Unfortunately, the transmission in my '87 is no longer functional. It failed suddenly thankfully close to home - heard an odd something breaking sound when I was leaving a stop sign and it started slipping badly. Now it only moves forward a bit when its cold making "mechanical" noises doing so. Once things warm up, it will not move forward at all. Oddly fluid level was /is good and looks and smells ok.

Anyway, my question - do I need to concern myself with the year of the car as the source for a replacement transmission - other than its the TH400 and making sure the transmission has the speedometer sender?

I am debating myself between attempting to rebuild the current transmission vs finding another one. I have a great workspace - other than needing to cart things down into the basement

 

If the TH400 is from another XJS V12, then it will be the same as yours.
Most decent transmission places can rebuild a TH400 with no bother, it can be done by you too, but there are one or two crucial clearances that must be dead on. As to the actual swapping of the tranny, this thread may help you, if you have not done it before:
https://www.jaguarforums.com/forum/x...ox-xjs-221677/

 

Thank you Greg! And also for the link to your amazing thread on this subject.
I'll be finding your posts about the steering oscillations the new transmission cured. I've got bad steering shakes at around 30MPH and around 50. I planned on suspension work before the transmission problem occurred - which I'm still going to do but very good to know there's another possible cause that I'll be solving

 

In my case, after lost of fruitless effort resulting frommy ignorance (!), it turned out to be the differential failing. If your wheels are correctly balanced, then the diff is the most likely cause.

 

As a transmission tech I have a couple of questions. Is reverse still ok? Has the transmission ever been serviced?

 

I may be wrong, but while the guts of the tranny are the same, I don't think that a tranny from a GM car would bolt up.

 

Correct, it has to be an XJS or Jaguar XJS Series III V12 saloon gearbox casing.

 

Hi Tyee,
It will go in reverse. As for service history, I don't know but I'd say I doubt anything has been done in a long time other than me checking fluid level.

I wasn't as diligent a buyer as I could/should have been, I bought this car back in the spring. Unfortunately for me, I really like the look of the XJS-C so I bought based on body condition. The car is complete and no rust but I am sure it sat for a long time.

 

 

Well done! and snap!

 

If you decide to rebuild the transmission yourself, let me know. TH400 is not a difficult one to do and would be glad to offer any help I can.

 

A good shop should be able to do the job for between $2000-$2500. Engine removal not required.

If the car is new to you then this is not a bad price to fix things. Excellent time to replace all fuel line and EFI hoses; refurbish the EFIs (the baskets are undoubtedly toast, new seals and test for spray pattern would be good. This is KEY: Service your Lucas distributor, make sure the centrifugal advance works easily, lubricate the center shaft, new vacuum advance is probably needed (Get the GM part). New 8mm wires. New fluids: oil, P/S, Coolant, brake. Get all grease points well lubricated. Replace front shocks, U/L ball joints. Check all calipers for functionality.

If you don't repack the front wheel bearings make sure to lubricate the hub generously. Same for rear hubs thru the access round portals. Ample fresh grease in there. New Diff fluid can't hurt.
Getting this all done in one effort will save time, money, and headache down the line.

 

Greg you look much younger than you let on…

 

My goal is this weekend is to get the transmission separated from the engine. I am leaning towards paying for a rebuild - I have never done any transmission work (but then again, I've never done any of the work I've done thus far and no experience didn't stop me).

I have a good area to work, my fear is that I miss some critical detail - it is a lot of work to find that out!

Beyond transmission - plan is to remove front crossmember and renew the suspension and brakes 100% (car had terrible shake, poor steering quality) - I can visually see deterioration on various bushings. I'll be doing rear brakes and evaluating the rear suspension also (that's a whole other topic!). But beyond bushings perhaps replace shocks since they are of unknown age - white Gaz-Adjust with red logo?

I'm in full on "might as well" mode...

 

Since you are doing brakes be sure to replace the brake line hoses.

Also a very good time to replace the rubber fuel line hoses that up and over the rear cage on both the supply and return lines.

I know the list of things to do always seems to grow but since you are already into a space best to address these items before they become issues, like when driving down the road and you get a split in one of those hoses and start leaking gas or your brakes fail due to a split hose.

 

FWIW I think having the tranny professionally rebuilt is a very sensible plan. There are critical clearances in it which if not correct spell disaster...

