This is a follow on the Broken Down Again topic.

Having changed a few items I am slowly getting the cause. Well eliminating!

When rolling/moving there is a dull thud that seems to come from around the drivers footwell. The faster you go the more frequent the noise. It is not intermittent and starts at less then 5mph.

I have now changed the front and rear propshaft union joints, and replaced the Front Diff.

Tomorrow I will jack up the rear of the car, (Front Propshaft is off) and run the car, hopefully I will not hear any noises. That would mean the fault is on the front axle so would guessing it will be the hubs.

Chris has also suggested to place the fuse in the top right position on the drivers seat fuse box, and roll the car down the hill, this ensures the car is in neutral.

Does anyone have any other ideas?

Sticking that fuse in would put the transfer box in neutral, which would rule out the gearbox but not the transfer case and propshafts.

Have you tried jacking up both wheels on the driver's side and giving them a bit of a spin to see what happens? You'll need both up because of the VC trying to lock the front and rear together, or you could drop the front propshaft - you should be good at this by now ;-)

gordonjcp wrote:

Sticking that fuse in would put the transfer box in neutral, which would rule out the gearbox but not the transfer case and propshafts.

Have you tried jacking up both wheels on the driver's side and giving them a bit of a spin to see what happens? You'll need both up because of the VC trying to lock the front and rear together, or you could drop the front propshaft - you should be good at this by now ;-)

Front Propshaft is still off to aid fault finding, I am sure the fault is in the front. Will jack up the back tomorrow and run it then can rule out the rear. Then jack up the front again and try turning each wheel with the prop still off. I have the flu at the moment and no garage means working on it is rather hard at the moment. Still will get there eventually.

Just make sure to chock the front wheels!

Of course, after nearly having an L322 fall off a jack once I am super careful. Learning a lot at the moment though.

OK, so got the back of the car in the air and ran the engine to get the rear wheels turning. The noise is still there so fault must be either transfer box, rear diff, rear hubs etc. I am uploading a video to youtube now (Slow Internet) of the fault, Breakers about 1 hour away have a full car in ready for stripping so will have to wait for parts until Tuesday at the earliest.

The Video... https://youtu.be/ZJB2H3n5d_0

Damn the breakers have a 4.0l V8 which has the 2pin rear diff, I need the 4 pin. Looks like a call to Ashcroft on Tuesday. Will stip it down tomorrow and Monday, expecting it to be harder then the front.

Rear is easier than the front. Hubs don't seem to rust in place as badly, probably cos they spend their lives very close to an oil bath
Be prepared for the ABS sensors to be well stuck in their housings though

No need to remove the ABS sensors, or even the brake calipers, to change a rear diff. Undo the 6 bolts that hold the hub in place, pull it out a couple of inches so it clears the diff splines and pull the diff. I've found that if you sit the wheels next to the hubs, you can rest them on those so they are not resting on the oil seals. Hardest part is getting the new diff into place, it's heavy and not the ideal shape to sit on a trolley jack.

What do people think, should i pop the front propshaft back on and drop the rear one off, jack the front up and run the car to see if its the transfer box?

Do you think its hub/diff related. Currently its still on stands at the back.

Put the front prop back on, take the rear one off and drive it. Don't forget to put a couple of nuts on the rear prop flange to stop the parking brake drum making a bid for freedom but that will tell you if it is in the axle or the transfer case. If you do change the transfer case, make sure you replace the gearbox output shaft oil seal as RAVE says. It's a real pain to have to take it off again just to replace that seal. A transfer box from a 4.0 litre would be a good one to go for, those from a 4.6 or a diesel will have had more torque through them so will be more likely to have a stretched chain.

Thanks would have forgotten the nuts on the transfer box when the rear prop is removed. Annoying as they were all new nuts on bolts on the rear prop! Might order several hundred when the online shops start posting again in the new year.

