mjcwrx

Hi all,

Been a while since I have been on here, but this one has drawn me a complete blank, no thread or manual or chart can tell me the right ratio for my box, none of the charts seem to have the newer boxes listed, and there seem to be conflicting answers on threads as to which ratio is right. The box number is TY754VG7AA but the 2006 manual I bought suggests a 3.7 ratio diff, I have tried that but I get terrible vibration if on a motorway, as the centre diff seems to be winding itself up.

Any Ideas , Help!!! Or has anyone got a rear diff to match this box for sale, they seem to be like rocking horse im guessing coz the new age boxes are stronger.

Cheers

Matt

mjcwrx

Oh by the way , Im running it in a 2001 car, so if anyone has any questions about converting the front end I may be able to help. Basically you need the later driveshafts clutch cylinder and flywheel! I put a whole new clutch kit on as and have my old AP racing organic one for sale if anyone is interested:

its on ebay item number 330382501609 £150 !!

mjcwrx

Anyone?? Yet another manuall in the post this morning from eBay and still my box ref isnt listed, I have just bought a 4.111 so will let everyone know once and for all if its correct.

2ndgear

a mate on mine had one of these and it was 3.9 at the front with a 3.54 at the rear

mjcwrx

Hi,

The 3.545 I had in before wouldnt let me hit 70 in a straight line before an insane amount of judder bought me to a holt, So its deffo not that! I have been running a 3.7 with some sucess since feb untill my 1st motorway run same again insane judder at 70mph but only afer a few junctions of traveling at the same speed in a straight line. As the 3.7 has helped im gussing I need to go higher still so willing to give the 4.111 a go. Would be nice for some definate confirmation.

Cheers

Matt

Fat Boy

never heard of a 3.7...

P20SPD

iTrader: (1)

3.7 was in some of the foresters iirc.

The code suggests its from an 06 hawkeye. When you have pulled it appart did you count the teeth on the crown wheel and pinion for the front diff? Did you also count the teeth on the drop gears in the transfer case. Doing this will tell you exactly what rear diff you need!

Are you sure the centre diff hadnt been fecked when you bought it., as i suspect it will need a 3.9 front diff, 1.1:1 transfer gears and a 3.5454 rear diff.

mjcwrx

I bought a manual on fleabay which said it would be a 3.7 rear!! No wonder I could only find a leagacy one , it did improve the problem so im going in the right direction. Hopefully the 4.111 will do the trick. I could always pop my old centre and a front diff ( have several of them from previous box explosions )and use my old rear was hoping to save all that work.

Arch

iTrader: (59)

Steven think Daz Davies has been playing about with his and he seems to think its a 4.11 rear Diff. I have one of thee in the shed gathering dust because of the clutch and final drive issues

172sport

iTrader: (6)

I'm picking it up off him next week.

Probs split it before fitting it just to make sure of the ratio's.

I'll keep you posted.

mjcwrx

Hi,

Daz PM'd me about the ratios and he confirmed I need a 4.1 Ratio, Its now turned up so im going to pop it in as soon as I get the chance. I cant believe its so hard to find a proper UK spec Manual or a Ratio chart for all this stuff its a minefield! I will definately update this post when I know for sure if its right. So if the gearbox code is googled again somone will have a definate answer for the TY754VG7AA box.

Cheers For All your Help Guys A*

mjcwrx

Hi, Guys took a while to get the box out due to new baby but the ratio issues have caused the centre diff too fail quite spectacularly! I have a centre one from an earlier box can I just pop that in. The front diff is a 3.7 ratio counted the teeth on the diff 37 and pinion is 10 and my rear is a 4.111 now just need to check the transfer gears now. I assume the damage had already been caused by running the 3.545 and 3.7 rears. Any thoughts?

Fat Boy

Id say so - any large ongoing disparity will cause centre diff meltdown

mjcwrx

SANY0229.jpg picture by Matt_C26 - Photobucket

I have now stripped the box and can confirm front diff for my TY754VG7AA is 3.7 ( 37 diff on a 10 pinion ) with the transfer gears both at 31T so 1:1 ratio from this and the information you guys have given me make me 100% sure I need a 3.7 rear LSD any one got one for sale??

172sport

iTrader: (6)

Bugger!!!!!!!

172sport

iTrader: (6)

Mmmmmm

https://www.scoobynet.com/drivetrain...rear-diff.html

dazdavies

iTrader: (22)

Simple, go confirm with your local dealership.

