ST-R auto gearbox issue

[Subaru ETA]

yup sounds like the troque convertor splines..

what i would do is pull the box out first and look at the torque convertor -you will be able to see if it has ripped them apart...

i know that gorge very well (my family are from waihi) were you accelerating out of one of the many tight corners when it shat itself?

[confusis]

im in katikati and the nearest pickapart is in tauranga and doesnt have any v6 legnums/galants

[bradc]

Some parts are the same with other w4a42 gearboxes installed in other mitsi's, but the torque converter is a unique part to the 25ST-R and 25ST

[confusis]

don't have the tools to pull thge box off unfortunately.. wasn't even accelerating - was stuck behind other cars

[Subaru ETA]

you going to get it into a shop to get the work done?

[confusis]

as i said before - lost my job so im broke

[scott.mohekey]

Where are you based?

[bradc]

katikati which is kind of near Tauranga

[confusis]

yup. first i have to get the car finally towed back to my carport - its still stting at a friends place

[crazydriver81]

I've just checked ASA...

The torque converter is p/n MD761878 or MR983439 and these parts are compatible to any EA5W / EC5W cars with the V6 N/A engine. It is not important, if the auto-box was a tiptronic one or not (at least ASA says so...)

Maybe this information helps to find a used part...

[confusis]

thanks

would it be possible to use the vr4 trans with the vr4 trans comnputer? or are they totally different? mmm 5 speed auto st-r. just asking as there are nil str boxes available on trademe/local wreckers and there are a few vr4 trans avail

[bradc]

I don't know if it will work. I do have both at my place though if you're willing to pay for them!

[confusis]

are the bellhousings transferable between boxes? still need a torque converter though. none on trademe

[crazydriver81]

Would be good to know if the VR4 auto-box will fit the ST-R. That would be one of the next mods to think of (especially in case of fuel economy and the 5 gears).

For sure you have to change the auto-box ecu and the instrument cluster, but I don't think that the bell housings will differ so much because the engine block is the same (6A13).
I have to check the p/n of the bell housings when I am home from work, before I can give you an answer on the transferability of the housings.

[bradc]

The casings are different, but the metal plate that resembles a gasket that sits between the gearbox and engine are the same for all 6a12 and 6a13 engined legnums. The gear ratios are as follows:

1st 2.842
2nd 1.529
3rd 1
4th 0.712
Final 4.042

1st3.789
2nd 2.057
3rd 1.421
4th 1
5th 0.731
Final 3.684

This translates into max speed in gear (at 6000rpm) of:

62.2
115.6
176.7
248.2


51.2
94.3
136.4
193.3
265.2

[crazydriver81]

Thanks Brad for the technical info.

This means that (assumed I put a VR4 box into my 25ST-R) the acceleration would not be as good as now, correct? But when driving on the motorway with a certain speed, the rpm's will be lower with the 5spd box. So the loss on acceleration will be leading into a mor economic fuel consumption. Hmmm...really a mod to think of.

Regarding the box housings, indeed they must be different, but the housing of the torque converter, which is connected to the engine block, shall be the same. Did I got you right? Have to check that with ASA...

[bradc]

Acceleration would be better in 1st to 4th by quite a bit, a good 15% or so. However the additional gear also lets you cruise at lower rpm's.

Check ASA when you get home to confirm all the other similarities

[crazydriver81]

errr... sh*t

I've checked that with ASA. Neither the bell housing nor the mounting brackets have the same number. The small pictures seem to be identically.

I am afraid only an eye-to-eye comparison can help here. Anyone who has a 4spd and a 5spd auto-box stored in his garage?

[bradc]

I have a VR-4 auto gearbox, but my ST-R is a manual

[Ryan]

I am afraid only an eye-to-eye comparison can help here. Anyone who has a 4spd and a 5spd auto-box stored in his garage?

Perhaps Confusis and Brad could both take a detailed picture of the part in question and then compare the two?