If I drive it though would the rear diff not be turning as a result of the rear wheels being dragged along? or am I being dumb? I am an Electronics engineer by trade, have an understanding of mechanicals.

On a side note I ordered all in stock items from LRDirect on the first working day after Christmas, paid next day delivery and its still not sent, I have cancelled it! V.Poor service for the second time. Island4x4 seem to be able to stock a bit more than them too.

I've only seen Britpart propshaft bolts being sold and as I would rather not have my props held on with something made from case hardened Plasticine, I've kept the originals and used a dob of Loctite on them. Not come loose in 140,000 miles.

With no rear prop the wheels will be turning but there will be no drive through the crown wheel and pinion so if it doesn't go away completely the noise will be dramatically reduced. As an electronics man you could do what I did and gaffer tape a mic insert to the diff casing and run that into something to record it. All you need do then is move the mic from one suspect component to the other.

Problem I found with LRDirect is that if you order a number of things and one isn't in stock, everything waits until they have the full order even if you do pay the extra. I've ordered stuff I've needed the following day but added a couple of extra bits onto the order only to find they weren't in stock so the stuff I really needed didn't arrive when I needed it. Their website does make this clear but who reads the small print? Although they are a bit more expensive than LRDirect, Island, etc, I've found Rimmer Bros to be the best if you need something really urgently.

Just an idea, Chris sent over his front diff to me, i fitted to the front but I have my old one here. Guessing its only a 2 pin, but as its a 4.6 V8 i know that it should be a 4pin unit on the rear. Could I fit this to the car for a few weeks to get it back on the road. Would save me a few quid hire cars etc.

I’d certainly stick it on, at least your mobile again and finally getting some use from the car

Well finally a day when the weather makes half a sense to go out. Went to start it and nothing. Flat battery! Typical as I don’t have a battery charger or a spare battery. So trip to Halfords for one. (It wouldn’t jump, I tried) so hopefully tomorrow with a charged battery I will make some progress.

Just quickly it’s a 70ah battery installed on this since I got it. Much smaller then the tray it sits in. Should it be higher capacity one?

Mine also had a fairly small looking battery, however when i checked the online lookup it matched what it was supposed to have (an "069", rated ~70AH iirc)

It wasnt that old, but had been flattened a few times and sounded weak when cranking, so i had a much larger "110" battery rated 80ah which was nearly new from a car i was breaking. It only just squeezes into the tray. Still sounds weak when cranking, must just be how it is.

Orangebean wrote this when i needed a new battery. I bought one and it's great.

Orangebean wrote:

Here you go....
http://www.batterymegastore.co.uk/hankook-mf31-1000.html
As fitted by a few on here. Physically about as big as you can fit in. More aH and CCA than those Halfords ones. Next day delivery to your door. 4 year warranty.

The manual does state a particularly small battery for the petrol models, which is a bit frustrating, as they were usually the ones with all the extras added on, that are more likely to be power hungry!

I only recommend either:
MF31-1000 from Battery Megastore (115Ah and 1000CCA)
Yuasa Type 664SHD (115Ah and 800CCA)

I also noticed on one of the P38's I looked at the other day, there was a Lucas LP31-1000 - again, same specs as the MF31-1000
I've also just found a 'Superbattery' SB31-1000 - which is rated at 130Ah/1000CCA which would probably be OK

All of the MF31/Yuasa, and Lucas batteries I've seen have the battery terminals in the correct orientation, and the batteries themselves just fit in the battery tray.

As a practicer of what I preach... I had one of the MF31 batteries in my P38, and it lasted 4 1/2 years (often being left 2/3/4 weeks at a time when I was away working) and it finally failed when I was away working for 8 weeks, and the RR wasn't started at all in that time). I replaced it with another MF31-1000 battery 18months ago, and that's still going strong!

Thanks guys,

Battery on removal was reading 4v!!! Fortunately seems to be taking charge and on last check was about 12v.

Will leave it on overnight and make do with this one until the car is running properly again.