Broken 4EAT - Gearbox Replacement Options
 

Just before Christmas my 2004 Subaru Legacy suffered a catastrophic engine and gearbox failure when the driveplate connecting the torque converter to the engine decided to shred itself at 4000rpm taking out the engine block and gearbox :cry:

Detailed thread HERE - though Im warning you the photo's aren't exactly pretty :D

We have sorted all the bits necessary to rebuild the engine, but Im having difficulty sourcing a compatible gearbox.

My current gearbox code is: TV1B7MFAAB - 2W

If necessary Im happy to transplant a gearbox and matching rear diff, but I need to know which gearboxes will be compatible with the connectors on my car, and work properly with the main ECU.

For reference its a 2004 Legacy 2.5 SEn Automatic with an EJ253 engine.

Thanks in advance for any information.

LegacyBod

Hi there

What I know yes you can swap another 4EAT from Impreza/Legacy or Forester to yours,just you will need to have TCU from the 4EAT what you want to buy,without this will not work as should.

Legacy 4EAT are not stronbest,i would suggest have look for 4EAT from Impreza with Tiptronic/Sport shift,this box will handle more power on longer run and will be more reliable,but still you can save money and get yours 4EAT rebuild to stronger one by IPT or other companies from USA,price for rebuild really varies and really I would contact them

Friend running his built 4EAT with 500hp at USA few months without the issue,although some people have issues with them

4EAT replacement parts you can get from USA without the problem,they're not expensive,I think they're cost around 400USD which is not so bad

Hope this help


Jura

Even after the rebuild my car will only be pushing 170bhp max, so even a Legacy gearbox should suffice :)

Regarding the TCU - is there a direct connection of any sort between the TCU and main ECU??

My biggest worry is buying a gearbox, matching Diff, and TCU - only to find that the TCU wont talk to the rest of the car!

Aha,in that case you should be OK with standard Legacy 4EAT although they're not most reliable 4EAT

Yes there is direct connection between the 4EAT and ECU,yours 4EAT have paddle shift option(Sport shift as is called on Subaru 4EAT)?

If you can download wiring diagram on the Legacy and under TCU and ECU,both are connected,which means

But still would go with 4EAT from yours Legacy(which is for year 03-08),will be less hassle with that and mainly you will don't need swap the TCU

I know friend swap the his 4EAT to Legacy 4EAT(similar to yours year) and he ended with headache with wiring and other bits,at the end he sold the Legacy 4EAT and bought Impreza gearbox

Not sure what is involved swap Impreza 4EAT to yours,but would have look on the Legacy forum and on the Nasioc,there have lot more experience with them than here in UK(in UK 4EAT is not most common gearbox)

Jura

Thats basically the problem. OpposedForces.com lists a number of different gearbox codes for my car - but I cant find any of those for sale.

I have found a TV1B7MFBBB gearbox, but dont know if it will be a straight forward drop-in for my TV1B7MFAAB box??

Similarly I have also found a forester box that appears to be a later version of one used in the Legacy Outback - but again Im unsure whether that will work with my TCU..........

Thanks for the info though :)

Technically will fit this box in yours,yours is VDC or non VDC model? Or you have VTD diff?

Because usually those Ouback from which is TV1B7MFBBB have VDC,if is yours non VDC not sure workaround ,VTD is usually on 4EAT Impreza or Legacy,Forester and other cars

Just ask seller from what model is this gearbox,if have VTD or VDC and from this I would go

TCU is no problem replace if needs to be replaced




Jura

I think thats the same box as in the SVX? if so I have an SVX here which is no good for anything other than breaking..

Let me know if of use, wont want much for it.

Simon

Just have look which you have 4EAT,you can simply have look on this gear surround/shifter

http://images.dealerrevs.com/gallery...hp?id=45788902

Those bellow have usually paddle shift

http://i44.tinypic.com/2nvyufn.jpg


Jura

doesnt look like either so perhaps its not a 4eat

definitly a 4eat box in the svx but assume the shifter is different

Yes SVX has have 4EAT,probably older which you can find in older Impreza(although is not the same,but is similar,SVX i think have more function plus there is cracked code for SVX TCU,what I know only SVX has have cracked TCU code)

Here is yours

http://www.spannerhead.com/wp-conten...Interior_2.jpg

Impreza

http://farm9.staticflickr.com/8435/7...6f247de0_b.jpg


Jura

Thats the same surround as on mine (though reversed right to left) - but mine has no paddle shifters.

My car does have VDC (which I believe was an optional extra) as I also have the VDC off button just below the steering wheel.

Im still waiting to hear back from a few places regarding compatibility but all information welcome at this point!

PS - Anyone know is all TCU units from 2003-2004 cars have the same pinouts to the main ECU? If they do then it might be possible to try and find a 5EAT with matching diff and ECU and drop that in instead :D

Hi there

Some cars has been equipped with paddle shift some not,yes VDC has been usually for extra or I've seen them in Outback or usually on JDM Legacy/Impreza with 4EAT,but many people still mistaken VDC with VTD

Not sue on pinouts,but from this link,doesn't looking like possible,if yes will cost you lot more than 4EAT

http://www.subaruoutback.org/forums/...4eat-5eat.html

Probably best is have look for JDM 4EAT with sport shift,not sure but someone here selling the this 4EAT with sport shift:thumb:


Jura

Thanks all for the advice, but after struggling to find any compatible gearboxes (due to my Legacy having VDC as an optional extra) - and even IMGroup techies drawing a blank for compatibility with other gearbox codes, then I had to call it a day and am in the process of scrapping the car for parts :(

Its not all bad though - Im now driving a Fozzy XT and slowly patching it into something resembling a half decent state :D

Hi there

Sorry hear that,but hopefully yours new Forester XT should be good one,with some bits like gearbox etc is really only option try to source from USA or Japan

Do you tried some companies about the rebuild yours existing box


Jura

Hi there

Sorry hear that,but hopefully yours new Forester XT should be good one,with some bits like gearbox etc is really only option try to source from USA or Japan

Do you tried some companies about the rebuild yours existing box


Jura

Didn't bother as the forces involved broke the main thrust bearings, cracked the engine block, cracked the front different and gearbox casing and toasted the torque converter :(

So a complete new replacement unit was really the cheapest way to guarantee a working box, as the gearbox internals may well have taken a battering as well as the casing!