That's the torque converter lock-up clutch failing. The 5HP24 transmission doesn't have a torsional vibration damper in the LUC, it has a continuous slip mode instead (approx. 3% slip) - activated between around 25mph and 56mph - which is designed to eliminate the transmission of torsional vibrations from the engine through the driveline. When the LUC begins to fail you feel & hear the vibration.

The most obvious point to spot it is at around 30mph in 4th gear (around 1300rpm) on a slight incline and light throttle in 'D'.

A re-manufactured torque converter costs around £225 and takes 5 hours to replace
These are exactly the symptoms I have on my recently purchased L322 (2002) luckily it is still under warranty from the dealers. I notice that you mentioned Kmotors in Leyland which is just around the corner from me, would you recommend?
 
I have very little personal experience of using K Motors but I haven’t heard any bad things about them. They used to re-manufacture their own transmissions but I don’t think they do any more. I know their parts division (LRDirect) is the main part of the business now, but the garage has been going for donkey's years.

The ‘captive clutch’ torque converter design of the 5HP24 means that the retaining plate for the LUC piston is accurately friction-welded into position during manufacture. The weld has to be machined off to release it and subsequently re-welded accurately back into position again once the friction plate has been replaced. This is a specialist job so I would want to know who was supplying the re-manufactured unit if I were you.

TC%20LUC%20diagram_zpsuqy866sa.jpg


LUCdrivinghub.jpg


LUCPiston1.jpg


Frictionplateinsitu.jpg


K Motors used to fit new torque converters rather than re-manufactured ones, but there’s a big difference in the price. Do you not have to return to vehicle to the dealer that you bought it from if it’s a warranty job?

Phil
 
Hi, thanks for the quick reply; yes I do have to take the vehicle back to the dealers (well they are coming to pick it up and take it to their garage). My main concern is getting the diagnostic correct and I thought that if the dealer does try to wheedle out of the warranty I would have somewhere to go to back me up with your diagnosis. Your explanation was bang on so I know for a fact that that is the cause. Is it wise to drive knowing the LUC is failing?
 
It’s just worn. The total movement of the LUC piston from fully on to fully off is only around 1 mm so it doesn’t take much wear in the friction plate for the problem to start. I drove mine for several thousand miles in this condition and when I eventually replaced it the friction plate looked like this :

Frictionplateclose.jpg


You just don’t want to leave it so long that it looks like this :

ghurLUCfrictionplate2_zps3bfa21ff.jpg


So I wouldn’t panic, just take your time and get it fixed properly and make sure that the re-manufactured unit comes from a reputable source like JPAT, Sussex Auto Parts or Mackies. Just as important to make sure that they only use Mobil ATF LT 71141 fluid when they refill your transmission after the TC replacement. The fluid is expensive so they might try to use a cheaper alternative – the problem being that there isn’t one.

Four%20Fluids_zpsqg4wxpz0.jpg


Phil.
 
Can we presume there are four contenders, given your last pic, and the fact that ZF make the box?:confused:
When the transmission was launched back in 1996 the only fluid authorised for the 5HP24 was Esso LT 71141. Exxon-Mobil subsequently re-branded this fluid as Mobil ATF LT 71141.

Rebadged71141.jpg


ZF then decided it made commercial sense to start selling fluids badged under their own name so they got Pentosin in Germany to start producing a fully-synthetic version of LT 71141 which ZF sell as ZF Lifeguard Fluid 5.

Pentosin%20MSDS_zps1d6z6iev.jpg


ZF’s SDM also lists Pentosin ATF 1 as the correct fluid for the 5HP24, which sort of implies that Lifeguard Fluid 5 and ATF 1 are one and the same fluid.

Pentosin%20ATF1_zpseufmgxka.jpg


Here in the UK, semi-synthetic Mobil ATF LT 71141 is by far the easiest and cheaper of the three fluids to get hold of.

Phil
 
Thx for that.

