Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: youngkadettkinin on 16 February 2010, 21:13:48

Title: strongest GM RWD gearbox(manual)
Post by: youngkadettkinin on 16 February 2010, 21:13:48

i'm new here, just want to know what is the strongest manual gearbox GM make (i.e torque rating). The strongest i know of is the R28, which is rated for 280nm's(hence the 28 in r28). What  gearbox does the diesel omegas use?
Cheers

Title: Re: strongest GM RWD gearbox(manual)
Post by: pedroMV6 on 16 February 2010, 21:17:08

Apart from looking Stateside at Corvettes, Camaros and trucks, a Getrag 265 as fitted to some Monzas?

Like rocking horse shit to find though! ::)

Title: Re: strongest GM RWD gearbox(manual)
Post by: tigers_gonads on 16 February 2010, 21:26:22

diesel omega's use the r25 box for the manual
ar25 for the automatic  :y

Title: Re: strongest GM RWD gearbox(manual)
Post by: Entwood on 16 February 2010, 21:28:58

Quote

diesel omega's use the r25 box for the manual
ar25 for the automatic  :y

Recomended to fit the AR35 if you chip the diesel.  AR35 fitted to the 3.2 V6 petrol auto as standard .. :)

No idea what manual box that has .. but it might be stronger ??

Title: Re: strongest GM RWD gearbox(manual)
Post by: Welung666 on 16 February 2010, 21:31:23

Ex-cops use the R28 aswell even in 3.2 form.

Title: Re: strongest GM RWD gearbox(manual)
Post by: youngkadettkinin on 16 February 2010, 21:40:48

Thanks for all the help, anyone know does the monaro use the same gearbox bolt patern as GM's big block petrol engines(eg z22se, x20xev ect)? I know its a long shot :y

Title: Re: strongest GM RWD gearbox(manual)
Post by: 2woody on 18 February 2010, 13:13:09

a couple of things here.......

All Omega A and Omega B manual gearboxes are Getrag 240, made in a GM-specific casing and with either shot-peened gears or not, according to the usage.

A Getrag 240 without shot-peened gears is called "R25"
A Getrag 240 with shot-peened gears is called "R28"

The bell-housing for these is integral with the gearbox casing and comes in three shapes - 4-cylinder petrol & diesel / V6, 6-cylinder diesel and "cam-in-head"

Other than that, there was a Getrag 265 used in some Senator A and Monzas, which uses a separate bellhousing. Beware, though, this bellhousing is "cam-in-head" bolt pattern and won't fit any Omega B engine.

There are three other strong GM boxes :-

ZF 6-speed. Used in Lotus Carlton - fits "cam-in-head" engines

Tremec T56 used in Commodore and Monaro - fits V8 only

Borg-Warner T5. Never used in any V-car

If you're contemplating more power, you don't automatically need a stronger gearbox. There is a natural limit for how much torque you can put through a 'box - and that's when the wheels spin. The "worst-case" for any gearbox is going to be re-starting a car with a heavy trailer on a hill.

hope this helps.

Title: Re: strongest GM RWD gearbox(manual)
Post by: 2woody on 19 February 2010, 08:53:09

thought of another option. You could fit a Ford "Type 9" box, using a specialist "conversion" bellhousing.

it's another option, but probably not much stronger than a "240".

Title: Re: strongest GM RWD gearbox(manual)
Post by: unlucky mark mv6 on 19 February 2010, 09:38:25

Quote

thought of another option. You could fit a Ford "Type 9" box, using a specialist "conversion" bellhousing.

it's another option, but probably not much stronger than a "240".

If its a ford part,its probably about as much use as paper mache. :D

Title: Re: strongest GM RWD gearbox(manual)
Post by: 2woody on 19 February 2010, 11:35:07

Aye, they're a bit "chocolate", but able to be rebuilt into something a lot stronger. The Caterham 6-speed version is actually quite a decent box.

all completely different to the Getrag units, for which there's nothing available.

Title: Re: strongest GM RWD gearbox(manual)
Post by: biggriffin on 19 February 2010, 20:11:15

arnt some of the boxes on beemers compatiable with gm fittings