OEM Transmission Mount vs DIY polyurethane

[ROB III]

Do people generally just fill their old mount with urethane or buy a new one and fill that? My trans is flapping in the breeze and the new motor is not going to help that. Was just about to buy a semi-solid mount but Im not keen on the noise, its bad enough without the rear carpet in.

I think most people just fill the original mount with urethane and go with that. I did overkill by buying a new mount AND filling it with urethane as a long term solution/prevention of repeat issue. After seeing Tom's post on how the brackets were cracked on his, I bought a new set on Ebay. That way I could prepare the replacement unit to do a fast swap with the old one. Elastomers degrade so I thought the urethane would slow the degradation and generally stiffen things up a bit, but still allow some NVH isolation which solid mounts amplify. Prior to replacing the rear I had already replaced the engine mounts and felt the upgraded new rear mount resulted in a perception of steadier, more precise response in quick transitions.

[blade7]

I think it may have been early 924's that had an alloy brace, that bolted to the gearbox and the shell. Probably dropped on cost grounds.

[944m3]

Can I ask what your symptoms are?

I have new motor mounts, which helped a lot, but I’m still experiencing some vibration and “wobble” feeling. I’m hoping it’s as simple as addressing the transmission mount, which I’m sure it’s original to the car.

No particular symptoms apart from maybe a bit of jerkyness at part throttle. When I have the car on the hoist you can move the tranaxle a couple of inches side to side with just one hand.

Thanks. I’m starting to think I might need to replace all the rear suspension bushings. It does not look like a fun job.

[ROB III]

I've been thinking to replace all the suspension bushings just due to age of the originals. I don't have a specific issue I'm trying to address just that in looking at many sites with older car updates, all I ever see when the suspension bushings are replaced are positive comments. Part of this is likely due to the owner of any older car doesn't really have a reference point from when their car was new, so they are not aware of the degradation, so changing the bushings will hopefully bring some aspects of handling back to like new condition, particularly if the shocks have been replaced/upgraded.

[944m3]

That’s my thinking as well. When I look under there everything looks pretty old and crusty. So changing out all the rubber can only help.

Plus with the going rate of these cars, I can justify the effort and cost.

[Bergerac]

I think it may have been early 924's that had an alloy brace, that bolted to the gearbox and the shell. Probably dropped on cost grounds.

The 924 transaxle was a completely different design wasn't it? Or was that just the turbo?

[cda951]

Early 931s had the "snail shell" transaxle, which was very similar to the contemporary Porsche 915 transaxle used in the 911, but without a bellhousing.

The later 931 used the same Audi-based transaxle with bellhousing as used in the 944.