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#Rebuild factory 5MT or swap in another 5MT?

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 Post subject: Rebuild factory 5MT or swap in another 5MT?
PostPosted: Sun Jun 18, 2017 12:25 pm 
First Gear
Joined: Wed Apr 10, 2013 6:43 am
Posts: 216
Location: Key West, Florida
I have a 1993 Subaru Legacy Sport Sedan

Assuming the factory transmission. What's easier? Cheaper? Stronger? I will research costs, but want to understand my options. This is to be done on a tight budget, so I'm looking for easiest way to get the strongest possible factory 5MT in there or rebuild original with strongest possible parts for a comparable cost. If at all possible, I want to keep factory final drive ratio of 3.90 to eliminate need to replace rear differential, and I'd like to keep the relatively high 5th gear for highway fuel economy. Please correct me if I'm wrong, but according to Wikipedia our transmission's gear ratios are as follows:

Gear Ratios: 1st 3.785 2nd 1.945 3rd 1.500 4th 0.994 5th 0.780/(0.735 WRX) – Final 4.11 (3.90 WRX)

Usage: All 1990–2003 with EJ-Engine

I hear that the Legacy GT transmissions from 2005 up are the way to go for cheapest / strongest factory transmission, but final drive is different. Also, clutch changes to pull type.

Can't factory 5MT be rebuilt with Legacy parts while leaving front differential ring and pinion alone? Might swapping in a good used Legacy transmission and rear differential be simpler and cheaper? How big a deal is the switch (if necessary) to pull type clutch?


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 Post subject: Re: Rebuild factory 5MT or swap in another 5MT?
PostPosted: Sun Jun 18, 2017 7:19 pm 
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Joined: Tue Aug 25, 2009 7:52 am
Posts: 4490
Location: Des Moines, Wa
I vote for a modern used transmission swap. The much improved syncro design makes the new stuff a joy to shift. I used a Forester Xt trans. It has tall gears with a short final drive. I think the effective gear ratio are equivalent to the 05+ legacy GT.

I've also used an 03 WRX transmission. It had long gears with a long final drive. Very similar to the stock SS, but with vastly improved shift quality due to syncro design. Unfortunately most of those were beat to shit by punks over the years, and mine was no exception.

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1992 Legacy SS 5mt, reasonably modified ;)


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 Post subject: Re: Rebuild factory 5MT or swap in another 5MT?
PostPosted: Thu Jun 22, 2017 7:03 am 
First Gear
Joined: Wed Apr 10, 2013 6:43 am
Posts: 216
Location: Key West, Florida
Does anybody know for sure if the following information is accurate?

1990-1991 Legacy

MT
1st: 3.545
2nd: 1.947
3rd: 1.366
4th: 0.972
5th: 0.738
Rev: 3.416

FWD: 3.700
AWD: 4.111
Turbo: 3.900 (Note: Turbo model was only available in the 1991 MY)

AT

1st: 2.785
2nd: 1.545
3rd: 1.000
4th: 0.694
Rev: 2.272

FWD: 3.700
AWD: 4.111
(Note: I'm not sure if the turbo model was available in AT in the 1991 MY. If it was, the final drive ratio would be 3.900)


1992-1994 Legacy

MT
1st: 3.545
2nd: 1.947
3rd: 1.366
4th: 0.972
5th: 0.738
Rev: 3.416

FWD: 3.700
AWD: 4.111
Turbo: 3.900

AT

FWD

1st: 2.785
2nd: 1.545
3rd: 1.000
4th: 0.694
Rev: 2.272

FWD: 3.700

AWD

1st: 3.027
2nd: 1.619
3rd: 1.000
4th: 0.694
Rev: 2.272

AWD: 4.111
Turbo: 3.900


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 Post subject: Re: Rebuild factory 5MT or swap in another 5MT?
PostPosted: Thu Jun 22, 2017 12:41 pm 
First Gear
Joined: Wed Apr 10, 2013 6:43 am
Posts: 216
Location: Key West, Florida
Also, could I just as easily go with a modern N/A transmission, or does the fact that a transmission comes from a turbo car make that much of a difference? Which came with hydraulic clutch?

Finally, if I do finally retrofit a newer trans, how hard is the switch from push style to pull style clutch? What parts will I need to replace?


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 Post subject: Re: Rebuild factory 5MT or swap in another 5MT?
PostPosted: Thu Jun 22, 2017 3:46 pm 
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Joined: Tue Aug 25, 2009 7:52 am
Posts: 4490
Location: Des Moines, Wa
You can easily swap in an NA trans, you just need the application specific clutch kit, fork, slave cylinder and line that goes between master and slave.

If you do a search for Alphius's post on retrofitting a newer turbo clutch kit with an NA trans, then you could have a better clutch while having OEM-smooth clutch actuation (compared to a heavy duty uprated NA clutch kit)

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1992 Legacy SS 5mt, reasonably modified ;)


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