Actually, yeah, that sounds better. The brake band can still be applied, but then nothing would turn, as the rear wheels are lock via brakes.

Being the pump would also mean that it does it in R and P as well. But the thread Starter only says D-2-1... If it was the pump ring gear, it would always do the sound, as the pump is always turning. Be it in P-R-N-D-2-1. The same goes for the torque convertor. It may well be, that it is the dreaded forward drum pressure plate, which does like to crack and snap...

I'll have a look in my TH400 manual at home... I know there have been problems with loose forward drum brake bands which can be slightly adjusted.

 

Great thanks guys. I spoke with an old guy here who seems to think that it might be an engine mount as the car has only 35k on it I've booked it into a local mechanic for Friday but would be good to give him your thoughts.

 

Hi guys, do I took the box out of the car and brought it to a guy who specializes in them..we took it apart and the box is in perfect condition. Like new..Except for slightly burned clutches and band on the second gear assembly.we are baffled as to what's going on..one theory is that the box was being driven low on fluid for a few years and prior to sale it was topped up.. TC also seems to be good..he's going to rebuild the box and hopefully we'll see from there!!

 

Burned clutches is not normal, could be that the clearances in the clutch pack were not correct. The rear mount is important to get correct too, make sure all the rubbers are renewed and up to spec.

 

Burnt clutches are never a good sign. Probably driven with not enough ATF.

 

So hi anyone who has contributed to this thread over the last months,here's an update.got the box reconditioned and the mechanic put it back in for me..the noise was still there😥! After lots of head scratching we decided to put in a new rear mount...problem solved 😗...I was really annoyed as I had asked him to check that day one so all the work was unnecessary on a 37k car...but to make matters worse I noticed it wasn't shifting well and when I checked the fluid turns out they didn't put enough in and now my new box has black fluid in it...got him to flush out the box hoping that no damage has been done as only drove 200 miles...got it back from him today and to my disbelief there's a scraping noise coming from the box now so obviously have damaged the clutch plates 😥 disaster...

 

222 - nothing I can add here but feel your pain, I would be very upset after all the effort and cost to be were your at.
Keep us updated as I am interested in how this turns out.

 

Wow, that's a nightmare. Given the full story, he should make it right without it costing you another dime, if he doesn't, I believe he's telling you all you need on whether you should let him touch the car again.

The unfortunate lesson here is if you are in a position where you have to pay someone else to work on the car, make certain that is someone who is really familiar with the XJS. An experienced XJS guy would have gone to the mount right away.

I'm really sorry, and feel your pain.

 

 

I found a transmission shop that I really like and have let them overhaul several transmissions for me. Good work, good people

But.....

They disappointed me a bit on my Jag.

I specifically told them to pay particular attention to the transmission mounting, owing to the fact the the V12 set-up is a bit weird.

When I got the car back the transmission operation was wonderful....but there was a vibration.

Made arrangements to return the car (140 mile round trip)

Long story short......they bollixed up installation of the transmission mount. Of course they fixed it at no charge and apologized all over the place. I'll gladly return to them but it's annoying when a shop (or any service provider) doesn't listen to the customer


Cheers
DD

 

Pretty darn sad state of affairs when a customer knows more than the service provider.
If dealers aren't interested in or know little about old school models and indie services that know these cars are few a far between, what's an owner to do? ..which brings us up to having to know everything about your own car.

 

I don't fault them for not knowing. How many 80s vintage, 12 cylinder Jags do they come across? Why would they know?

I blame them for not listening

Pretty much, yeah.

Cheers
DD

 

Hi there,
Thanks for all the contributions. Yes unfortunately I decided to sub out the work..I was too daunted by the xjs I do my own work on other stuff I have ..

I spoke with a mechanic who is familiar with the xjs an old family friend who has retired and we have both agreed that it's best if I bring the car back
to the company who rebuilt the box..they are familiar with the xjs.
I don't want the car to go near the original mechanic..
Hopefully they will have pity on me and not charge me an arm and a leg!!
I'll keep you posted.
Regards,
Scott

 

I'm curious as I have what sounds like a similar issue. I did the trans mount last summer but rumble/knock and whine didn’t go away. First gear on my XJS sounds like it has straight cut gears! When pulling away from a stop it almost always has a what I would describe as rumble and knocking. While driving given a little gas will make it rumble. Usually it can also be replicated in park or neutral around 2k rpm it starts knocking and can almost feel it. If I put it in D and do a slight brake boosting it will do the same. There is no whine in 2nd or 3rd. Trans has definitely been run to low on atf in the past. I’m just curious how replacing the trans mount stopped the trans from whining? I very well could’ve effed up install as the pieces were for sure not right when I took it apart. Another piece of the puzzle that I believe my trans is a used piece out of an old truck with straight cut first gear. Had a baby blue oil pan and a bright blue TC…A different forum member suggested TC might be the issue or the bolts to flywheel?

 

The first gear while is characteristic of the TH400, as well as the 4L80e. There have been several TSB out on it to not attempt to fix the noise, as it's operating as designed.

The TH400 in the Jaguar application has a unique case, so if you still have the V12 the transmission won't be from anything buy a Jaguar. With the paint job it has been out and possibly been rebuilt before, as from the factory the torque converter isn't painted.

 

yeah, I’m curious as to why it was taken out. I really feel like my best bet would be to replace the whole thing. I changed the fluid over summer and it had so much gunky dark residue and bits of what I imagine was clutch in it. There is a local junkyard with an ‘83 XJS that said I could have the trans for $200… For the noise and vibration put out I can’t believe how great it runs. No slip, just noise. Im feeling like it is the TC now because of how far forward it sounds/feels. It really ruins the Jaguar experience ha

 

If you do want to rebuild it, the internals are all standard GM parts, so they are easy to get. There are a number of videos out of that transmission, I like the disassembly ones from Precision Transmission on youtube. Richard gives lots of info on what to look for as he takes various transmissions apart.
Here is an example:

 

i was contemplating buying the junkyard unit and doing my first attempt at a rebuild… although nothing says it would need a rebuild.

 

You could certainly get the junkyard trans. Take the pan off, and look at the fluid, that will tell you a lot about the condition of the trans.

 

That’s guys vids and knowledge is great! I want to see him put one back together though. I’d feel better about doing it myself if there was a full build vid