Broken Diff?

[Redsteve]

Hello guys,

first of all, may I wish you all a very Merry Christmas and a Happy New Year.

While I was driving home from work yesterday I could hear a very feint knocking sound coming from the back of my LS (MK4 2000). It was only present while I was accelerating, as soon as I took my foot off the throttle the knocking stopped.

Within about 5 or 6 miles the knocking got considerably louder, still only when accelerating though.

By the time I got home (another couple of miles) I could feel the knocking coming through the car, still only when on the power. I tried putting the car into reverse and still it was knocking.

The noise seems to in time with every wheel rotation, under hard acceleration the knocking is loud, under less acceleration the noise is less loud but the frequency relates to the wheel speed, while the car is coasting there is no knocking.

The noise seems to be coming from around the diff area, do you think my diff is beginning to expire?

The car has done 170,000 miles and has not been given a hard life, I am quite a steady driver, just the odd squirt every now and again.

I have done a couple of searches on the forum and I can't find anyone having a similar problem, hopefully someone might have an idea what the problem might be.

Thanks.

Steve.

[Malc]

I don't know but I'll start the ball rolling and suggest it might be a very worn bush somewhere and nothing tooooooo dramatic.

Malc

[ROYT]

Usually diffs start to whine on drive or overun when worn, and if lacking oil will get

noisier and noisier before failing.

If you have a steady knock I would look at the driveshafts first before the diff.

[steve2006]

Also have a look at the prop shaft,I think there is a rubber coupling in there somewhere that can wear out.

Just had a look on Toyodiy and there are indeed rubber couplings at both ends of the propshaft,I have seen these on eBay but the part no. is 37511-30020.

Check the UJ also

[sparkystav]

I had a knocking on mine, took me ages to find.

in the end it was the magnetic plug from the diff drain plug had come loose and was rattling around the diff,

[Redsteve]

Well guys,

firstly, thanks for all your input.

I had a word with the local garage this morning and the owner told me to drop the car in this afternoon and he would have a quick look at it.

He took it for a quick trip up the road and then put it on the ramp to have a squint underneath.

It looks as though the nearside driveshaft is the culprit for the knocking noise. As he twisted the prop there was a couple of mm of play on the n/s driveshaft but none on the o/s one.

I have got a few prices for a rebuilt driveshaft, they seem to be about £200 inc VAT and delivery, the mechanic said it would take a couple of hours to change.

I am hoping that the shaft will last until the new year as there is no chance of getting the old one off the car, sent away, rebuilt, sent back and refitted before Christmas.

I am praying to the Lexus Gods to look after my car until January, if all you guys could keep your fingers crossed for me too I would be very grateful.

Once again, thanks for your replies.

Steve.

[Thunderchild]

Hi Steve,

Firstly let me say how unlucky you are to have that happen at this time of year and secondly that in my opinion you are taking a major risk running the car with the driveshaft in that state. There is a chance that the CV joint could disintegrate completely and the damage that the shaft whirling around can do is not something you want. If you can, leave her off the road until you get the replacement part or drive very, very carefully.

HTH

Tc

[Monster-Mat]

check the nut on the end of the driveshaft (wheel end) i had one very slightly loose, on my GS, and the result was the diff was making some terrible noises, once tightened, it was quiet as a mouse..........................this was after i bought another diff to swap in

[Redsteve]

Hello again chaps.

I have decided to follow Thunderchild's advice and lay the old girl up until the new year.

I drove to work this morning (about 10 miles) very carefully and smoothly with no knocking to be heard but coming home this afternoon was a different story.

The knocking has started happening on very light acceleration now and there is a constant rubbing/rumbling sound now coming from the rear nearside wheel area.

I am very lucky, a friend of mine has a Range Rover which is only a second car which he has let me borrow until I can get my Lexus fixed. It is a V8 so I will still be making regular trips to the petrol station, in fact thinking about it, I will be making more trips to the petrol station! :o

I plan to get the car onto some ramps over the next few days and have a good root around underneath to make sure it is the driveshaft which is causing all the grief.

Once again, thanks for all your thoughts, I will keep you posted as to what happens.

Steve.

[Monster-Mat]

Hello again chaps.

I have decided to follow Thunderchild's advice and lay the old girl up until the new year.

I drove to work this morning (about 10 miles) very carefully and smoothly with no knocking to be heard but coming home this afternoon was a different story.

The knocking has started happening on very light acceleration now and there is a constant rubbing/rumbling sound now coming from the rear nearside wheel area.

I am very lucky, a friend of mine has a Range Rover which is only a second car which he has let me borrow until I can get my Lexus fixed. It is a V8 so I will still be making regular trips to the petrol station, in fact thinking about it, I will be making more trips to the petrol station! :o

I plan to get the car onto some ramps over the next few days and have a good root around underneath to make sure it is the driveshaft which is causing all the grief.

Once again, thanks for all your thoughts, I will keep you posted as to what happens.

Steve.

steve see my last post above yours, exact same symptoms, .....

[Redsteve]

steve see my last post above yours, exact same symptoms, .....

I will be checking the prop shaft but I have seen with my own eyes the amount of play in the n/s driveshaft so it will need to be changed even if it is not the main culprit for the horrible noises coming from under my car.

I will not be able to get under the car until Tuesday to have a proper look but I will keep you all posted.

Merry Christmas to you all.

Steve.

[toxo]

Hopefully you've got this all sorted by now, I know how unnerving it is driving around with a broken rear driveshaft!! If you are still after any parts however, I have a complete rear transmission from a Y2K LS400 sat around in my workshop. It's non DHP but that shouldn't make much difference as far as I'm aware.

[Redsteve]

Hello guys,

sorry I haven't updated this thread like I said I would but I have had a few internet connection issues, I am currently trying out a dongle for quicker speeds as I have been stuck on dial-up.

Anyway, back on topic, I got my car back this afternoon all fixed and running like a dream.

In the end I had to get a new driveshaft as the old one was sent away and couldn't be repaired (not sure why).

The new shaft cost about £290 which isn't too bad when you consider to re-con the old one was going to be about £220 inc delivery and Lexus quoted about £650.

I have been driving round in my mate's V8 Range Rover for the last few weeks and I can report that I get over twice as many MPG out of the Lexus, the Rangie was doing about 10 MPG!

I am so glad to have the car back, it sounds daft, but the thing I have missed the most is the auto dipping rear view mirror. All the other gadgets on the Lexus are nice but you can easily do without but when you can't dip the mirror then driving at night is a pain.

Thanks once again for all the input.

Steve.