Hey guys so I have a 1999 forester L that I daily and have the normal 200k tranny problems. I want to put a 6 speed in if at all possible. I've been told be some that a pre 99 to 99 legacy 6mt will bot to it without needing to replace anything besides a speed sensor with possible driveshaft length issues. Any thoughts on the matter that could be helpful?

Edited April 22, 20223 yr by OhMyNuggets

There are two different types of six speed - one that’s a different design to the 5spd and is considered the “proper” six speed because of its strength. The other is a split case 5spd with a sixth gear built onto the back of it. 

If you’re after performance the proper six speed is the way to go. The best is from the STi from what I understand. 

As for what you need depending on what box you have, I’ll leave that up to those that are in the know. 

Cheers 

Bennie

final drive ratio of rear diff must match the trans FD ratio.

 

Edited April 22, 20223 yr by 1 Lucky Texan

The Legacy 6MT must be either a JDM or DownUnder (El Freddo?) option...I've not seen one in the US market. I'd make sure I have a reliable source for it and the DIY install. 

The '04+ STI 6MT is a much bigger and $$ swap.

 

Otherwise, any 5-speed from a '97-'00 (maybe a couple years newer too) Subaru that was connected to the EJ25x should bolt up, and have the 4.11 to match your rear diff. 

On 4/22/2022 at 4:05 AM, el_freddo said:

There are two different types of six speed - one that’s a different design to the 5spd and is considered the “proper” six speed because of its strength. The other is a split case 5spd with a sixth gear built onto the back of it. 

If you’re after performance the proper six speed is the way to go. The best is from the STi from what I understand. 

As for what you need depending on what box you have, I’ll leave that up to those that are in the know. 

Cheers 

Bennie

Thanks for the advice. It's really just for highway. I like the gearing already so I don't want it to change since I take it off road alot. I just need a final drive so I'm not at 3500rpms at 70.

The '97-'99 Legacy OB 5-speed will spin more RPMs in 5th. The '96-'99 Legacy GT is an option, but you'd want to double-check its ratios (its FDR is still 4.11) as I don't recall.

From what I read recently the '99+ (phase 2) 5-speeds are better??? But I have 260K on my '98 Forester (and some of that has been turbocharged).

The phase 2 are “better” because the cases are stronger and the gears a couple of mm wider on 1st and 2nd. I can’t remember if they widened 3rd to 5th too. 

Cheers 

Bennie

Thanks guys my ratio is 4.11 too so the legacy gt 5 will work.