Hi Chaps.

Around 5 Months ago i was experiencing a grumbling / droning noise under light acceleration (seemed to be in 4th). Took it to a transmission specialist and diagnosed as Torque Converter.

Refitted Re-Man torque converter from J-Pat and seemed to cure the problem, although a couple of weeks later it seemed to do the noise now and again. Ignored it to see if it got worse as it was barely noticeable to the untrained ear.

3 Months down the line and it seems to have got quite a lot worse. worse on inclines when under load and seems to be in 4th gear a loud drone and the revs jump up and down a little when this sound is happening.

Im stuck really to see what it might be. My transmission guy does a lot of these range rovers etc and says he does get some failure rate on the re-con units. Anyone have any ideas / advise?

Thanks.

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I know this is an old post but I thougth I'd add some ideas based on my experience. Hopefully this can help others.

Generally the drone is the torque convertor slipping more than its meant to be in its semi lock (30 - 55mph) and total lockup (55mph+) mode. When it starts the drone will be under load from 30 - 55 then it will start to slip over 55mph a bit then it will start to get worse with noticable rpm changes when the noise is present. The torque convertor problems are noticible first but generally the other friction plates in the gearbox will be affected also.

This can be caused by;
!.) Using the wrong fluid which has the wrong amount of friction additives (anything other than Esso LT 71141 is wrong for this gearbox!). Other fluids that claim to be LT71141 generally are not correct for this gearbox.
2.) Contamination of the gearbox fluid. Most likely water from a failed gearbox cooler allowing coolant in. Can also be caused by the vent hoses sucking in water if they are incorrectly located. If you drain a bit of gearbox fluid out and its slightly milky...its water in the fluid. Basically the water changes the friction / viscosity of the fluid and causes it to boil as well. It will kill the whole gearbox very quickly.
3.) Low gearbox fluid level...you will also get other noises from the gearbox, particularly when cold and on a hill.
4.) Mechanical problems with the torque convertor...I would put this as the least likely.

If you have water...then you need to get all the fluid changed immediately a few times. For anything else I suggest you add between 2 and 4 tubes of Dr Tranny Instant Shudder fix, or equivalent. Its basically a concentrated shot of friction additives for gearbox fluid. Basically gearbox fluid is a base oil with friction additives so this is just fixing the oil that you have already. It cannot do any harm and its only £35 for 4 tubes on eBay or equivalent. To get it into the box is the same as the normally filling procedure, flat surface, raise to highest suspension level so you can get under the car, engine running, gearbox about 30 - 40 degrees, then remove filler and squirt in. I used a syringe and a bit of thin pipe but you can get it in with the Dr Tranny container if you are careful.

The result will generally be silence almost immediately. If you add 4 tubes or equivalent and it doesn't sort it, then it maybe the torque convertor. In that case it will cost over £500 for labour, recon convertor and fluids.

I was given the wrong info when I first had these problems and it cost me a lot of money. None of the gearbox experts I spoke to at the time told me to add friction modifiers to my fluid to sort it. Do not leave it as it will wear out the torque convertor plates eventually, but that is the affect and not the cause!

Hope this helps someone.

James

I was having a similar noice coming from sounded like rear wheels, so thought my bearings had gone, left it for a few weeks and then noticed some oil on Christmas Eve coming from the middle of the car, had a look under and oil was spread around transfer box, so took to the local indy when they opened after Christmas, eventually they found that the input shaft bearing had collapsed and that had caused the leak and noise. Car eventually fix and collected on Thurday and bearing noice gone and car running smooth after a new transfer box fitted, so your issue could be in a similar area of rear diff and transfer box.

I am no expert on the ZF gearbox, but I seem to remember that they can suffer from shuddering at around the 75k mark, and that power flushing the gearbox is the way to cure this. Cam Tech Craig or RRPhil (gearbox guru) should be able to tell you more. When my GM 5L40E box when tits up, there was shuddering at 30 - 52 and then it would all settle down and behave it's self again, classic sign that the torque converter is about to pop it's clogs. I could make it stop by either, making it kick down or by knocking it into sport mode, like manual but but only move the gear lever to the left not up and down. If your gearbox is slipping above 55 then I suspect that all the clutches are worn out, and it needs a rebuild. Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Hi there. Just bought my Range Rover yesterday after 35 years ago as 18 year old boy being in awe of it's ride and presence when I got to ride in one. I drovetit from Sussex north to Glasgow (400 miles) and although it has done 180000 miles had been well looked after (2004 4.4 V. From the word go I had the same judder/noise/rev changes between 30-55 MPH. I need to reconnect the LPG system which I am doing today and would also like help to find the best way forward to cure this as I don't want to do any damage. It would also be good to be armed with a bit of knowledge before entering the garage so I don't get the wool pulled over my eyes, pay lots of cash and still have a problem.