New shocks for sure, but to retain the famous Jaguar ride, you need either OEM shocks (which were Boge part number Boge 30-D86-A009 and are still available if you look) eg:
https://www.simplyperformance.com/sh...boge-shocks-68

or adjustable ones (as you mention, I do not know that particular make) as long as they have a wide range of adjustment. The best ones over here, which are widely used by the Jaguar classic fraternity, are Gaz adjustables eg:
https://www.ebay.co.uk/itm/123226089...Bk9SR_qxtK_iZg

Absolutely the right decision to change all the suspension rubbers, including engine mounts, front crossmember mounts, rear cage mounts, control arm and rear radius arm bushes. However, be warned, you absolutely MUST use genuine OEM Metalastik brand items, front and rear in ALL places. These are getting hard to find, but Jack Weston at David Manners
https://jagspares.co.uk/
is the guy to talk to as he still has some, I think. If not, get the part numbers from Jaguar Classic and start searching!
https://parts.jaguarlandroverclassic.../brand/jaguar/
trawl ebay etc etc. Anything else will fail in weeks or months, as these sad photos illustrate (I learned the hard way) these innner front lower wishbone bushes from a well known aftermarket supplier, had been on the car two months:

 

Further to Greg's great advice, note that there are 2 types of Gaz adjustable rear dampers for the XJS. The basic model has a fixed height for the spring seating. Which is fine if you can absolutely guarantee that your springs are perfect and have NO variance. And that you will always be able to buy perfectly configured new springs (you won't be able to!)

The other option that Gaz sell is an adjustable height spring seat variant, which enables you to perfectly set the ride height irrespective of any variances in your springs. I fitted the basic type with my new Eibach DB7 springs, but the car rode a touch low. So I replaced them with the adjustable height ones, and now I have a perfect ride height.

Good luck

Paul

 

Wow Greg that is terrifying and is causing me serious pause...
Alas I am in the US so sourcing from the UK is a serious budget hit, but also I cannot afford what you showed happening!
I live within can go in person distance from a "major US Jaguar parts supplier" - past transactions have gone well - but I've not bought anything this critical.
What I've read here and elsewhere has steered me (pun intended) well away from polyurethane except for specific uses like steering rack bushings. But is this an option I should even be considering from a longevity trade off?

And also 100% on the fuel and brake hoses! I'd already done all of the engine related fuel hoses and they were in terrifying shape. I am in full on "hey ...you should do this now while you can do it easily" mode

 

I do not think that shipping from the UK will be exhorbitant. (you USA guys are paranoid about that!). The problem is that if you want to keep and enjoy the car, and experience its astonishing combination of ride and handling, not to mention this state actually lasting for years of use, you honestly have no choice but to source Metalastik bushes. If necessary, wait and save would be my suggestion, that's what I do. This is far more important than buying expensive shocks, as shocks can be easily replaced later. Getting the foundations right is key.
This is the Manners price on their website for the real thing:
https://jagspares.co.uk/lower-wishbo...-s2-s3-c8673-2

About 20 USD each; but you may well get a club discount, etc. Talk to Jack.

Not letting a council of perfection be a problem for you, there may be some bushes on the car which are still in OK shape. Post some pics of the ones that are on any given assembly you are working onto see if they can be left.

 

There are different approaches and philosophies about these things. Throughout the entire car hobby poor quality parts (and high prices!) have forced us into being more selective about what parts we buy.....or even what we chose to replace versus leave as-is. The "while I'm at it" approach, which I'm very familiar with, can become problematic if/when you unknowingly install lower grade parts.

As the decades have rolled by my own attitude has gradually changed. IMO, there's a case to be made that still-serviceable parts be left alone. Personally, I wouldn't assume that every rubber part must be replaced.

I recently bought yet another oldie Jag, an '87 XJ6. Thirty eight years old but only 69k miles. The only parts that actually needed replacing were the ball joint boots and the rack bushings. And that's all I did. There was a time when I would've just done a full suspension overhaul "while I'm at it". But that was when high quality parts were a lot easier to source and a lot less expensive.

Another example is my 2005 S-Type. It now has 44k miles. There was a time when I would've replaced all the cooling hoses as a routine matter. They're twenty years old! I've decided against it. For the time being, at least. Why? Because the originals are still in amazingly good shape and I have very low confidence in the quality of replacement parts. I might well be taking a step backwards.

It's a quandary. And I'm not saying that choices that are right for me will be right for you.

Anyhow......

Poly bushings. They're generally unpopular because they tend to be noisy and and....you guessed it....some vendors sell low grade junk and others sell high grade stuff. Are you really sure about what you're getting?

IMO, the one area that you really need to be careful is the lower control arm bushings. Why? Because they're so labor intensive to replace if you install low grade parts. I would definitely spend the money for the true, genuine Metalastic replacements. If you make a bad or unlucky choice elsewhere....upper bushings, ball joints, tie rod ends....it isn't quite so bloody hateful if you have re-do the job sooner than expected.

All of the above is just my two cents

Cheers
DD