Gearbox "rebuild" concern...looking for advice
Discussion
Guys
Just spent nearly £400 having a gearbox rebuilt. Putting all other factors aside for a moment, post rebuild, if I'd filled it with fresh ATF, driven no more than 20 miles, and dropped the ATF into a clean drip tray and it looks like this, should I be concerned? The plastic thing is the gearbox oil filter, and on the picture of the tray, all of those flecks are pieces of aluminium.
Gearbox is an LT77 out of a Defender. Looking for an unbiased view, and hopefully from someone qualified/with expertise.
Thanks in advance,
Just spent nearly £400 having a gearbox rebuilt. Putting all other factors aside for a moment, post rebuild, if I'd filled it with fresh ATF, driven no more than 20 miles, and dropped the ATF into a clean drip tray and it looks like this, should I be concerned? The plastic thing is the gearbox oil filter, and on the picture of the tray, all of those flecks are pieces of aluminium.
Gearbox is an LT77 out of a Defender. Looking for an unbiased view, and hopefully from someone qualified/with expertise.
Thanks in advance,
Thanks for the reply.
Essentially, I did a service on the vehicle (fairly new to me but drove fine beforehand) and changed the ATF in the (manual) box. As soon as I did this, I started getting a high pitched whining/grinding noise when giving it a bootful. The noise was not connected with engine revs (it won't do it in neutral, and it won't do it if I gently bring the revs up to the redline when driving). It only does it when giving it hard throttle in gear. A theory is that the clean ATF flushed out some crap and there's a bearing spinning in the case under high torque conditions. The old stuff was a bit goopy too.
Anyway, I had the gearbox rebuilt, put it back in and I have identical symptoms. At the same time, I also installed a different transfer box, so I have ruled that out. Ditto complete clutch kit and spigot bearing. Diff oils changed too, nothing nasty was found in the old (and very clean) oil.
When they rebuilt it, the gearbox rebuilders changed some baulk rings and other bits but apparently didn't find anything hugely wrong with the box. At the moment, they are saying the grinding noise must be something else on the vehicle and their gearbox rebuild is perfectly sound but I doubt it very much. At the end of the day regardless of any other faults anywhere else on the vehicle that may, or may not, exist, I just cannot believe that a freshly rebuilt gearbox producing that amount of aluminium swarf in less than 20 miles of driving is normal. I think they've simply just missed whatever was causing the original issue but don't want to admit it. I'm not a rocket scientist but a horrible grinding noise that only happens in gear under load, accompanied by that much aluminium swarf kinda points fairly squarely at a gearbox problem...
Essentially, I did a service on the vehicle (fairly new to me but drove fine beforehand) and changed the ATF in the (manual) box. As soon as I did this, I started getting a high pitched whining/grinding noise when giving it a bootful. The noise was not connected with engine revs (it won't do it in neutral, and it won't do it if I gently bring the revs up to the redline when driving). It only does it when giving it hard throttle in gear. A theory is that the clean ATF flushed out some crap and there's a bearing spinning in the case under high torque conditions. The old stuff was a bit goopy too.
Anyway, I had the gearbox rebuilt, put it back in and I have identical symptoms. At the same time, I also installed a different transfer box, so I have ruled that out. Ditto complete clutch kit and spigot bearing. Diff oils changed too, nothing nasty was found in the old (and very clean) oil.
When they rebuilt it, the gearbox rebuilders changed some baulk rings and other bits but apparently didn't find anything hugely wrong with the box. At the moment, they are saying the grinding noise must be something else on the vehicle and their gearbox rebuild is perfectly sound but I doubt it very much. At the end of the day regardless of any other faults anywhere else on the vehicle that may, or may not, exist, I just cannot believe that a freshly rebuilt gearbox producing that amount of aluminium swarf in less than 20 miles of driving is normal. I think they've simply just missed whatever was causing the original issue but don't want to admit it. I'm not a rocket scientist but a horrible grinding noise that only happens in gear under load, accompanied by that much aluminium swarf kinda points fairly squarely at a gearbox problem...
Hard-Drive said:
I'm not a rocket scientist but a horrible grinding noise that only happens in gear under load, accompanied by that much aluminium swarf kinda points fairly squarely at a gearbox problem...
It doesnt really.Even more so with a rebuilt box. And you dont mention whether there was swarf in the filter pre-oil change, or after it was rebuilt...
And it sounds like this is 4wd...so could be front diff, rear diff, propshaft related, transfer box, some sort of engine/trans mount etc etc.
And does this noise happen in 1 gear, or all gears ?
Swarf was there pre rebuild, and post rebuild. The pics are of fresh ATF that was dropped from the box, post rebuild, after a mere 15 miles of driving from installing post rebuild.
