Here we go with another long list:

I am now getting several problems that are starting to mount up, it's getting a bit worrying. If I may, I will list them all just in case some might be related?

1st: I have felt for some time the car is under-powered, much more noticeable when cold!! From a standing start (when warm) there seems plenty of power, goes through the gears but in 3rd/4th/5th I can feel a definite holding back, feels like the car wants to just go but something is stopping it? Foot down to accelerate and it kicks down a gear or two, engine roars away, and we get there .. but only eventually. Throttle body dirty perhaps? I do have a 'right bank knock sensor' fault?

2nd. Sometimes it 'sticks' in 3rd gear and wont change up, when this happens, there are a couple of options. Switch to Sport mode and it changes up. Switch Sport mode back off, after it's changed gears, and it continues to work fine? Using the 'J' gate also causes it to change OK after it sticks? Both 'J' gate and Sport mode options work great cold or warm. The transmission filter is new, and fluid level is OK.
Just today, when using the 'J' gate in traffic, the lever wouldn't stay in 2, it kept jumping out into 3. It eventually stayed in 2 after I held it there for a while?
Maybe significant or not, but sticking in gear only happens when it's cold, the power problem is always there, but significantly worse when cold! Could the transmission problem and power problem, when cold, be linked? Not sure how/if the transmission can cause a lack of power, or if it's just coincidence?

3rd: And probably most worrying. When applying the brakes the car is pulling to the right, and if applied hard (when I eventually get some speed up) I get a 'throbbing', a repetitive thump-thump-thump noise felt through the car (sorry if that isn't clear but it's the only way I can describe the noise!). I did fit new discs all round, new pads and all suspension joints, bearings etc as said in previous posts, and it has run great for months? I suspect the pulling to the right is the nearside (RHD) caliper not working as it should, seems logical and I need to check that out first, but it's the thump-thump that worries me?

4th and last for now: Between 50 & 70 mph it feels like there's a massive 'blebb' in one of the tyres, or a prop shaft joint that's gone bad, as, the car rumbles along. Putting the transmission into Neutral doesn't stop or change the rumbling, it's there no matter what I do?

The main reason for putting everything into one post here is that I've had all sorts of suggestions, such as "front sub frame mountings going mate", "everything's moving at the front when you brake". And/or "front shockers gone" (as those were the only things I didn't change when doing a refurb of the front end - they seemed fine at the time). I've also had the suggestion that the wheel balance is off or buckled wheel.

So I hoped putting all the issues down at once might reveal something obvious? Or account for 1 or more of the problems, but not all them? Maybe they're just totally separate issues all together and I've been unlucky, I don't know?

Gone September 2016, the car was 18 years old, so I've spent loads of time and effort making sure the underside, steering & suspension, all timing chains & tensioners, etc etc, were all renewed or at least in good condition... you guys know the required drill with these cars better than me?

After the dreaded bore wash fix recently, the car starts first key every time now and has run great, until the above started all within a week! So I need to fix it all, and you guys out there have helped so much to date I thought it would help to put the whole picture down in one post? There are no DTC's except the right-hand knock sensor fault, and sometimes doesn't help .

As always, grateful for all suggestions...

 

The knock sensor being bad wont help, as this pulls timming out of the engine ( retards the timming ) to protect the engine.

This could well be the lack of performance.

The pulling to the offside could be nearside caliper not working, but could also be a distorted/cracked offside disc.
It could also be a bent wheel, distorted tyre ( I have had a few tyres do this ) or a wheel bearing going bad.

 

+1 andrew. You should probably check the transmission fluid level, a pain, I know.

The thumping under hard braking may just be the abs preventing wheel lock.

 

Paul,

Sorry to see that since we discussed the transmission matter privately, things seem to have worsened.

I have since read a ton of internet forum posts of mainly BMW members, having problems with their ZF's.
Non so far is the same as you, but in several cases, more or less identical issues were related to one of the several sensors fitted in the box.

My advise remains the same, visit a good and specialized garage who does German brands, and have the gearbox codes read as a starter.
I am by far a specialist in gearboxes, but common sense says that if indeed a sensor malfunctions, it should leave some kind of code.
If they have experience with the ZF 5HP24, they should be able to locate the problem.

