So, I've been hearing (and feeling) definite clunks from under the car when going over sizeable bumps, the sort large enough to unweight the car then weight it again. I thought it might be the rear shocks, even though those were replaced recently. So when she was on the lift recently getting an oil change, I took the chance to have a look around. The rear shocks are fine--no sign of the bump stops wearing at all. However, the transmission mount bush looks pretty parlous, and pushing up on the driveshaft and letting go results in a clunk. You can see what I mean here.


This looks pretty nasty....


Yep, pretty rotted away.


Ker-thunk!

This very helpful post suggests a number of parts are needed, which should not be too hard to find, but I'm not sure if those parts are straight-six only.
British Parts Place has got the whole set for US$199, but they say it's for the 4.0 litre. Looking up MHG7566AA, British Parts UK also says it's for the straight-sixes. Is the transmission mount different for the sixes vs the twelves? It looks like the sixes use the MHG7566AA foam thing while the twelves use CAC3227, the central mounting spool bushing. The parts diagrams shown on Jaguar Classic Parts are quite different for MHG7566AA and CAC3227, but I'll be damned if I can find the full transmission mount parts list on the site. It's not under Transmission that I can find, for example.
JagBits has a set for the V12, for rather less than the six. It contains a spring, spool bushing & cups. Is that all I need? The three parts shown in this diagram?


Any advice and corrections will, of course, be most welcome.

 

This is the correct kit for your V12 XJS
https://www.jagbits.com/product/CCC6759-KIT.html

 

Didn't expect to get an answer from one of the actual vendors. Thanks.

 

That diagram and part numbers are the V12 ones. The diagram is from Jaguar's parts website (It comes under the "Engine" section). See here:

https://parts.jaguarlandroverclassic.../brand/jaguar/

Good luck

Paul

 

The engine section! Gargh! No wonder I couldn't find it. Thanks! (I did look there, but I guess I was too focused on "transmission" to register "gearbox"....)

 

Recommend this method for easy and safe R&R from Greg in France:

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

 

I admit to finding that a bit confusing. It looks like Greg's just lowering the bracket, not removing it. Won't it have to be removed to replace all the bushings and stuff? No, wait, forget that. Duh. Of course you remove it. That's just to allow the spring to decompress safely. And to reposition it perfectly. That looks like a good reason to use it even more than the springs thing. The question is, however, where I can get 3/8 and 5/16 UNF threaded rod. Is it worth importing some from the States? Since I won't have the time or space to do this myself, the garage will have a jack or could even (probably) support the engine from above.

This site also has some very good hints and photos. I've run it through Google Translate for you, so there are some idiosyncrasies, but you can get the idea.

 

The spring isn't that strong, I'd support the rear of the transmission with a jack or similar and then remove the mount.

 

Yeah, the U-shaped block of wood to support it with the jack as you undo the bolt seems a good way to go.
I suppose it wouldn't hurt to replace the spring as well....

 

I have had this done in my AJ16 recently. Same type of over engineered mount. It took them, with my direction, 30-40 minutes to do They had to compress some parts on their machine. Unless you really know what you are doing , I would recommend you take the instructions and let your shop handle it.

 

Oh, definitely. I don't have the ability to jack my car up, and even if I bought a jack (easy enough) I cannot think where in my small Japanese apartment I could possibly store one. Not to mention having to cart all the tools to the carpark. Yes, this is definitely a job for the professionals.
Still, less than an hour isn't bad. Probably more for the V12. I have no idea what their hourly labour charge is, though. They just pluck figures out of the air as far as I can tell.... (Which is standard over here. I've never had a shop give me a labour charge by hour breakdown.)

 

In some ways I'd rather than the shop quote by the job rather than by the hour, they should have a good idea of how long it will take. The springs don't seem to be a "consumable" part, but if you do buy a kit that has it you might as well use it.

The only difficulty of V12 vs 6 cylinder mount is in the article you linked you can see how 2 of the mount to body bolts are obscured by the exhaust on a V12. Just means that a typical ratchet and socket can't be used, instead a wrench needs to be use so it takes slightly longer.

If you can't fit tools in your apartment the obvious solution is move (countries if necessary) to have a nice large well equipped shop!

 

Oh, you don't know how much I want to move! Residences, not countries. I go online looking for real estate and searching by "land area" to see how big a garage I could put on it. It'll happen one day, definitely. But persuading my wife to move to a rural or even semi-rural location will be nigh-impossible.... Incidentally, houses with actual garages are rare in Japan, not least because it increases your property taxes. Car ports and other "temporary" structures aren't taxed, but permanent, walled structures are. And for most people, the car is just a tool.

And yes, I can see where charging by the job rather than the hour means there's not incentive to pad hours. And the labour charges seem, for the most part, pretty reasonable. Though I definitely think I should start changing my own oil, as they use Motul for about $20 a litre, and if it's all going to leak out, I don't think I need something quite that expensive....

 

I've done this job by using a couple of jacks. I used a bottle jack to support the transmission and used a small floor jack under the spring mount to lower the spring. Not too difficult, but always be careful with compressed springs.