a very cheap mod to do and relatively easy to do (in comparison to a full blown conversion)

being and O/D gearbox, you could quite easily run a higher range of diff ratios (say a 3.9 or 4.11) without having the car rev it nuts off on the freeway


If other people have heard this...or done this....please let me know


Thanks guys

[A112H]

Most people under 80 and those who consider racing needs corners change to manual. As we are becoming a lazier society and more people think they can not drive a manual then I guess this would be useful.
Either way it is a very good bit of info.

[Torana68]

a manual is not the choice of box for Sydney traffic.....i fact they suck in heavy traffic. For crusing and commuting they are hard to beat.
Dont know what a 41 is but a 40 is 3 speed H/D... all the similar 35 ish ones are 3 speed. Id like to have a go at a CVT box

[Scorpma82]

Hi Torana

A BW41 is simply a 4-speed BW35...they are used in the EA Falcon and i think some later models before they went to the BTR setup

But the 4 gear (O/D) is electronic and needs the computers to control it

[Torana68]

google says for the EA:
Borg-Warner Model M51 three-speed automatic transmission was offered, however the latter was replaced by a four-speed BTR Model 85SXLE

[amgis_obrut]

yeah 35-40 and the m51 is pretty much the same box, i think the m51 has a lock up converter

ea 4 speed is an LE series box and is completely different to the older 3 speed boxes

[Scorpma82]

Yeah the base model Falcon was a 3-speed auto...however, the later models (of the EA) did run a 4-speed auto....all the Fairmonts and Fairlanes ran this 4-speed box.

I believe (dont quote me on this) the BTR was used from about the EF or so..

I've only got this info from an automtaic workshop who (used to) specialise in drag cars and hi performance apps


I personally wouldn't rely on google for information like that....but...each to their own

[amgis_obrut]

no the 4 speed in the EA-ED was the btr 85LE

who needs google as there was no bw41 fitted to any aussie ford, actually BW never made a model 41

[Torana68]

pretty much all I know about Fords is I wouldnt own one.... on this occasion I think Google is right, if there was a 4 speed BW35 similar box it would be a well known thing as the BW35's are in just about everything (worldwide, not just here) and everyone would be looking at a 4 speed option. Maybe its similar? size maybe?? they have a seperate computer? you may be able to adapt it but I seem to remember the early ford 4 speed was crap

[mic_77]

If you want a 4speed auto conversion just use the aisin box that is in the later 4g63 starwagons atleast it would bolt straight up and there are people that do valve bodies and shift kits for them.

cheers Mic

[Torana68]

dont spose anyone knows if they have a stand alone computer?