Simon's new Xantia V6 and Leaf blog

[mickthemaverick]

Whilst looking at the Leaf videos I came across this simple, but I would suggest worthwhile, modification for Leaf owners which you may or may not know about!!

[NewcastleFalcon]

^^^^ Came across that with the Micra too...decent blob of red grease on the Micra and Leaf has been my adaption. Simon described it as a "strut top swimming pool" here
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The sound produced on the first video, after much to-ing and fro-ing with the NISSAN dealer, was one of the few resolved issues the chap had with his car, following renewal/repair of the driveshafts the awful noise went away.

"Upon inspection they (Glyn Hopkins Cambridge) noted that both the CV joints were worn so they replaced those used specialist grease and renewed rubber boots and the sound was gone."

The sound was similar enough to yours Simon, and according to "Fancy a BEV mate" replacement of the drive shafts corrected that sound....but not the click!

I'll not bog the thread down with more embedded vids...he mentions it in the first minute or so of this one...

https://www.youtube.com/watch?v=q_F0NzmxSmo

Regards Neil

[Mandrake]

Earlier I said I don't have the necessary service data for the Leaf for this job - this is incorrect, I had completely forgotten I'd downloaded a "copy" of the 2013+ Leaf service manual some time back.... link here:

https://drive.google.com/drive/folders/ ... sp=sharing

FWD.pdf is the main index which links to the other PDF's, TM.pdf covers reduction gear removal and disassembly.

I've only lightly skimmed it so far - I see I have a lot of reading ahead of me...

[Mandrake]

Ouch that sounds nasty Simon!

Sure we could get the box out of that if you want to have a go.... got to be easier than an ICE car, surely??

As far as I know the whole drive unit, as seen on the motor tear down video I posted earlier has to be lifted out the top of the engine bay before it can be disassembled.

So that means both hubs and driveshafts removed, coolant lines and HV cables disconnected then the full height stack lifted out over the front of the car onto a trolley to be wheeled into the garage - which would require a mobile engine stand with hoist. Not sure how heavy the whole lot would be - probably lighter than a combustion engine and gearbox but still not something you could lift without a stand.

One further complication I've thought of - the compressor for the heat pump is bolted to the side of the stack on the drivers side - not sure if it's attached to the motor or the inverter without checking, in any case I don't know if its possible to unbolt the compressor and leave it hanging connected to the A/C circuit, (it's quite small) or whether the A/C circuit would have to be disconnected requiring re-gassing afterwards. On an EV you have to use special non conductive oil in the oil/gas mix so many A/C regassing firms will not touch an EV so it could potentially be a trip to Nissan to re-gass the heat pump system if it did have to be disconnected.

Looks like a lot of work to me, but I'll have a read of the service instructions I just found to try to better gauge the work. £675 for labour starts to seem reasonable when you consider all the fiddly bits like dealing with possible heat pump system re-gassing afterwards...

I wonder if any normal transmission specialists would be able to rebuild the gearbox if it's not too bad inside - the issue might be whether parts like individual gears or bearings are generally available to 3rd parties to purchase - I have no idea if this would be the case or whether Nissan just considers the gearbox an indivisible unit.

[Mandrake]

Sounds familiar I've started the vid at the section where he recorded the sound. In comments on the second vid one person said NISSAN had authorised replacement of the driveshafts and the reduction gear.

I've actually seen that video already when I was looking for the driveshaft clicking noise but it's not until listening again that I agree that this is the same noise that I'm hearing, although his is a lot quieter than mine when you consider the microphone in his recording has been mounted under the bonnet close to the source of the noise.

Unfortunately it only serves to confirm the source of the noise as the gearbox.

[NewcastleFalcon]

Unfortunately it only serves to confirm the source of the noise as the gearbox.

You could maybe have a shot to nothing with the driveshafts, not in terms of getting a couple new ones at £400 each, but as part of the process, removing both, and giving them a decent dismantle and examination on "the bench" and pack them with grease, and refit the driveshafts. Probably a waste of fluid if you subsequently remove the box, but they don't take much, drain and refill the gearbox and see what sort of stuff comes out, metallic swarf etc.

Reason being, that "fancy an ev mate" chap George I think his name is, reported his noise as cured (eventually) by a driveshaft refurb and nothing else by Glyn Hopkin Nissan Main Dealer Cambridge.

REgards Neil

[mickthemaverick]

I have two more pearls to throw in the ring at this point:
1) I think there are two distinctly different faults involved in this discussion and the videos we have seen, firstly the click which occurs when the direction of force is altered, ie between accelerate and overun or stationary to forward or reverse motion and secondly the consistent rotational clicking that is apparently gearbox related.
2) The rate of clicking is definitely proportional to the rotational velocity of the system thus suggesting that in reverse there is a stationary object catching on a rotating one. The question is, is it a click per rev or 2 clicks per rev or how many clicks per rev? Does the number of clicks per rev relate to the number of teeth on a gear or maybe the handbrake cam wheel or is it some other source?

I haven't dismissed the possibility of those earthing brushes from my thinking which could be checked by removing their cover while the box is still insitu.

Finally Simon can you jack up both front wheels and then rotate them backwards by hand and see if you can reproduce the click in slow motion. If so can you count the number of clicks for one rev of the wheel which, with a little arithmetic, may give an indication to the actual source of the sound!!

[white exec]

You should be able to assess wear/slop in the drive shafts by firmly clamping the shaft (eg moles, themselves anchored) and rocking a wheel by hand.

