Wierd rear booming noise
- Thread starter smartone
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2.0_hippo
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classictransporter
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Hi
Mine is now a high mileage RR (225k miles). Bremble is right with the torque converter, I had the same issue most evident at 38 and 55mph. The only other similar noise which I have encountered during that mileage, is a seized bearing in UJ on the rear propshaft - vibrated when under load until ripped its mounting rubber. To be fair to the RR, mine has had a 3.5t trailer on the back for the last 100k. Anyone know a good source for rear propshafts, mine needs doing again?
Mine is now a high mileage RR (225k miles). Bremble is right with the torque converter, I had the same issue most evident at 38 and 55mph. The only other similar noise which I have encountered during that mileage, is a seized bearing in UJ on the rear propshaft - vibrated when under load until ripped its mounting rubber. To be fair to the RR, mine has had a 3.5t trailer on the back for the last 100k. Anyone know a good source for rear propshafts, mine needs doing again?
2.0_hippo
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Blimey
225k
These engines do go well
225k
These engines do go well
Grit Valve
2000 4.6 Vouge
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:hysterically_laughi:hysterically_laughi Missed that one - well spotted !!Love it
smartone
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For me, this seems to have completely gone....but I did notice that it was only noticeable when the petrol tank was fairly full.....because I run LPG from its own tank, I don't carry much petrol usually.
Maybe coincidence but it didn't come back and I haven't spent a bean on it but I keep the petrol on 25% full most of the time.
Maybe coincidence but it didn't come back and I haven't spent a bean on it but I keep the petrol on 25% full most of the time.
roadnutter
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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.
On the BMW 4.4 V8's with the ZF 5HP24, 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 / wear with the torque convertor...I would put this as the last thing to try.
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. 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
On the BMW 4.4 V8's with the ZF 5HP24, 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 / wear with the torque convertor...I would put this as the last thing to try.
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. 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
