legacycentral bbs

what are the limits of the SS 5mt?

I grenaded 2 in 9 months with a 16G and supporting mods. 1 went pushing 16psi the other at 14 psi.......

Probably around 220 whp/ 250 wtq were my numbers at 16psi.

Oh, and I was running a SPEC stage 1 kit. It had a 2800lbs pressure plate so, that could have contributed to the demise of said trannies.

I have a 16g and am at 220whp, and am running a centerforce dual clutch.

It is still holding.

But the synchos for 2nd are running thin

It has a lot to do with how you drive it as well. If your rolling into boost and not bang-shifting it, it should last a long time.

All driving...


I never broke one...with VF39 at 20psi

Just to make a note. While driving properly on one will make a difference, there are plenty of reports of people, including Phil I believe, who've broken gears just pulling into the groccery store parking lot and such - aka non-abusive situation.

Yeah, my first went when I rolled into boost nice and slow in second. as soon as it hit full boost, BANG!!!!! it was toast, almost the worst noise imaginable....

Second tranny went in 1st when not even under boost and I was babying that tranny because of the first, lower boost level and all.

if i were to swap in a wrx 5mt is there a way i could keep the 3.90 lsd in my '91 ss? and what would the limits of that transmission be?

^ Get a 3.545 ring and pinion set.

Don't some WRX trannys have a 3.9 FD?

They do have a 3.9 final drive. However, they have a 1.1:1 transfer gear set requiring a 3.545 rear diff.


The limits of a stock WRX tranny will vary. It all depends. Some blow them at stock levels, others hold at 300whp. It all depends.

^ Yup, meaning ALL USDM WRX trannys need a 3.545 rear. And it all depends on driver if they hold. Guys make 350whp for years, and others blow them on stock power.

The 02-03 WRX trannys on Nasioc are refered to as Glass Trannys, because they were supposedly update in 2004 to stronger internals.

And yes, stock Legacy Turbo trannys arent necessarily week, but I had one go for no aparent reason. So it is in the driving but not ALL in the driving.

Mine went during a 2nd gear roll-on leaving the gas station @ ~20 psi . However, I did abuse it for months before. I wasn't surprised or mad.

One other note about the WRX 5MT.

You CAN use it with your stock rear end if you swap out the tail shaft (this includes the transfer gears) for one from any other Phase 2 5MT. Every other subaru 5 speed has 1:1 transfer gears.

Much easier than replacing the 3.545 R&P in my opinion.

My SS tranny died at 120K miles. Previous owner left the car stock, and it destroyed 2nd gear.

smh0101 wrote:The 02-03 WRX trannys on Nasioc are refered to as Glass Trannys, because they were supposedly update in 2004 to stronger internals.

And yes, stock Legacy Turbo trannys arent necessarily week, but I had one go for no aparent reason. So it is in the driving but not ALL in the driving.

All true. This is why you don't want to buy an pre 04 WRX 5MT, if it breaks the older parts aren't available and the updated parts you will need to buy will make the rebuild much more expencive than if its and newer one. I've had a few customers shocked at the repair bill for say a blown 2n't gear because of all the updated parts needed. I've also seen lots of people who like to slam gears hard blow up stock tranny's (mostly 2nd gear and 1-2,3-4 synchros) in 10k miles. But a parts guy at my work runs 20+psi on the WEAKER tranny in his 03WRX daily and has had no problems for 65K miles.

I destroyed my first trans *2nd gear* when I was drifting my car, wearing a six puck non-sprung clutch... (YUP, didn't really understand what I was doing at the time to my poor gears)

Second time was me flipping through the gears quickly, but with a stock clutch and a high performance ACT pressure plate. It lasted well, up until that point...

I'm running Urethane engine/trans mounts, TD04 turbo, intercooler, stock ecu... with a short shifter. *230HP?*

I'd say, little to no probs; driving with smooth take-offs, but it's life is a candle being burnt at both ends with harder driving...

I'm going to reassemble my trans with a good gearset, but this time use stock clutch/pressureplate combo and drive like a normal human until I can afford the six speed swap...

Oh, and I hadn't mis-shifted either time, my synchros are pretty... however every damned tooth was gone from both parties that make up the second gear action

231,000miles on mine, and the sincros are going. hey its had a good run. i beleive with a ra gears set tranny will last.

Airgne wrote:231,000miles on mine, and the sincros are going. hey its had a good run. i beleive with a ra gears set tranny will last.

Ive been starting to look at RA gear sets because my transmission wont last long being mated to a built DOHC 2.5L and man are they spendy.

I may end up swapping in a WRX gearset and see how that holds up.