On the braking problem, I do agree it sounds wheel / rim / brake related.
If it is the front, you should clearly feel it in your steering wheel, if not, then it is probably the rear.
I guess jacking her up, checking the wheel bearings, then remove a wheel will find the culprit (bearing, tire, rim, warped disk, pads, ...).

Good luck!

 

Hi RJ237. I regularly check the transmission fluid level as I have a very slow leak in one of the cooler pipes, I'm just fortunate to have a son with a four poster. As EricJansen has pointed out the same as you, when I press the brake on hard I'm not talking 'full on' as such, more of a mini emergency stop. Yes Eric, I do feel it through the steering wheel. I also read that having a bad Knock Sensor, besides retarding the timing, could also cause problems with transmissions as it affects the balance of everything in the ECU, if true this could answer some questions. I've ordered 2 new Knock Sensors today (just hope the 'screw in' ones I've ordered are what mine uses, and not the 'bolt on' type). Fit those, check the front offside for disc warp, bearings etc, and also check the nearside caliper. I hope doing this will help eliminate some of the problems. Keep the ideas coming please..

 

You got me confused then, as I thought you had the 2 knock sensors replaced after the bore wash episode.
Surely first thing to do is to get rid of any codes.

But remember, your OBD2 reader does not read transmission codes, that's why I advised a specialist as a next step.
I hope I am wrong, but to me the power & shift problems as you describe sound gearbox related, not engine related ..

 

Hi Eric. No I didn't replace the Knock Sensors after the bore wash issues, the engine seemed to run fine, there were no warning lights such as limp mode, or reduced engine performance warnings... nothing! I only know about Knock Sensor fault using the Torque app 'faults option' on my phone.

Yes I agree, seems there's a transmission fault, but replacing the Knock Sensors will eliminate the power problems hopefully, then I will be better placed to deal with the gearbox issues. One by one as the saying goes!

 

After reading up on the Forum, and a few tips, I decided on Friday that to change the Knock Sensors, it would be much easier to remove the Inlet Manifold. I realised that this meant also removing the TB and TB Elbow too, but as I intended a thorough clean out of these it made sense to have the TB on the bench. So I went to the local Jag dealer and ordered the inlet manifold seals, and the TB Elbow seal.

Removed the manifold no problem, and I took the advice of ericjansen and checked the vac pipe and water pipes in the ‘V’ channel, everything was ok. I also took the opportunity to change the thermostat upright housing as I couldn’t get at the back 2 bolts previously, so this was an added bonus as well. The TB and Elbow were removed, TB left on the bench. Then I changed the Knock Sensors being very careful to torque them correctly. Fitted all the new seals and refitted the Inlet Manifold with the Elbow in place with its new seal.

Again, I took the advice of ericjansen and was very careful with the TB, making sure I cleaned out as much as possible, especially around the butterfly and spindle. Fitted a new gasket and refitted the TB. Yet again, following advice, I cleaned out the MAF as much as I could, though I couldn’t see if it was clean or not, I could only spray some Card Cleaner into it. Is there a way to dismantle the MAF for cleaning?

After all was back together I did the hard reset and fired it up, started first time off the key, and I have to say the car has never had so much power all the time I have owned it…WOW!. With reference to my original post, I’m not sure how significant this might be, but after trying the car out on a run, and even twice when cold, all the gears are changing perfectly … so far anyway?

So it seems for now things are a lot better, though I need to find out more about this rumbling that happens between 50 & 70 mph, again mentioned in the original post. I have noticed that, at say 60 mph, putting the car into Neutral doesn’t stop the rumbling, it’s still there, so it doesn’t appear to be ‘running gear’ that’s amiss? Could it be a faulty wheel bearing front or rear, if it is, it may answer the slight pulling and vibration through the steering wheel on heavy breaking?

Thanks to all so far, with all the help and advice, I feel I am getting towards having a generally sound example of this marvelous car, and the vast amount of my fixes are due to the fantastic people on this amazing site!

 

Have you checked the wheel bearings when the car is in the air? Spinning each wheel, checking for play, etc. I've got a similar noise on my car, very low frequency hum between 50 and 70. Have you checked the output shaft bearings for play? Jack up rear of car, push in and out at 12 oclock on each wheel and feel for play. If there is play, have someone push the wheel in and out trhere while you're underneath the car and watch the diff output flange for play.

