Mach 1 Club

Hi Folks,
I thought I'd pass on mine, and my sons experience with polyurethane gearbox mounts.
Given that my 351 C is putting some decent horsepower, I thought I'd better fit new mounts to my FMX to cope with the stress - so I fitted a polyurethane gearbox mount.

I suddenly developed a nasty vibration at 50mph; but only 'on' power, never on over run. After checking every possible fitting, nut and bolt on the drivetrain, we fitted a stock rubber mount. The vibration was gone.

A couple of days latter the original gearbox mount on my son's 66 fastback broke. Not having a spare genuine mount - Alex bolted in the polyurethane g/box mount to his C4. The vibration was so bad -he was worried about breaking his engine mounts or his exhaust hangers. Alex bought and fitted a stock mount next day - the shakes were gone!

I was about to buy a pair of polyurethane engine mounts, but not now. I have heard lots of classic car owners say much the same about polyurethane suspension parts - but I never truly believed them. I'm a believer now!!

I enclosed a link to the mount I fitted.

http://www.ebay.com.au/itm/1965-1973-For...3f1a4d5a63

Good info!

Definetly sounds like something to avoid. Sometimes the old addage you get what you pay for is true. not everything on Ebay is good stuff. JTS 71 Mach1

Good info!

I think polyurethane has it's place. I only use it on sway bars and body mounts, seems to work good there for me. I have never tried it on higher torque applications such as motor mounts and tranny mounts.