Transmission mount... OEM rubber or Poly? Options

[Honda93]

My 2001 Z28 6MT is in need of a transmission mount. It sees regular autocross duty now with a mild STP/CAM-C setup. I do not drag race and I haven't been on a road course with it yet, but that may change.

It is driven daily, year-round in NJ.

Would an OEM replacement trans mount suffice, or should I install a poly mount?

I have a poly torque arm mount and the motor mounts are still OEM rubber in case that matters.

What do the experts suggest?

Thanks!

[slowTA]

Get the poly, I've had the same one in my car for over 15 years with no problems.

[StanIROCZ]

I broke several replacement rubber mounts when the car was still stock. Poly has been on my car since 1997 and never failed.

[Honda93]

Get the poly, I've had the same one in my car for over 15 years with no problems.

Thanks guys. Now... Do I have to run poly motor mounts as well or is it OK to continue with OEM rubber for those?

In researching, do I need to shim the poly ones, does it throw the pinion angle off that much?

I'll probably end up buying the Prothane mount.

[slowTA]

Poly trans mount with rubber engine mounts is fine and what I use. Measure the new and old mounts and use the included shim if needed.

[Honda93]

Poly trans mount with rubber engine mounts is fine and what I use. Measure the new and old mounts and use the included shim if needed.

Thanks so much Chris! See you soon!

[Honda93]

Poly trans mount with rubber engine mounts is fine and what I use. Measure the new and old mounts and use the included shim if needed.

OK... Since we're doing the trans mount, does the motor mount have to be OEM for durability reasons, or is there a trusted OEM aftermarket supplier, such as Moog?

[slowTA]

I have cheapy replacements from rockauto, they've held up fine in my autocross only car for 2 seasons and I expect them to be fine for a while longer.

Are your factory mounts falling apart?

[Honda93]

I have cheapy replacements from rockauto, they've held up fine in my autocross only car for 2 seasons and I expect them to be fine for a while longer.

Are your factory mounts falling apart?

Don't know, didn't check them. Jeff and I figured that since the trans mount needs to be done, the old adage of "When in Rome..." applies here.

But in doing some research, the motor mounts sound like they are a bitch to access. Sounds like the AC Compressor and the starter need to come off.

What was your experience?

[slowTA]

My experience... I blew up the small block and did an LS swap. Everything had to come out anyway! But I will say that LS mounts are easier to change then small block mounts.

If they aren't falling apart or allowing the motor to move around too much just leave them.

This post has been edited by slowTA: Feb 24 2016, 11:16 PM

[landstuhltaylor]

My experience... I blew up the small block and did an LS swap. Everything had to come out anyway! But I will say that LS mounts are easier to change then small block mounts.

If they aren't falling apart or allowing the motor to move around too much just leave them.

I put poly engine and trans mounts in when I had everything out of the car. It was a fight to get the motor mounts to line up but it didn't take too long. I would think it would be a massive pain in the ass in the car. The old mounts literally fell out of the clamshells when I removed them.

I also don't think there is much of an increase in NVH with poly mounts, especially with a loud exhaust. That's what I would personally do.

[slowTA]

Right, the LS mounts bolt the rubber to the motor while small block mounts bolt the rubber to the frame. To get the small block frame mounts out you have to fish sockets and wrenches into the frame through the control arm brackets and hope nothing falls into the middle of the cross member.

Either way, I would only change the motor mounts if they're falling apart.