a kick in the rear

skyway · July 22, 2017

Good evening guys,

I wonder if anyone could shed some light on my situation regarding my ls430.

She has developed a banging? maybe a Thud might be a better way to explain it, when it goes into gear this can be on my drive way or on the motorway when I take my foot of the accelerator pedal she thuds kinda forward and then from the back when I or the cruise control starts accelerating again I remember having something like this a long time ago on a bike but that was a rubber bushing in the wheel...... of course its not going to relate to this i'm just rambling on, any help on this would be most helpful as I love my car and I don't want to get rid of it anytime you know before I die.

many thanks John

thatfatbloke · July 22, 2017

I had something similar to this on one of my old W124 estates a while ago. Turned out to be a worn gearbox mounting.

Colin M · July 22, 2017

Another possibility might be wear and play in the universal joints on the prop shaft. Put the car on some ramps and twist the prop shaft backwards and forwards to see if there is any play or movement. If there is, this might show up as a clunk or thud on acceleration or deceleration.

skyway · July 22, 2017

Thanks guys, that sounds about right to me.

I will buy all the mounts engine, trans hmm i think I remember buying that rubber joint for the propshaft some time ago but never fitted it,

I guess now's a good time.

Thanks again for your help

skyway · July 23, 2017

I have checked the engine bay out... when I change gear the engine rocks and ,..... thuds.

Engine mounts it is.

:)

Colin M · July 23, 2017

Pleased to hear that you have managed to track down the cause, Allan - hopefully not too expensive to fix.

Newbie1 · July 25, 2017

Be interested to know what the quote is for changing your engine mounts. I've just had the gearbox mount done which was the easy part...if the engine mounts are anything like the Soarer V8 then it is a bugger of a job.

skyway · July 25, 2017

Me to Phil, in the interest of preserving my sanity I will be doing the job myself come hell or high water.

Newbie1 · July 27, 2017

Just inspected the transmission mount I had changed. At 71,000 miles the transmission mount that came off was in perfect condition. No damage or tears to the rubber. The only thing was slight compression from original specs but still pretty good going.

skyway · August 12, 2017

ok so update time..... I hope you guys are having a good weekend.

I (with help) have changed the engine and gear box mounts... no easy feat with an lpg kit stuck on the engine we had to drop the subframe as loads of pipes were in the way top side which stopped us raising the engine also we had to take off the steering rack and a load of other bits.

Anyways after 2 days of maximum effort it was complete.

I drove it away only to hear a clunk and feel a kick in the bum (also felt a little rage I think I may have driven it into a tree to teach it a lesson But i think it may have hurt a bit)

So back to the drawing board, now thinking rear diff/ mount or gearbox.

anyone got any ideas which dont involve fire... im having those already :)

is200 Newbie · August 12, 2017

Drive shaft guibo worn? (Big rubber disc mounted between transmission and shaft)

skyway · August 12, 2017

it looked good today.... but i do have a spare I will change it out

thanks worth a try at the mo

runsgrateasanut · August 13, 2017

Wildcard - Is your lpg tank (toroidal?) properly secured? Obviously not if it happens when stationary.

skyway · August 13, 2017

Hi yeah it's struck down well.

I'm gonna get under it today and check the prop shaft I'm hoping there is some play and I need a new diff I think that's easier to fix than a gear box

ambermarine · August 13, 2017

Allan

Check out all the suspension bushes on the rear with a close look at the trailing arm bushes on the body fastening if you can wiggle the arm at all the bush is very worn, the fastenings are under compression at all times so they will look tight even if worn.

I had this issue on my Mark 1 Ls400 and it turned out to be the trailing arm bushing both sides completely shot in the end but by that time I was getting vibration at certain speeds.

The clunk sound was identical to your description.

The suspension on the LS430 is updated but the components are similar

skyway · August 13, 2017

oooooooo damn Phil I do hope you are right IM gonna jack the car up now and have a look see

Colin M · August 13, 2017

Like Phil, I had a clunk from one trailing arm bush so definitely worth checking them. I don't think Lexus do the bushes separately. I bought a new trailing arm from Amayama in Japan which worked out quite a bit cheaper than buying a new one from Lexus, even after paying postage and customs expenses.

skyway · August 13, 2017

What do you think?

Movement in all the rubber

Suspension is off it's rubber mount

Colin M · August 13, 2017

If there is movement in all the rubber, I would replace the trailing arm as a first step before doing anything else. This may well cure the problem. I would check both trailing arms - the other one may have similar wear, although not necessarily, as only one arm needed replacing on my 1996 car and the other one was (and still is) fine.

ambermarine · August 13, 2017

Allan

Looking at that pic I would say your problem is identified.

We changed the bushing back then with a tool we made to extract the old bushing and inserted a new bushing bought in the USA

It is now more economical to buy the complete trailing arm with new bushings on both ends as after market suppliers are now supplying at reasonable prices.

skyway · August 13, 2017

The trailing arms are hard to come by on eBay.....I am hoping I dont have to go to the dealershipoff.

All I could find is these http://www.ebay.co.uk/itm/LEXUS-LS-430-control-arms-rear-4-3VVTI-2001-/401356614336?hash=item5d72b7eac0:g:nRQAAOSwpdpVWcFe

and http://www.ebay.co.uk/itm/Hardrace-Rear-Toe-Control-Arms-Pillow-Ball-for-Lexus-LS430-UCF30-/322545452823?hash=item4b19350717:g:usQAAOSwI2dXFfGA

Thanks for your help guys.

ambermarine · August 14, 2017

Allan

There is no point in putting second hand units on, they will be worn and the problem may get worse.

Google the Japanese car spares sites .

Newbie1 · August 14, 2017

Agreed. It's suspension so get new items in there. It hurts, especially when you spend £500 on suspension on a £1000 car (my story recently.) But, running these cars always involves digging deep at some point in the interests of safety and preserving the wonderful attributes of Mr Toyota's best.