Transmission mount experiment

Had the car up on jacks for a couple weeks, couldn’t resist removing my transmission mount! Yep, I’m a glutton for punishment.

The diagram for my 1988 shows only one rubber seat for the transmission mount spring, on the bottom. The top of spring fits metal to metal on the transmission.

A few years ago i replaced the bushing with rubber, the spring with aftermarket, and the lower rubber seat. I am 100% sure I aligned it perfectly.

I’ve always felt a faint vibration in my seat at idle now and then.

So I decided to go back to my original spring AND put a second rubber seat at the top of the spring, between spring and transmission.

Just did test drive, pretty sure the vibration is way less, almost gone. Feels much smoother at idle.

I put both springs side by side, the original (left) is a bit taller, but the aftermarket one is a bit stiffer. (See photo ).

Don’t know if it’s the spring, the second seat, or both, but I am definitely glad i experimented!


Did a lot more test driving. Unfortunately the faint vibration is still there at idle, sometimes. But it didn’t get worse with the second rubber seat.

Just gonna chalk it up to using a rubber bushing instead of foam.

I was almost going to suggest since you had them out just to order an OEM spring. Probably just as stiff when new. Might be a little late now that you have it all back together.

Did you use a new oem spring?

I may add it to a list of “to try one day”.

I’m going to have to go back to my original invoice from my mechanic. I will report back.

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I can only assume it was , he always ordered the parts that came in Jaguar packaging usually from Coventry West.

Update! While i had exhaust off to do starter, i installed a new oem transmission mount spring i had bought a while ago.

Glad to report it has helped vibration at idle. (Note, i have rubber bushing)


  • I replaced original spring (which i kept) with aftermarket spring pretty soon after i got car. Always had a little vibration in my seat at idle. I did notice (photos above) that although the aftermarket spring seemed a bit stiffer, it was shorter.

  • decided to put back original spring. The vibration went away, but sometimes I’d feel a pulsing vibration in my seat.

  • bought a new Jaguar oem spring. Same height as original, but a wee bit stiffer. Now the pulsing vibration is at a minimum, barely feel it.

So goes to show, oem or nothing.

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