Shift Carrier Rear Bushing: Why you want it soft.

[nrubenstein]

I had the the drivetrain sitting on a dolly, so it was a good opportunity to make this video:


(For those who would prefer to click through/don't have flash installed: https://www.youtube.com/watch?v=z0x296RcDMk )

As you can see here, the only thing that a stiff rear bushing is doing is creating an opportunity to break something. It does nothing/next to nothing for shift precision. So stay away from them, unless you really want to create situations where your whole drivetrain is pivoting on the carrier mount.

[Northern]

I had the the drivetrain sitting on a dolly, so it was a good opportunity to make this video:


(For those who would prefer to click through/don't have flash installed: https://www.youtube.com/watch?v=z0x296RcDMk )

As you can see here, the only thing that a stiff rear bushing is doing is creating an opportunity to break something. It does nothing/next to nothing for shift precision. So stay away from them, unless you really want to create situations where your whole drivetrain is pivoting on the carrier mount.

Fixed your vid :p


Do you have any reason to say that it will cause an issue? I've never heard of anyone with issues with solid front and rear bushings.

[groupus]

/\ I'd have to agree, I can't think of why firmer mounts would be more prone cause problems. It looks like your front carrier bushing is stiff enough in this video to not allow it to move around. But why would you not want two good point of contact for mounting the carrier? Without a stiff rear bushing, you will wear the front bushing quicker. Then you will have issues.

I got under my car recently to investigate sloppy linkage and found that the rear carrier bushing was all but useless. This, coupled with a worn out stock front carrier bushing, allows the carrier to move side to side, along with the shift lever. I'm going to replace them with dilrin bushings, as well as all of the other stock bushings.

[TobyB]

If the engine is mounted solidly, you can solid mount the shifter at both ends.

If the engine has rubber mounts, or softer urethane,
and the shifter bushings are all solid, then
the shift carrier can become the load path
to the body for motor/trans movement.

The rear bushing should be 'firm', but a bit of movement there isn't going
to detract much from feel, especially if the shift carrier's solidly attached
to the trans. It's really just holding up the back end of the carrier.

It's the only non- delrin/stiff urethane mount on the Pro3 car
for exactly that reason- it doesn't matter much if it's not absolutely stiff,
but if it binds solid, it will break the rather lightweight rear mount off the
body, and that WILL suck...

t

[nrubenstein]

/\ I'd have to agree, I can't think of why firmer mounts would be more prone cause problems. It looks like your front carrier bushing is stiff enough in this video to not allow it to move around. But why would you not want two good point of contact for mounting the carrier? Without a stiff rear bushing, you will wear the front bushing quicker. Then you will have issues.

I got under my car recently to investigate sloppy linkage and found that the rear carrier bushing was all but useless. This, coupled with a worn out stock front carrier bushing, allows the carrier to move side to side, along with the shift lever. I'm going to replace them with dilrin bushings, as well as all of the other stock bushings.

You want the stock rear bushing because a super stiff rear bushing ties the engine and the transmission to the chassis through a dinky aluminum carrier and small tabs on the transmission.

It's not about shift feel. And Toby is completely correct - if the engine and trans are solidly mounted, go for it.