I´m getting knocking/rattling noise from the trans mount while driving. How far should be the lower "tongue" from the mount? I find out previous owner already added some rubber between these two part, but even if I push the trans up with hand I can hear the noise. I also have new spare spring from previous owner, but I think with new spring the tongue would be even closer?

 

Never measured that spec ever.

The TH400, your car, only has a rubber seat on the bottom of the spring, as apposed to the BW12 and 6cyl cars, which have a rubber seat top and bottom.

Have a read of the attachment, might clear the mud a tad.

 

Grant, your response comes at the perfect time!

I took apart the transmission mount on my '74 XJ12 under the impression that car was original and unmolested--but it wasn't.

And so when I reinstalled the mount--the way it came apart--it was clear something was wrong. But there is a LOT of information out there on these mounts but what kept tripping me up was the fact that I have TWO sleeves within the bushing. I did luck out because the original friction fit washer was still there.

 

Andy,

The BW12, yiur car, used the same layout as the 6Cyl XK powered cars.

Took me many,many beers to work it all out a very long time ago.

The books I had, no computers, were basically useless.

Glad I could help.