Hi all

I've posted previously about a knock somewhere when I go over bumps etc, having now ridden passenger in my car for the first time, I realize it is not the front left, seems to come from the centre, hard to tell though, reverberates in the cabin. However, having been under my car, I noticed the transmission mount was slightly loose, is this right? Should it be able to flex a little like it is? I also ask because the shifter sits high, especially at the rear of the housing. Any chance something could be wrong here? The chap that changed the fluid also has a habbit of not tightening things up... Any thoughts are most welcome.

 

The mount *does* have some springy-ness but design but in all likelihood your 'thimble' cushion is worn out, #3 in this illustration

Gearbox Mounting-5.3 Litre - Parts For Series III Saloon | Jaguar Classic Parts UK


Another possible source is exhaust pipe-to-body interference


The gearshift is mounted to the floor of the car, not the transmission....so there's no relationship

Cheers
DD

 

Ah thanks for clearing that up Doug, again I've learnt something new today.

#3 looks suspect to me too, I'll dive under there tomorrow and have another look. I'm doubting the pipes, the knock is a pretty deep thump, not anything light and tinny. Are these bushes known to go?

 

YES!


Cheers
DD

 

Here ya go.

I wrote this years ago, hope it helps a tad.

Jaguar TH400 transmission mount explained.doc

 

Wonderful, well if it solves my problem that is... I'll poke my head under tomorrow, thanks again Doug!

 

Neither is in my car, but, I just had to look !


Two comments:


1. Yes, I use Libre Office. slick as it gets.
2. GM used a simple rubber block to do the same thing. Seems like
one would fit just right and simplify a lot.


Carl

 

Just read the doco you sent Grant, very useful! Thanks! And it confirms the sound I'm hearing is the UJ clobbering something, an opportunity to stand on it from an inclined stationary start presented itself, and I could hear what you described. Now, the spacers that the service bulletin asks for, do they go between item 9 and the tranny? I've attached the diagram to help.

Many thanks

 

Yep.

I used standard washers from my tin of washers. Nothing fancy needed here.

 

Brilliant! Thanks Grant!

 

Had a look at the mount today... How high can I jack the tranny, I'm scared of bending something... Just wanting to put spacers in, if I undo the 2 bolts at the back and jack the tranny, will it ever come away from the mount? Or do I have to remove the whole thing?
Many thanks.

 

In your dreams Nathan.

That mount bracket needs to come out, which means unloading that spring, and then you can do thw washer thing.

I am still more inclined that thw "Cotton Reel" bush in the centre of that mount bracket is toast.

Greg on FrNCWE Ha done an excellant safe way of unloading that spring. It should be in here, or maybe the XJ-S section.

I will email him to put it here for you when the planets align better.

 

Aha that clears things up! Thanks a lot Grant! Might as well do the whole lot in one shot...

 

Here ya go, from Greg in France.

https://www.jaguarforums.com/forum/x...itting-145478/

 

Thanks a lot Grant, much appreciated!