IW STi Forum banner

1 - 20 of 32 Posts

·
Registered
Joined
·
717 Posts
Discussion Starter #1
I'm using a gear oil (idemitsu racing 75w90) recommended by DysonAnalysis based on a couple samples, and we're not seeing any abnormal wear in the trans; however, he seems to think that my trans should be shifting smoothly when it's not. I'm on my second fill of this fluid, and I think I got all but 0.2 qts out of the last drain, so I don't think that any significant amount of HPGO is still in there.

I don't feel that it's ever been easy or smooth to shift into gear across 54k miles (I bought it new with 100 miles). For example, getting into 2nd & 5th gears for the first time each morning has a crunchy feeling. It just doesn't seem to want to go through the gate very easily, and double clutching will only sometimes aide in that.

I am curious if that's something that can be resolved with bushings or trans mount or anything like that, or maybe has to do with the dealer installed short shift kit?
 

·
Registered
Joined
·
250 Posts
I have 17K on my '17.


I replaced the factory trans fill at 15K.
I used Motul gear300 as recommended by folks on this forum.
Change from factory fill seemed to do nothing in my opinion.



Mine still has the light crunchies into 2nd gear if the trans is cold-ish and the ambient tempsare below 50ish degrees.


Weirdly many times the 2nd shift into 2nd is worse than the first.


When warm the shifts are good.


I believe it also has to do with the rev hang of the engine (holds engine RPM) when cold.



I have found no solution to the cold issue.
 

·
Registered
Joined
·
467 Posts
Got 70000KMs and also tried using Motul Gear 300 to help with shifting. I didn't see any change. In cold Canadian winters I can't even get into 2nd for the first 1-2 minutes of driving. I think it's just how these transmissions are. You can look into 'cocktails' for these transmissions but that may do more harm than good.
 

·
Registered
Joined
·
112 Posts
I have the same issue with my 18. I have not changed fluid, but I had an RX8 that shifted so hard I bought a rebuilt trans for it. Tried fluids first, with redline it was worse. Club forums suggested Eneos 75/90 so I figured what the hell. Drained the redline and pumped in Eneos and before I even moved it I knew it was better. 45000 miles and it now shifted like a new car. Very tempted to try it in the STI. I know, vastly different gearbox but results are results.
 

·
Registered
Joined
·
31 Posts
Trans mount and positive shift kit made of world of a difference in my car (2017 STi). My trans mount is a solid IAG and white line positive shift kit.
 

·
Premium Member
Joined
·
5,202 Posts
I'm using a gear oil (idemitsu racing 75w90) recommended by DysonAnalysis . . . he seems to think that my trans should be shifting smoothly when it's not.
. . .
I don't feel that it's ever been easy or smooth to shift into gear across 54k miles
. . .
I am curious if that's something that can be resolved with bushings or trans mount or anything like that, or maybe has to do with the dealer installed short shift kit?
You experience is normal as you can see from the replies. It's a Subaru, it will shift like one. The different WRX/STIs have all had issues at times when when downshifting, and in general when cold. Others may report differently. I've seen it here. Drive those cars. They won't be any better.

Why would an oil analysis guy try to tell you how your car should shift from an oil analysis? There are so many other things at play here.
 

·
Premium Member
Joined
·
809 Posts
the STI 6MT is better than other Subaru transmissions for sure. They take a while to loosen up I think. Mine started to shift less clunkily after 30k or so.
 

·
Registered
Joined
·
44 Posts
MY18 STI tranny is disappointing to me. I listened to too many fanboys talking up the tranny over the years.

I've put 70,000+km on and it's not confidence inspiring, worse over time. Shakes in idle, shakes in gear, knotchy rubbery all year round -30 to +30 in Canada.
 

·
Registered
Joined
·
717 Posts
Discussion Starter #9
MY18 STI tranny is disappointing to me. I listened to too many fanboys talking up the tranny over the years.

I've put 70,000+km on and it's not confidence inspiring, worse over time. Shakes in idle, shakes in gear, knotchy rubbery all year round -30 to +30 in Canada.
Are you talking about the shifter itself shaking? It's a solid connection between the shifter and the mechanism in the transmission, as opposed to a cable. So if the transmission and engine are shaking (say at cold idle with stock engine & trans mounts) then the shifter will move about while in neutral.

If you want to minimize that shifter movement, you could install more solid mounts for the engine and trans, and maybe even the shifter linkage too. The drawback would be more noise in the cabin.