Ask them to show you their parts system. The exploded view of the 2.5 WRX transmission system clearly has 4.11 ratio written next the rear diff. I've seen it with my own eyes. If you wish, I'll take you to my local dealership so you can see it with your own eyes.

Infact, if it doesn't I'll buy the bugger back.

172sport

iTrader: (6)

I dont doubt you, but surely MJCWRX can count and he has one in bits in front of him.

dazdavies

iTrader: (22)

I'd rather take subaru's word for it. Like I said come to St Leger Subaru I'll show you myself.

Have you tried the box with a 4.11 diff?

172sport

iTrader: (6)

Nope, not yet fella, its still surrounded by boxes from the house move. LOL

PeeVee

iTrader: (1)

I would have to agree with Daz on this..... All european 2.5L wrx 5spd boxes have a 4.111 front & rear diff fitted... Period... There simply are no other options available.

The way I see it is there are 2 choices here..

Either there has been a miss count on the pinion and it has 9 teeth instead of 10, which would make it a 4.111..

OR

The box you have, did not come out of a wrx, it came out of 2.5L normally asperated Legacy built after 2003 as these do have a 3.700 front diff fitted, they also run a 1:1 drop gear so you would need to source a 3.700 rear diff from a post 2003 2.5L SOHC Legacy & hope that you can fit the crownwheel & pinion to you diff assay as the legacy diff unit is not suitable for a wrx & won't accept your driveshafts.

Good Luck
Phil

dazdavies

iTrader: (22)

The box in question is without doubt from a 2.5 WRX I saw it being taken out of the car myself.

I think the teeth have been counted wrong there is no other explanation.

mjcwrx

Im almost 100% sure I counted right, did it 10 times just to make sure, but will open the box back up to check and photograph so you guys can see. I saw one on ebay with the same TY754VG7AA code from a wagon maybe they use a 3.7 ratio? Daz are you sure you have seen this box before I have had it a while?

mjcwrx

I am running a legacy rear diff its the only one I could find in a 3.7 sounds like I may well have a legacy box, I have just converted it to a LSD with the parts from my old 3.545 went togeter like a dream so looks like they use the same diff casings and driveshafts. I damm well hope its a 3.7 front after spendin all last night building the rear diff!

dazdavies

iTrader: (22)

Not your box no but 172 sport is having the same issue as you. I sold that box to him. I am 110% that one is 4.11.

Fat Boy

The SPDA - Transmission Chart

Have a look here - no 3.7 diffs anywhere, but then your box code seems not to be an impreza code either.

As Steven says above he thinks that a 3.7 might have been fitted to a forester but only might - and that's from a person with an awful lot of experience with Subarus and their gearboxes in particular. I note the other poster who says that he knows of them in Legacys as well, but they were definitely not fitted to wagons or other imprezas as oem - perhaps that box code is one for a forester or legacy?

PeeVee

iTrader: (1)

Not a forester code as the forester has only ever had a 4.444 or 4.111 fitted

PeeVee

iTrader: (1)

Have just done some more home work on this & the transmission code TY754VG7AA is definately from an impreza 06my wrx 2.5 Ltr and has 4.111 front & rear diffs fitted.

Have a look here: SUBARU IMPREZA WRX HAWKEYE 5 SPEED GEARBOX 44000 MILES on eBay (end time 05-Apr-10 16:04:51 BST)

The seller of the box has posted a photo of the Vin plate attached to the car, you can quite clearly see a trans code of TY754VG7AA and a Vin no: that belongs to an 06 wrx saloon. The engine code of EJ255 confirms that it has a 2.5 Ltr turbo charged Quad cam engine.

When you input the vehicles Vin no: into the subaru parts system it gives you a front crown wheel and pinion ratio of 4.111.

mjcwrx

Hi,

Just to clear things up, that SPDA chart is so outdated hasnt got any of the late boxes on, this gearbox code is definately used in late 2006 Hawkeye wrx's see the link above vin plates dont lie! I cant belive subaru would use 2 ratios in the same box unless mine is some king of diy hybrid!

Will wait for the final count later in the week!

mjcwrx

Hi,

Phil (PeeVee)

Looks like we both saw the same listing on ebay! Can you confirm the ratios front transfer and rear on the system, at last someone with the tools: is it

Front 37/9 (4.111) Centre 31/31 ( 1:1 ) Rear LSD 37/9 (4.111)

Cheers

Matt