I've got replacement output shaft bearings that are hopefully good, I'll be installing them at the end of the week if other small parts come in by then. I'm hoping that will fix it, and I don't need to do wheel bearings as well. See here https://www.jaguarforums.com/forum/x...stions-176097/

 

Hi nilanium, and many thanks for your reply, I had intended posting you as I read you had a 'similar' noise on your car. I have checked all four wheel bearings for play yes, the rear are all new including every bush, spacer, and universal joint on the whole back end. I changed the same bushes, joints etc on the front too, but not the wheel bearings, I just didn't have the tools. The only things I didn't change on the back were the output shaft bearings (basically cos I didn't know these were a common problem when I had the whole lot out of the car). I have checked for play at the back too, but only felt movement in one bottom hub pinion, so removed and replaced both sides with new shafts, bearings, and spacers there as well.

To date, I have suspected the prop-shaft couplings, and/or the universal joint in the centre of the shaft, it certainly feels similar to a prop-shaft problem I had years ago on a Mk III Ford Cortina! But, it is a much lower frequency noise, I put that down to the quality of car build and dampening etc?

I do know the problem was there before I started any work on the back and front, it seems slightly worse now than before, maybe the new joints etc have accented the original problem? Think a replacement diff from the local breakers would tell me more!

 

First, grease the zerk fittings on both sides of the differential. Then check for tire balance.

 

I also have a new noise which I've been able to identify/replicate recently, a sort of metal knocking when off-throttle coasting between about 20-35 mph. I'm hoping it's those same output shaft bearings but I'm not too sure. It's definitely drivetrain related, going into neutral doesn't change it. I'm suspecting something propshaft related there as well, so maybe that could be the cause of the hum as well. Spinning the rear wheels by hand in the air didn't reveal anything useful about that noise...

I'll upload a video and some more details on my thread, hopefully later today. Really, I won't know for sure until I've redone those output shaft bearings, then I'll have a chance to crawl around and check propshaft for play/roughness and look more in depth at the diff.

 

Just a few questions:

nilanium: How difficult did you find it to change the Output Shaft bearings? Looking up and reading I guess it's a lot easier than removing the back-end to change the Diff? I'm also intrigued to know if this is a common problem, the bearings in my Diff could have been in there 18+ years?

Anyone else had similar problems with low frequency/vibrations and found these bearings to be the culprits? The only bits that aren't new on the suspension and drive of my car have been checked and they seem fine. This problem was there before I did all the suspension and drive work, I hoped with everything I did it would resolve the problem, but no!

 

I haven't installed them yet. Removal was somewhat tricky but not unreasonable. Getting the half shaft nuts was annoying because the u joints get in the way of properly seating an appropriate socket on there. The circlips may fight you as well. It required a 3ft prybar and donkey kicks to free the pass side output shaft. Apparently doing output shafts is doable in situ. I'm doing subframe for other things anyway, will do that in the next couple days.

On that note, I'm replacing the whole output shaft-bearing assembly with ones from the junkyard. To R&I fresh output bearings would involve a press and a replacement collar and bearing (and probably a circlip too). Not too much extra work at that point, but it does involve a press.

To replace the diff you will need to drop the rear subframe, still need to unbolt half shafts, and basically disassemble the entire rear subframe to free the diff from its cage.

 

Hi nilanium, thanks for the info. Yes I know about the rear assembly, I had the whole thing out, completely stripped down when I replaced all the joints, bushes, and bearings. Here's mine when I had it out on the workbench..


I had it all eventually pulled apart, cleaned, and painted up ... some of it powder coated ... why oh why didn't I know then about the problematic output shaft bearings then??
Anyway, I do remember that it wasn't 'too' much to get the unit out, biggest problem was getting it from the car into the garage and on to the bench, it was such a heavy dead-weight.

It seems my best way forward is to make sure these bearings are the problem, if so, change in situ. I am using my step-son's 4 poster lift at the weekend, I know he has a dial tool too ... let's see what I find.

Another thing that totally confused me at the time--the very bottom centre of the picture, the small spacer rings that fit on the top of the 'A' frame bush -- only two are used -- why are they sold in the UK in packs of 5? How weird is that?

 

I ran into the same issue when servicing the fuel injectors on our '93. For some unexplainable reason, Jaguar sold the clips that hold the fuel injectors in the proper orientation in boxes of 5. Very weird for a company that up to that point in time was famous for its 6- and 12-cylinder engines....

Cheers,

Don