Word of advice - Dont solid mount your gearbox.

[AlexGSi2000]

For a few months now I have suspected a few worn out engine and gearbox mounts on the 2.5 - there was a little movement from the gear stick when putting your foot down and lifting off.etc

Decided to replace the front snub mount, side engine hydro mounts (which had leaked thier fluid) and the final bush/mount was the rear gearbox support.

I usually like a more "direct" feel and have fitted vibratechnics mounts to previous cars - as there is pretty much nothing aftermarket in the way of mounts, I decided to buy some poleurethane resin mix from ebay and fill the voids in a new rear gearbox mount.

I chose a mix which was pretty solid (ended up setting like plastic) and fitted the mount last night.
Bad descision - its effectivley solid, which transmits all engine vibration through the whole of the car!
The resonation is that bad on idle you cannot hear yourself talk! (May grab a video)

Will be removing tonight to try and remove some of the poleurethane from the bush without destroying it.

 

[BRILLO]

Sounded like a good plan though. You don't know till you try it eh.

 

[AudiLeon]

Drill some holes in it, to give it flex.

 

[DieselJake]

What did you replace the hydro mounts with? I've got RS4 one's to go in but this has worried me a little now as I've heard good reviews but this solid mount talk is worrying.

 

[AlexGSi2000]

I replaced the hydro mounts like-for-like.

I modified the rear gearbox support mount with poly resin - thats where my issue is.

You will have no issues with the RS4 mounts, its just the fact I filled mine with resin made it properley solid. (the RS4 mounts wont be as solid) The one I filled with resin literally resonates the whole car, its pretty nuts.

 

[Paul_A4_UK]

I remember when I fitted some kind of uprated / stiffer engine mount in my Peugeot 306-Gti6, they made the whole car resonate and yours can only be worse seeing as you've made the mount totally solid. I did get lucky that after a while my hard rubber ones softened a little and the cabin buzz disappeared.

Dremel time for you Alex

 

[DieselJake]

I replaced the hydro mounts like-for-like.

I modified the rear gearbox support mount with poly resin - thats where my issue is.

You will have no issues with the RS4 mounts, its just the fact I filled mine with resin made it properley solid. (the RS4 mounts wont be as solid) The one I filled with resin literally resonates the whole car, its pretty nuts.

Cheers Alex, fair play for trying seemed like a good idea.

 

[AlexGSi2000]

Took the mount out last night and removed all the polyeurethane I filled the gaps with.

What a difference - the car is now silent again.
I did question wether the polyeurethane was to blame as the vibration was so severe considering the amount of poleurethane in the bush - as there wasnt much. Guess its designed like that for a reason eh.

May give it another go in the future with a much softer poly - the grade I used was Shore D 72 - a table online compares to the hardness of a builders hard-hat.

 

[desertstorm]

If theres movement in the gearbox stick backward and forward a few mm as you accelerate and lift off that is probably wear within the gearbox itself. Is it more pronounced is 3rd and 4th than 1st or second.