Just a question if I get new aftermaket transmission mounts would I accentuate the case flex in my transmission? I drive an 03 5spd Sedan.

Edit: Ok did a search, I know...should of done that first, but after reading the threads I'm gathering that the mounts actually help decrease case flex since they are not as compressible, helping keep the transmission in one place, correct?

Thanks,

Jason

 

Correct. Also getting engine mounts and tranny mounts at the same time have a larger effect on case flex than just tranny mounts...

 

Actually, I think a tougher tranny mount would contribute to the case flex. If the mount doesn't flex, somethign else will.

 

Not dumping the clutch or powershifting will help more than any mods.

 

That's what I was thinking, but I try not to abuse my clutch, so far no problems. Also I am getting the engine mounts at the same time. Trying to do some stuff to my car before the Subaru track day.

Jason

 

Righto Chap!

-Gagan

 

Really? I guess I had it wrong, damn, I'm sorry... I thought case flex was when the tranny essentially twisted in its mounts in relation to the engine when under high torque loads. So when it twists things become slightly out of alignment and that's not really the best situation when you're under a high torque load. Anyway anyone wanna clarify exactly what case flex is then? From how you all are talking about it, it sounds like it's the actual metal case itself flexing under load. Guess that would explain the name "case flex" huh?

 

So do the stiffer mounts help or hurt the car?

I understand the idea of how if the mounts don't flex than something else will. But how can a rigid structure with a rigid support move if it's movement is restricted. I would really like some clarifying on the issue also.

 

The case is aluminum. It is held together with rather skinny low-grade bolts. So, the "halves" of the tranny flex in relationship to each other. Thats how it flexes.

I have heard first hand stories of high horsepower WRX's litterally split apart cases under power.

The 6MT has a cast gurdle that holds the tranny halves together. That, plus much stronger aluminum casing of the 6MT makes it THAT MUCH stornger, that I am yet to hear about a single 6MT tranny "just blow up" like the 5MT's do.

My take on engine/tranny mounts has changed since I starting modding my Subaru's (GC8, SF5, BE5, GDA). At first, I liked them, as they gave me a "nice feeling" of my car. However, there is absolutely to performance advantage of running hard mounts. The make the car vibrate with the engine, rattling your teeth out of your mouth. The car will be noisier, rattlier and generally less comfortable.

At some point I had CUSCO motorsports busings in and I took them out. At this point, I am running STi engine and tranny mounts. However, I will swap in the stock mounts soon, since with my car being too noisy and generally racecar-like, I don't need anything that makes it even worse with no performance benefit.

 

I will 2nd this.