I believe Pentosin make all/most of the available oils and sell it wholesale to be branded accordingly, (Comma etc) maybe not initially but from a business view money and sales volume talks.
I may be being naive but if the specs match it will do the job, even if it's branded "Tesco economy".

Not trying to create an OIL THREAD, god forbid.
 
Back to the intermittent rumble strip sound that is emitted; I've noticed another noise of that description, it seems to be coming from the rear of the car (passenger side) could this be a worn bearing as well as the failing LUC, making in total two rumble strip sounds?
 
Ah he's just being a clever dicky then. And no, not breaking the law when overtaking as long at you return to the speed limit as soon as it is safe to do so. And didn't know it was a gearbox issue until checking the forums.
That's true in Spain where you can exceed the 120 kph up to 140 kph to overtake a slower vehicle. Try that defence in this country ;):D
 
Back to the intermittent rumble strip sound that is emitted; I've noticed another noise of that description, it seems to be coming from the rear of the car (passenger side) could this be a worn bearing as well as the failing LUC, making in total two rumble strip sounds?
If you put the vehicle in manual or sport to take the TC out of the equation and then drive around various bends and see if you get the rumble noise when cornering then i would say wheel bearing is suspect as well. i think i am right in saying if you turn at reasonable speed to the right then the left bearing will be noisy and vice versa
 
So the car went back to the dealers who (surprise), couldn't find the faults I described. I sent an email asking them to repair or give me a full refund as it was still under warranty. The car was returned to me the next day as they stated they had fixed the problems. After driving the car it was apparent the problems had not been fixed. I called them and asked exactly what they had done and they said they had changed a solenoid seal to fix the oil leak (which has not fixed the problem - it still leaks). Asked about the failing TC they said they could not reproduce the symptoms and had therefore done nothing else to the car. Oh and they said they don't do refunds which is rubbish because of the Consumer Rights Act 2015 makes it an implied term of the contract "As you are in breach of contract and and I've owned the product for less than 30 (by law now 60) days I am within my statutory rights to ask for a full refund of the original cost paid". It looks like the small claims court for me, (another problem I could do without). Watch this space! I have booked the car into K Motors for a full service and diagnostic session.
 
So the car went back to the dealers who (surprise), couldn't find the faults I described. I sent an email asking them to repair or give me a full refund as it was still under warranty. The car was returned to me the next day as they stated they had fixed the problems. After driving the car it was apparent the problems had not been fixed. I called them and asked exactly what they had done and they said they had changed a solenoid seal to fix the oil leak (which has not fixed the problem - it still leaks). Asked about the failing TC they said they could not reproduce the symptoms and had therefore done nothing else to the car. Oh and they said they don't do refunds which is rubbish because of the Consumer Rights Act 2015 makes it an implied term of the contract "As you are in breach of contract and and I've owned the product for less than 30 (by law now 60) days I am within my statutory rights to ask for a full refund of the original cost paid". It looks like the small claims court for me, (another problem I could do without). Watch this space! I have booked the car into K Motors for a full service and diagnostic session.
Why are you spending money on it if it could be going back?
 
Good question. I need to know exactly what is wrong with it because they won't tell me.
It's been back and they obviously don't want anything to do with it or me. I've had a rethink and I'll be taking legal advice on the matter. There are a number of companies that offer post sale inspections for used cars whose reports do stand up in court so I'll use one of those instead of having the service. Looks like I have been sold a pup but the last laugh will be on them, I take exception to being done over.
 
Good question. I need to know exactly what is wrong with it because they won't tell me.
It's been back and they obviously don't want anything to do with it or me. I've had a rethink and I'll be taking legal advice on the matter. There are a number of companies that offer post sale inspections for used cars whose reports do stand up in court so I'll use one of those instead of having the service. Looks like I have been sold a pup but the last laugh will be on them, I take exception to being done over.
I like a man who bears a grudge.:D don't get mad get even;)
 

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