I find it very unlikely it's the transfer box as I put another, different one in at the same time and it would be very unlikely that they both have an identical issue. Props tend to rumble when they are worn, not scream/grind. Obviously I took the props off when I removed the gearbox and they are fine on both splines and UJs. I also don't believe it's the diffs, as there would be debris in the old oil.
It does it in all gears in low range, and 1,2,3 in high range.
I find it very unlikely it's the transfer box as I put another, different one in at the same time and it would be very unlikely that they both have an identical issue. Props tend to rumble when they are worn, not scream/grind. Obviously I took the props off when I removed the gearbox and they are fine on both splines and UJs. I also don't believe it's the diffs, as there would be debris in the old oil.
It does it in all gears in low range, and 1,2,3 in high range.
That much swarf after 15-20 miles coupled with noise under load is not right.
Either they didn't clean the gearbox before re-assembly which is pretty sloppy or they've forgotton to put something back in the 'box.
The noise under load suggests either a spacer of some description or a thrust bearing is missing and you have rotating steel internals on aluminium casing.
I take it you have the correct grade of oil in the gearbox?
Either they didn't clean the gearbox before re-assembly which is pretty sloppy or they've forgotton to put something back in the 'box.
The noise under load suggests either a spacer of some description or a thrust bearing is missing and you have rotating steel internals on aluminium casing.
I take it you have the correct grade of oil in the gearbox?
Iain this is an LtT77 manual box I presume ? I know with the 2WD LT77 boxes they have an internal oil pump but you need the correct grade of oil for this to work correctly are you sure they run on atf . If that swarf is from pre rebuild they have not done the job correctly if it was cleaned properly it looks like it is grinding itself to bits
Ian
Ian
OK I think I've found the main issue.
The vehicle (still pretty new to me) is a bit of a bitsa, and the air cleaner arrangement is far from satisfactory, with some crap clearances. Daft as this sounds, when the engine is under load and the turbo comes on boost, the intake hose is deforming and moving a small part of the air cleaner assembly into contact with the alternator fan. Which explains why it only does it when the engine is under load/on boost, and doesn't do it in neutral just revving with no load. I removed the offending bit of air cleaner, went out for a drive and did not get my mystery noise, no matter how much I provoked it. Had tell-tale rub marks on the air cleaner housing too. So I guess it never needed a box rebuild all along (although in fairness it was a worn 30 year old box originally designed for a non-turbo engine so it can't have hurt to have it done)
That said, it still seems like a lot of metal. The rebuilders say this isn't excessive for that kind of box, so perhaps some "running in" miles and a very early fluid seems sensible, and then I'll monitor it from there. I'm definitely using the right grade...ATF Dexron III in a Land Rover LT77 box.
The vehicle (still pretty new to me) is a bit of a bitsa, and the air cleaner arrangement is far from satisfactory, with some crap clearances. Daft as this sounds, when the engine is under load and the turbo comes on boost, the intake hose is deforming and moving a small part of the air cleaner assembly into contact with the alternator fan. Which explains why it only does it when the engine is under load/on boost, and doesn't do it in neutral just revving with no load. I removed the offending bit of air cleaner, went out for a drive and did not get my mystery noise, no matter how much I provoked it. Had tell-tale rub marks on the air cleaner housing too. So I guess it never needed a box rebuild all along (although in fairness it was a worn 30 year old box originally designed for a non-turbo engine so it can't have hurt to have it done)
That said, it still seems like a lot of metal. The rebuilders say this isn't excessive for that kind of box, so perhaps some "running in" miles and a very early fluid seems sensible, and then I'll monitor it from there. I'm definitely using the right grade...ATF Dexron III in a Land Rover LT77 box.
If the debris there now is the same as was coming out before I can see how that could have happened. To take every single component from a 'box apart and clean it thoroughly would take hours and hours, possibly a whole day so it's likely it will have been left as you probably wouldn't have wanted the bill for that. Whilst it doesn't look great, tiny particles of ali won't harm anything.
If it wasn't for the noise I would change the oil a few times to flush it and see what happens, but if the noise is genuinely from the box then of course you need to think again.
You could either carry on changing the oil for new or filter/let settle and decant what you've taken out and put it back in and see how it goes. Personally I think I would give that a go as it's an easy option, tranny noises on a 4wd are a nightmare to track down sometimes as they travel up and down the various connected components.
If it wasn't for the noise I would change the oil a few times to flush it and see what happens, but if the noise is genuinely from the box then of course you need to think again.
You could either carry on changing the oil for new or filter/let settle and decant what you've taken out and put it back in and see how it goes. Personally I think I would give that a go as it's an easy option, tranny noises on a 4wd are a nightmare to track down sometimes as they travel up and down the various connected components.
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