As reported in my IRS Rebuild thread, after eliminating the noise created by the leaking the differential, I was able to hear a different noise while driving. In an attempt to find what that might be, I lifted the car and was re-checking if there was any play in the wheel bearings, re-checked the pinion, etc. and seeing what I could discover while the car was off the ground. I couldn't find anything with play or obvious source of the noise.

However, while turning the rear wheel by hand I heard a distinct ticking sound. It took a bit of gymnastics, but while under the car and using my foot to turn the wheel I was able to isolate the noise as coming from around the rear of the transmission. Attached is a video I took by placing my iPhone on the creeper under the location of the sound. You can hear it change as I change the speed of turning the wheel.

Any ideas what that sound might be? If it sounds like that with my simply turning the wheel by hand, what would it sound like driving?

Thanks

 

U-joint. Didn't listen to the vid clip due to slow internet, though.

Doug

 

Strange indeed.

All I can think of in that area that rotates is the Prop Shaft, and the trans Output Shaft.

Uni Joint would be my best guess also.

 

@Grant Francis so let me guess, to get that U-Joint, I've got to undo the Rube Goldberg transmission mount?

 

Its been a long time since i was under an XJS turning a wrench, but IIRC, you undo the flange mount to the differential, drop down the driveshaft and just pull the driveshaft assembly out.

But, i may be mistaken, I've been working on mostly American cars for the past 45 years.

If I am mistaken, it would be good time to modify that trans mount to make it less Rube Goldberg.

Doug

 

You are now a MASTER Jaguar Tech, spot on young man.

It may be a GM trans, and GM had a sliding yoke at the trans, CHEAP way out.
Jaguar went the Engineers way, and has a flange, retained with a nut, with a mating flange as part of the propshaft, and the sliding splines also part of the shaft.

Some claim, hahaha, that the 4 bolts are accessible without messing with that mount, I doubt it.

That mount is not that bad, see the attachment. Main thing is to jack the trans up into the tunnel as far as it will safely go, the prop it with a stand/blocks of wood. WATCH THE FAN BLADES PLEASE. I run Efans, so dont bother with that step.
This jacking releases a lot of the punch of that spring, but it still packs a punch. Threaded rod, and slowly release the thing is the easiest and safest.

About 4 beers from memory.

 

The mounts do have to come off to get to the flange bolts at the gearbox end. Sadly

 

Well at least I learned Greg's safe and sane method for removing the trans mount when I replaced it a few years ago, though I didn't think I'd be revisiting that any time soon. I'll have fun trying to locate the threaded rods I used.

Is it odd for that U-joint to go out? Seems from searching the archives that the half-shaft U-joints are more likely. Maybe it's because it's hidden and is less likely to get greased?

Thanks

 

Greasing, maybe.
I have seen some with nipples, some not.

I detest this "sealed for life" rubbish. What is this "life"?????

Hidden as it is, greasing is a pain I suppose, but doable. Then again, how many mechanics?? even have a grease gun these days, and if so, how to use it correctly??

It is a rare item to fail in my years, only had one, and that was the S Type a good many years ago.

 

"Life" is the warranty period plus 1 day (not kidding), and it's kind of rubbish that the manufacturers aren't more honest about that.

Both my X350 and Range Rover have the same "sealed for life" transmission, and if you waited until 100K to do a fluid change it would be a regretful decision (but you know that). No drain plug, and you have to replace the plastic pan and all the torx screws because the filter is built into the pan. Like I said, warranty + 1 day, and they don't even think about DIY.

 

Agreed.

Your threaded rods are on your bench, just to the left of all those empty beers bottles.

Ya need to do a beer run before that joint work starts.

Have fun mate.

 

Since I'm going to have undo the trans mount to access the front prop-shaft u-joint, should I upgrade the two rubber bits CAC3227 and CBC2517 to polyurethane while I have it out?

I know in most places (except the steering rack) poly isn't always an upgrade, but wondered if in this case it might be. When I replaced the spring and rubber bits about 5 years ago, the rubber parts were completely AWOL with only a few remnants left.

 

Poly was an issue in suspension components because of squeaking.

I doubt your trans mount will squeak. It is generally firmer, but i don't think it would transmit excess vibration.

Doug

 

I use Poly for the "cotton reel" and rubber for the spring seat, never had issues.

 

I put poly into the transmission mount, but removed it, as on my car at least, it made a noticeable increase in vibration.

 

Tomorrow I'm going to be attempting to tackle taking out the prop shaft and replacing the u-joints.

I was reviewing the ROM and thought it wouldn't be so bad other than the trans mount, but I've already come across a potential issue. The ROM says there is a flange at the downpipe, and with the one at the other end near the over-axle pipe it would be easy to drop the middle sections of the exhaust.



But that is not what I have, with the two catalytic converters mine looks like this:




So I assume I unbolt the flange near the IRS cage, and loosen one of the clamps at the other end. My concern is that I couldn't get the resonators apart from the over-axle pipes, so how do I get the pipes to separate at the clamps in the front? Is there a trick to getting pipes separated at that type of clamp junction? I'm concerned that between corrosion and exhaust sealant it's going to be basically glued together. I also noticed a pinhole right at the intermediate clamp and I'm worried I'll damage that area taking it apart.

Suggestions? Helpful hints?

Thanks

 

Trick?

Well, in my experience based on other cars, you will end up beating the snot out of it with a hammer, then use a Sawzall to cut the pipes, and end up replacing the pipes.

They do have wide band clamps for use in rejoining cut pipes, as long as the cut section is straight for couple inches on each side of the cut.

I greatly dislike exhaust systems.

YMMV.

Doug

 

Not much progress in getting to the prop shaft, or at least as intended. I've determined that the intermediate pipe sections of the exhaust need to be replaced, and at least one would not have survived removal in good enough condition to reinstall. Where the pin hole was located turned into a larger one with just a touch, and it's clear on the other side it's about to open up as well, so I'll wait until I have the replacements on hand to tackle the prop shaft. I might do the front silencer delete as well while I'm at it.

Though the noise is no longer a mystery, the condition of the intermediate pipes is (at least to me). Every other section of the exhaust looks in amazing condition for a 33 year old car -- California car for it's entire life and having never seen snow/salt. However, the intermediate section is quite rusted and looks completely different than the rest of the system, almost like it was made from a different material. It's the factory installed system as there has never been any exhaust work performed or required.

So what gives? Is there something about that section that causes it fail before anything else? Only thing I could think of is that it's the lowest point in the system and condensation collects there, and it fails from the inside out...? But the hole is next to the union, and the silencer side of the union looks great. Just seems odd.

 

The front section (downpipes and catalyst) are made from Inconel steel on some cars. I de-catted a USA imported 1983 for a friend and the part was made of it, or something very like it, I am pretty sure. The steel was PERFECT, had a coppery sheen to it, and was incredibly hard to cut - which was the only way I could get it off.

If you do de-cat it, I highly recommend Bell Stainless from SNG. I have had such a system for over 20 years and still 100%.

 

Thanks that explains it, the cats are like that with a coppery or bronze like sheen, the silencers too.

Unfortunately, I can't de-cat it. In California, cars have to be '75 model year or older to be except from smog testing. I was only thinking about eliminating the silencers in front of the cage. My understanding from reading numerous threads is that with dual cats still in place, there isn't much difference in sound with the front silencers removed, but it eliminates the most restrictive section of the system.