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6MT Master Swap Thread


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Front diff and center diff are totally different. He was asking about adding the front diff to the Spec B trans, which is totally doable. DCCD = driver controlled center differential. I have read mixed comments on running an STI center diff without a DCCD controller.

 

I'm running an 11 STI trans with DCCD. I haven't adjusted the DCCD setting much yet but I can definitely feel the front diff working when cornering hard, even on winter tires :lol:

 

Also, the taller 6th gear the Spec B has would be good for highway cruise, but I really like the ratio going from 4th to 5th on the STI 6-speed (07+). I think my new 5th gear will be a blast on the road course compared with the LGT 5MT 5th gear -- I was exceeding 4th gear mph at RA.

Edited by Th3Franz
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Thanks Franz. I just did some reading and wrapped my head around the 2 diffs a bit better. Adding an LSD at this time would be ~$1100. Adding an LSD at a later time would be somewhere closer to $1700 or so, so it saves about $600 to do it now. It's a lot of cabbage anyway you swing it, on top of what's already a fairly expensive endeavor.

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Not currently in stock :(

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The 6MT case for the Spec B is different than the STI one. There are holes on both sides of the case, the passenger side one is for the DCCD control, which the Spec B does not have and the STI does. I posted pictures here a while back. You can see the physical difference on your Spec B box.
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You might also look at a Quaife ATB center diff rather than upgrading to the STI DCCD. Unsure whether that's the way I'd want to go, but it's one alternative versus a full DCCD conversion on your Spec B box. Believe KleinerBlaster posted info on this at one time.
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Front diff and center diff are totally different. He was asking about adding the front diff to the Spec B trans, which is totally doable. DCCD = driver controlled center differential. I have read mixed comments on running an STI center diff without a DCCD controller.

 

I'm running an 11 STI trans with DCCD. I haven't adjusted the DCCD setting much yet but I can definitely feel the front diff working when cornering hard, even on winter tires :lol:

 

Also, the taller 6th gear the Spec B has would be good for highway cruise, but I really like the ratio going from 4th to 5th on the STI 6-speed (07+). I think my new 5th gear will be a blast on the road course compared with the LGT 5MT 5th gear -- I was exceeding 4th gear mph at RA.

 

Yeah - thanks for clarifying that so well. I didn't realize that some were confusing the front LSD with the DCCD.

 

The perfect gearing IMM, would be 05 LGT 1st and 2nd, STI 3rd and 4th, and Spec B 5th and 6th, working through the DCCD and front LSD.

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That is correct. Good "to-speed" representation graphs here

 

I just like the 05 LGT 5MT 1st and 2nd better in that mix. All else equal, the Unicorn will ultimately outrun both the 2008+ WRX, the 07+ STI and an MS3 6MT.

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Yeah that's the thread I knew I saw just couldn't search for it at work. Overall I'm pretty happy with the spacing between the gears on the spec.B 6spd. My ultimate transmission would be 07 STi with spec.B 5th and 6th. However I have no real reason to spend that kind of money when I have a Miata that will be cheaper and more fun on the kind of drives that would really benefit from those changes.

2003 Baja 5MT

2016 Outback 2.5i Premium w/Eyesight

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Does any one know when the switch from 12 to 8 bolt front differentials happened? Or more specifically, will the 12 bolt front diff I have from an 08 sti fit my 09 spec b? Edited by Bioya
Fixed 11/12 bolt typo.
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12-bolt was on USDM 04 (and previous JDM Revs) and some 05 STIs. 06+ STI have the 8-bolt. Your Spec B needs the 12-bolt. First I've heard about 11-bolt, or my drug-addled thinker is taking hits.
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I meant 12 bolt. I have a front diff that was sold to me as being from an 08 sti with 8k miles. It has 12 bolts. So it should fit. Just makes me a bit leery that it was misrepresented. I doubt it, but is there any way to check a diff out of a car?

 

http://legacygt.com/forums/attachment.php?attachmentid=124361&d=1343436420

Edited by Bioya
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I don't see a part number anywhere on it. I was told it had "8xxx Total miles" The only marks on the whole unit I see are a small electro-penciled "E" on the side of the body, and a scribe mark that looks like it was used to keep track of the two halves when it was taken apart. Not giving me the warm and fuzzies. And after looking harder, under the ring gear side end bearing, there is a, X 5 V 2 all separated from each other by 90* Edited by Bioya
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  • 2 weeks later...
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Best way to remove the neutral sensor switch? I figure just throw a wrench on it and take it off, but sometimes I screw things like this up :redface: It also looks like it might just get unplugged, but I'm trying not to pull on it very hard if that's not the case...

 

Thanks in advance again. Trans swap is scheduled for early December now, so just need to get the last few things in order :) I am excite!

"Bullet-proof" your OEM TMIC! <<Buy your kit here>>

 

Not currently in stock :(

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If it doesn't turn with a decent, steady pull on the wrench, then put a small flame (propane torch) to the trans case around the threads. Usually will loosen up any "sealant" that may have been used.
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Both of mine came out with a end wrench, and a firm smack with a dead blow hammer. Not too bad, just don't use brute force. From what I understand the LGT and STi switches have reversed polarity from one another? Or at least I thought I read that somewhere.

 

Also, quick update on my situation. I figured out my clutch situation. The new master cylinder I had gotten, was 5/8 diameter, not 11/16 as needed. This meant I wasn't getting enough fluid displacement into the slave to fully actuate the clutch. That being said, I actually used the master from a 2011 wrx, and it bolted right up and works beautifully. Everything feels great.

 

Got the DCCDPro wired up and, functional(i think). I say I think, because when in auto mode, I have not seen any output from the LED on the manual/automatic switch. Can anyone weigh in on this and shed some light on exactly how this should look during everyday driving? I thought it showed varying brightness based upon the output to the center diff? In any case, the manual mode works just fine. I switch it over to manual, dial it up to fully locked, and it bucks like a mule when I try to turn on dry pavement at slow speed. Anyone have any thoughts on the automatic mode?

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Best way to remove the neutral sensor switch? I figure just throw a wrench on it and take it off, but sometimes I screw things like this up :redface: It also looks like it might just get unplugged, but I'm trying not to pull on it very hard if that's not the case...

 

Thanks in advance again. Trans swap is scheduled for early December now, so just need to get the last few things in order :) I am excite!

 

If it doesn't turn with a decent, steady pull on the wrench, then put a small flame (propane torch) to the trans case around the threads. Usually will loosen up any "sealant" that may have been used.

 

A steady pull? An impact is best way to remove stubborn fasteners. I recommend putting a good quality box wrench over the sensor (6 point if possible) and hitting it with a sledgehammer. The plugs are small, so they will fit through the box end of a wrench.

 

The sensors were never a problem on 3 transmissions I removed them from. Just a box or open ended wrench, maybe a light tap of hammer, don't remember - never gave me grief.

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Thanks,

 

I am in the middle of a re-tune and I did not want it to effect the end result. Is the length of the harness of each nss the same? I am assuming the plugs are identical.

KC did you ever swap over the sensors? The 6MT swap I got from Zorro doesn't have the NSS wired up and CC won't engage.
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