6MT Master Swap Thread

This is the difference and why the seals leak when using the LGT axles. Notice how much thicker the LGT axle is where it goes into the trans. Sundials and seals need to accommodate that extra thickness.

 

http://legacygt.com/forums/attachment.php?attachmentid=169558&stc=1&thumb=1&d=1386352294

 

 

 

In this link soarer has come-up with a "hybrid" solution using 2002 WRX inner CV joints, which is what your friend's Bugeye uses.

I just discovered (knew but didn't make the connection?) that my 2008 Spec B 6MT was also the first year for VDC in the Spec B.

 

I don't think that there's any VDC "electronics" associated with this 6MT box, nor is there any difference in the center diff torque split, which still should be viscous and 50/50 correct?

 

Anyone have specific experience with the 2008 Spec B box during their conversion, that can confirm? TIA.

I just discovered (knew but didn't make the connection?) that my 2008 Spec B 6MT was also the first year for VDC in the Spec B.

 

I don't think that there's any VDC "electronics" associated with this 6MT box, nor is there any difference in the center diff torque split, which still should be viscous?

 

 

As I know it, all the data the VDC uses comes via CANbus, and no sensor on the trans (5MT or 6MT) communicates via CANbus.

I just discovered (knew but didn't make the connection?) that my 2008 Spec B 6MT was also the first year for VDC in the Spec B.

 

I don't think that there's any VDC "electronics" associated with this 6MT box, nor is there any difference in the center diff torque split, which still should be viscous and 50/50 correct?

 

Anyone have specific experience with the 2008 Spec B box during their conversion, that can confirm? TIA.

 

all 6MT spec.Bs ('07-'09) have VDC. and yes, 50/50 split through a viscous LSD. front diff is open and rear diff is Torsen LSD

Power still goes through a gear reduction 1.1:1

Power still goes through a gear reduction 1.1:1

 

That 1.1 ratio comes from the "transfer drive gear" and "transfer driven gear" which are in between the center diff and the prop shaft. The ratios at the center diff are equal because 1.1*3.54=3.90. The center diff "sees" the same gearing... it is the same as if the front and rear diffs were 3.90 with a 1.0 transfer. As to why Subaru did this... I don't know. I've never seen a good explanation on here or on NASIOC.

Chris - the 1.1:1 is to enable the front diff, which is running at 3.545 to match the rear diff, which is running at 3.90. 3.545*1.1 = 3.90. At the axles, the diffs need to turn at the same speed, that's why there's a gear reduction between them to match them up. 3.545 would be turning faster than 3.9 so the gear reduction internal to the transmission slows down the rear drive shaft. The center diff isn't the gear reduction so it should still function as a straight 50/50 VLSD CD. At least that's the way I've always understood it.

Sorry CWW - had this all typed up and stopped for dinner. So, what you said.

yea i dont get why subaru did that 1.1 reduction for the front diff..

I picked up an '05 LGT that has an '08 STi tranny swapped in. I didn't perform the swap so there's a lot of stuff I don't know. If I want to swap out the SPT STS that came with it, should I be looking at STS's that are compatible with the '08 STi? Spec B?

 

As a side note, I suspect the shift linkage in the car is also from an '08 STi and I plan on swapping it out for Spec B linkage.

Just wondering why you would change the linkage out for the spec b one? I believe there are only minimal differences between the two.

Just was curious because I just did a 5eat auto to 6 speed swap on my 05 lgt. I used the auto axles and use the 08 sit linkage

There is next to no difference between the STi and Spec.B STS. I have a '10 STi transmission and a Spec.B STS from Cobb. The difference between the two shifters is in how the shift boot attaches... nothing more.

Just wondering why you would change the linkage out for the spec b one? I believe there are only minimal differences between the two.

Just was curious because I just did a 5eat auto to 6 speed swap on my 05 lgt. I used the auto axles and use the 08 sit linkage

 

I looked at this post and saw that Impreza linkages are a bit shorter and can cause neutral to be slightly off center. I do city driving in NYC and have looked for gears on more than one occasion, I would like to get the shifter as cleaned up as possible.

 

There is next to no difference between the STi and Spec.B STS. I have a '10 STi transmission and a Spec.B STS from Cobb. The difference between the two shifters is in how the shift boot attaches... nothing more.

 

Thanks!

Makes sense. I'm only on my third day of driving the car. I don't notice any issues with finding neutral. I can see the shifter being different lengths.

I just am gonna use an sti trim ring and get a boot to fit the consol.

 

As for the brake switch I got the auto switch to fit the 08 sti pedal set.

