Knocking

Hi. I had a “new” gearbox fitted to my TD5 a couple of weeks ago. It was very stiff to start but the last couple of days it has bedded in and gotten much better. This week, when driving, I noticed a new noise. Thought it sounded like a rocker out of adjustment or something like that. It was going to go back to garage next week anyway so pretty much ignored it. Going to work this morning, I noticed it was louder. On the way home, it sounds like a hammer has been welded to the side of a prop shaft. Gets faster with speed but not louder (don’t think it can get any louder anyway). Put your foot on the clutch to coast and it goes away. Can’t drive it now as it feels like something is goi g to go bang. Nothing obvious under the car (a nut missing off a gearbox mount but replacing it did not fix it). Supposed to be driving from Dorset to Northumberland on Friday and affriar to drive it 100m now). Will go back to garage again next week but any ideas? The rear prop feels tight I. The hand but the front on has some play. Always looked after the vehicle but the gearbox had been a pain from the very beginning (had a replacement which failed and so (under warranty), now on the third one. No off-roading and so not abusing it! Cheers. Gar

Worth removing each prop in turn and driving in diff lock. Start with the front, noise goes away its something at that end.

The rear prop can feel tight even when the joints are worn because it may be under tension as a result of the handbrake. If you release the handbrake and rock it back and forth a bit to loosen everything up (obviously not in a place where it's going to roll away) then the slack shows up.

It's also worth jacking it up and rotating the wheels by hand and seeing if anything's rough or loose in the hubs or axles. I had a slight noise a couple of years ago that turned out to be the bolts holding the brake disc onto the hub being a little loose, despite having been installed to the recommended torque with Loc-Tite. Mind you, they'd lasted over seven years and were around due for replacement anyway.

You might try running it in gear with both propshafts disconnected to see if that makes a difference. When I put a reconditioned box on mine I did this as soon as I had the transfer box on and the clutch pipework reconnected, so I could check I could find all the gears and there wasn't any untoward noise or vibration. Fortunately all was well in my case, and enough torque was being transmitted to make the soles of my wellies smoke when applied to the spinning brake drum (don't copy Uncle Brown at home boys and girls).

Brown said:

The rear prop can feel tight even when the joints are worn because it may be under tension as a result of the handbrake. If you release the handbrake and rock it back and forth a bit to loosen everything up (obviously not in a place where it's going to roll away) then the slack shows up.

It's also worth jacking it up and rotating the wheels by hand and seeing if anything's rough or loose in the hubs or axles. I had a slight noise a couple of years ago that turned out to be the bolts holding the brake disc onto the hub being a little loose, despite having been installed to the recommended torque with Loc-Tite. Mind you, they'd lasted over seven years and were around due for replacement anyway.

You might try running it in gear with both propshafts disconnected to see if that makes a difference. When I put a reconditioned box on mine I did this as soon as I had the transfer box on and the clutch pipework reconnected, so I could check I could find all the gears and there wasn't any untoward noise or vibration. Fortunately all was well in my case, and enough torque was being transmitted to make the soles of my wellies smoke when applied to the spinning brake drum (don't copy Uncle Brown at home boys and girls).

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Thanks for the info Brown. Managed to get the car to the garage today (just). Just had a call and the transfer box has eaten itself (big bits of metal coming out of it)."New" transfer box required! Just looking into options now. Is this something that goes and if so why? I have always had the car serviced. The oil in the transfer box is clean. Could the old dodgy gearbox have caused a problem? I have not been offroad...and the only time I have tried the diff-lock it has been tricky to get it engaged/disengaged. Bit fed up now. Had the car almost 3 years. Spent about £4k on stuff (gearbox, propshaft, clutch cylinders, servicing, doors, wiring etc) and it seems that it it has not made a difference to the reliability or the ongoing bills. Car has done about 125k (01 Plate). I suspect it was owned by a quarry previously (given the silty mud jammed in the chassis), but it does not look like an abused one (or I would not have bought it).

I suppose you could look at it as an opportunity to replace with a Disco transfer box which has higher ratios
Few extra mpg and a bit quieter
Bit coincidental for it to go straight after the gearbox work, I guess it's just a bad run of luck

CastawayRobinson said:

Thanks for the info Brown. Managed to get the car to the garage today (just). Just had a call and the transfer box has eaten itself (big bits of metal coming out of it)."New" transfer box required! Just looking into options now. Is this something that goes and if so why? I have always had the car serviced. The oil in the transfer box is clean. Could the old dodgy gearbox have caused a problem? I have not been offroad...and the only time I have tried the diff-lock it has been tricky to get it engaged/disengaged. Bit fed up now. Had the car almost 3 years. Spent about £4k on stuff (gearbox, propshaft, clutch cylinders, servicing, doors, wiring etc) and it seems that it it has not made a difference to the reliability or the ongoing bills. Car has done about 125k (01 Plate). I suspect it was owned by a quarry previously (given the silty mud jammed in the chassis), but it does not look like an abused one (or I would not have bought it).

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Well, they're quite long lived units in my experience. Hence the large number of secondhand transfer boxes knocking around on Ebay, long after the remainder of the vehicle has rusted away. But they go wrong occasionally. Personally, if mine wears out or the gears start shedding teeth I'd look at a gear set from Ashcroft https://ashcroft-transmissions.co.uk/product-category/lt230-ratio-changes/ As you can see they're available in a variety of ratios as well as the standard ones. However, if you're getting a garage to do it the labour costs would be quite high. So it might be better to go for a reconditioned unit or good secondhand one. I try and do as much of my own work as possible, but in a vehicle that's twenty years old you'd expect to get through a few hundred pounds worth of parts each year. On the plus side, there's very little depreciation on these, and TD5 models appear to be changing hands for a lot more than I spent on mine in 2012, so they're worth hanging on to.