Here's a video from an iwsti.com member showcasing really bad shifter movement: Possible Cracked Transmission Mount Diagnose 2015 WRX STI - YouTube
 

·
Registered
Joined
·
467 Posts
I put on a group n transmission mount and its one of the best mods I've done. It's way more accurate and precise and doesn't increase NVH much at all. Doesn't move around when you accelerate anymore.
 

·
Registered
Joined
·
717 Posts
Discussion Starter #11
I put on a group n transmission mount and its one of the best mods I've done. It's way more accurate and precise and doesn't increase NVH much at all. Doesn't move around when you accelerate anymore.
Did you do engine mounts as well? Or are those still stock?
 

·
Registered
Joined
·
467 Posts
Did you do engine mounts as well? Or are those still stock?
Engine mounts are stock. I also changed the front and rear shifter bushings but they created a lot more NVH after I put them in. I have heard changing only the front shifter bushing doesn't increase NVH but makes the shifter feel more accurate.

I'd recommend doing only the group n transmission mount because its pretty cheap (Like $80 CAD) and really easy to change.
 

·
Premium Member
Joined
·
809 Posts
I have read, and can verify, that if you're going to change one engine/tx bushing, you should do them all. Pitch, engine and transmission. It works as a system.
 

·
Registered
Joined
·
717 Posts
Discussion Starter #14
I have read, and can verify, that if you're going to change one engine/tx bushing, you should do them all. Pitch, engine and transmission. It works as a system.
I was thinking the same thing. That being said, the Group N is one of the softest aftermarket options, right? So he might be fine without swapping engine mounts too. It'd be far worse if he changed the tx bushing to a Beatrush or Perrin mount.
 

·
Premium Member
Joined
·
197 Posts
The shifter requires positive input.
In a Honda, wave at the gearbox and it complies. Not the Subaru.
10lb solid lead shifter knob will smooth it out.
Or the eco friendly 12lb solid gold shifter knob.
Or the bipartisan 2lb stainless knob can help you through shifts in the morning when you feel most feeble. Recommended by Mr. Burns...
I use the Armstrong method. All the time.
 

·
Registered
Joined
·
467 Posts
In general the Subaru shifter is not the best and the notchy feeling will most likely always be there. With front and rear shifter bushings and the transmission mount it feels pretty nice tbh. I tend to like the more notchy mechanical feel of it. As RocketRobin said maybe try a heavier shift knob.
 

·
Registered
Joined
·
560 Posts
The STI shifter felt like a truck shifter compared to the Honda. It always feels two step when shifting it into gear. But it is a strong gearbox and maybe it has got something to do with it.

I personally do not mind it, in fact I enjoyed it but yeah it isn't Honda slick.

The only way to slot it into gear during downshift in one swift movement is to double clutch it. When its done right it feels very rewarding. At least it feels very fun to me as I like rowing through gears when I am driving.

Having said that, I swapped my shifter to STI short shifter, add brass pivot shifter, aluminium front bushing, titanium u-joint bushing and the kartboy rear bushing - though I wish I bought Group N rear bushing instead.

Oh and I have the optional STI leather gear knob shifter.
 

·
Registered
Joined
·
717 Posts
Discussion Starter #19
The STI shifter felt like a truck shifter compared to the Honda. It always feels two step when shifting it into gear.
Thank you for putting into words what I couldn't. That's been my experience exactly, but no problems yet after 55k miles and I've had a couple great UOAs on the trans fluid.

I'm shopping around for shifter bushings and other things, but I'm already heavily leaning towards the Group N solutions.
 

·
Registered
Joined
·
560 Posts
Ya I mean that is how the shifter is. It is not an issue.

You will not be able to change its shifting motion, but you can make it more precise but that too comes at a cost of increase NVH (Kartboi front and rear PU bush).

And also the first and second gear is more like straight cut gear than helical so you will hear the gear whine if you replace the soft oem bushing. That is why oem shifter will wobble about during hard acceleration and you need to also remember the shifter isn’t cable link. Since the bushing is soft yet the shifter gate is notchy, it makes a strange rubbery non precise feel.

Another thing that I can say is, on race circuit that 2 step shift motion actually feels natural to the car. I don’t really understand why but maybe because it is AWD so I have to be patient with the clutch anyway. I mean, comparing it again with Honda’s slick shifting device which really help to keep that rpm boiling; it suits the nature of the car. Not sure if that makes sense?
 
1 - 20 of 32 Posts
Top