 

So far so good. Going to look into getting cruise to work but if not I'm not to worried.

 

As someone said about how much the swap costs... Well most transmissions are 2500-3500 depending on what you find. I used a non dccd version 7 one. Then it's tracking down all the little parts. I was lucky and had a lot of the parts layin around the garage.

 

I would say unless you have the parts laying around I wouldn't really do this swap. Just for the sole fact you may be able to find a spec b for the same price all said and done or close to the same price. Only good thing over the spec b is with the trans I went with has a front limited slip.

 

 

Main reason I decide to do the swap on my car and not just go find a spec b or 5mt one was my car already had a forged motor, equal length headers and catless up and down pipe, 44mm external waste hate, front mount and a newer sti turbo.

 

If you already have an 5eat car and can get the 6 speed parts cheap then it's not to bad of a swap.

I bought the car with the tranny already swapped in.

The shift linkage is longer on the Spec B than it is on the STI. There's a P/N further up in this thread.

The shift linkage is longer on the Spec B than it is on the STI. There's a P/N further up in this thread.

Absolutely correct, SpecB is longer.

 

I confirmed this when I bought my pre-swapped LGT, PO gave me the shifter linkages ( he had not installed them ). Had them side/side, would say LGT stuff is around 20mm longer than STI.

 

Obviously you can run with it, just puts the shifter arm forward a bit compared to the console.

I seem to remember seeing photos of that somewhere in this thread... the shift lever not quite centered in the surround.

I believe this is the post people are talking about:

 

http://legacygt.com/forums/showpost.php?p=1568782&postcount=145

Here's the part numbers you need:

 

Spec B Shifter Rod: 35041AG020

Spec B Shifter Stay: 35031AG020

More information found here

I don't want to make it seem like I'm trying to push a product, but here is another option for spec.B rear axles.

 

http://legacygt.com/forums/showthread.php/ultimate-6-speed-spec-b-rear-axle-upgrade-group-buy-237940.html

I'm a third of the way through my full conversion to 08 Spec B 6MT and R180. The other 2 thirds are the 6MT and the revised engine.

 

Pulled the 5MT today to find that the ACT HDSS PP had lost a compression tang, so that's why it wasn't shifting. TSK3 looked good, though the TOB was a bit dry. Clutch disk was actually in pretty decent shape, as was the flywheel.

 

Used an air-over-hydraulic trans lift to get the trans out and the whole rear subframe down. Pulled off the steel rear trailing arms (RTA) and upper link and uninstalled the R160. Then installed the Spec B aluminum RTAs, and upper arm, and bolted in the R180 with the WL Rear diff bushings on the rear diff mount and the one open bushing on the front center diff mount. Put in a new differential breather and a new rear cover gasket.

 

Reinstalled the subframe. Everything went in perfectly. Misplaced some of the Spec B hub bolts (which are longer), so wasn't able to reinstall the hubs, nor the rear Spec B axles, because the diff seals the dealership got me are for the front diff and they're too small. Searched the site, and lots of talk about the front diff, but I'm apparently missing any R180 info.

 

Pro tip on reinstalling the rear subframe - leave the subframe sitting on your trans jack, and bolt the bottom of the shocks to the rear trailing arms. That stabilizes everything until you can get one of the front subframe mount bolts started and you then rotate everything slightly to get the front RTA mounts, then the other front SF mount, then the rear SF mounts, and the two bolts in the cross brace all lined-up and tightened-down. You may still have to use a big pry bar to get the RTA mounts lined-up perfectly, but other than that it was actually quite easy.

 

Really appreciate the assist on the R180 rear diff axle seals - 2008 Torsen R180.

Edited April 3, 2015 by SBT
seals...

Couple of quick pics from today as well. Friends who wanted to know more about how a Subaru is put together and how it operates. Father, Son, Grandson. The older guys were very impressed with the simplicity, but also how well it's built and all goes together. The younger boy was more interested in chasing squirrels and killing fires ants...

 

And if you have old tires around, they make a great "table" to work on the subframe bits.

The rear side seal is the same seal used on the R-160. I'm 99% sure you are talking about the side diff seals, not the one that seals at the driveshaft?

Unlike the front diff, it's the same seal on both sides of the rear diff.

OIL SEAL .

This genuine part fits your 2008 Subaru Legacy 25GT-B SEDAN 2.5L TURBO 6MT 4WD .

Stock Code 806732200 ; 806732030

Manufacturer:Subaru

Categories: Driveline and Differential

MSRP $8.40

 

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Edited April 3, 2015 by Sgt.Gator