I know it's a generation apart, but our BX here had clonky/clicky UJs/CVJs on both sides when I took it in, and a hefty injection of molybdenum grease (via a short length of 5mm poly pipe on the end of the grease gun, pushed all the way into the gaiter, right up to the bearing) has silenced all four joints completely. Your Leaf is no age at all, I realise.

[Mandrake]

I have two more pearls to throw in the ring at this point:
1) I think there are two distinctly different faults involved in this discussion and the videos we have seen, firstly the click which occurs when the direction of force is altered, ie between accelerate and overun or stationary to forward or reverse motion and secondly the consistent rotational clicking that is apparently gearbox related.

Yes two different faults with different causes.

The single click on change of torque direction is (supposedly) the stub axle moving slightly in the hub - which this car has had ever since I bought it and is a very common Leaf problem. I say supposedly, because a few weeks ago I followed the Nissan TSB to re-grease the spline - which involves removing the stub axle nut, tapping the stub axle back a bit (it can only move about 20mm) then greasing the rear of the spline area between the hub and joint. Didn't seem to make any difference on my car.

The second problem is the continuous clicking with rotation with torque in one direction. I've already confirmed to my satisfaction that the driveshafts are not responsible for the continuous clicking.

I've been giving it quite a bit of thought and I think the most likely explanation is breakup of one of the tapered roller bearings on the sides of the differential - not sure if this doubles as the output shaft bearing or whether there is an additional support bearing for the driveshafts separate to the tapered roller bearing seen in the dismantling videos.

When torque is applied in one direction the gear will press against the good bearing, when torque is applied in the other direction it will press against the bad bearing with one or more broken rollers...

The bearings on the other two gears are normal ball races, quite large, and less likely to have failed IMO.

[Mandrake]

Ouch that sounds nasty Simon!

Sure we could get the box out of that if you want to have a go.... got to be easier than an ICE car, surely??

What did you have in mind?

I'm really torn between letting someone else fit a second hand box, or try to get the existing gearbox repaired - especially if it turns out to just be a failed taper roller bearing on the main differential gear which is my current hypothesis. However that would probably require me to get the gearbox out myself first.

I've sent an email to Alpine Transmissions in Blantyre to see if they would considering doing a rebuild/repair of the gearbox - they specialise in manual gearboxes and an EV gearbox is really just a very simple single speed manual box so assuming they can get any needed bearings/gears etc it should be quite a simple job for them compared to what they're used to. I doubt they would be willing to remove the gearbox from the car though being an EV.

I've been poking around under the bonnet tonight and I can see some significant challenges to removing the gearbox on a driveway...

- I can't see how the motor stack could be lifted out without a hydraulic engine lift with a reasonably high reach - and they start at about £250 or more than a 1/3rd of the suggested labour charge for someone else doing the entire job... Also the rear quarter of the stack sits behind the lip of the bonnet opening. The scuttle looks like it will come off to make a bit more room but the stack will still have to be tilted quite a bit forward to clear the opening. On the plus side it looks like the radiator fan assembly comes off fairly easily to give a bit more clearance at the front.

- The bottom cover needs to come off the battery pack to access the high voltage cables to disconnect them - easy on a hoist not so easy on the ground when the front wheels are missing and the car can't drive by that point... I can take the cover off ahead of time but would still need to get under there to actually disconnect the cables.

- It looks like the heat pump/AC system would have to be disconnected as it doesn't look feasible to detach the pump and filter from the engine stack in-situ - this would mean a potentially expensive heat pump re-gas afterwards that would eat into any cost saving of not paying the £675 labour to have someone else do the job...

- I was wondering if it might be possible to disassemble the stack in the car - eg remove the onboard charger on the top first, then the inverter unit etc as shown in the teardown video - leaving only the gearbox and motor. With only that left you have a much smaller/lighter unit left to remove and much more room to work - potentially it would be light enough and small enough by the time it's only the motor and gearbox for two people to just reach in and lift it out or lift it out with some ropes/chains.... However I can't tell if this is feasible or not because while many of the bolts are accessible in-situ in the engine bay there might be some that aren't and that would completely scupper that plan and might not be discovered until you're fairly far into disassembly. As far as I can see in the Nissan service manual, they only describe lifting the entire stack out and disassembling it on a workbench.

I really can't make up my mind what to do here... I'd rather someone else do the job but I'm a little bit wary of a random 2nd hand gearbox being fitted - what if the replacement box has a whine for example. I'd feel more comfortable with the existing gearbox being rebuilt especially if it's a straight forward obvious problem like a failed bearing and the gears are all ok. I'm suspecting that a rebuild would be significantly cheaper than a whole box as well.

But it does look like quite a big job - significantly bigger than than the cell swap I did on the Peugeot, and without some way to lift the stack out probably impossible. I'm also not happy about the thought of disturbing the heat pump circuits and having to re-gas them.

Then of course there's the smaller stuff like having to refill and bleed the cooling circuits (not sure if a diagnostic tool is needed to activate the circulation pump like it is on the Ion) do the wheel alignment after removing both driveshafts and hubs, also if I remove the scuttle it looks like I'd need a cover to go over the car as it will be sitting outside and rain water would run straight down into the motor bay without it. If I was working indoors with a nice large, flat floor it would be a bit of a different proposition - I hate trying to do invasive, multi-day work like this outdoors.

[mickthemaverick]

Having studied the videos more I wanted to confirm that the gearbox is mounted to the right end of the motor looking from the front. In which case is it not possible to get the car up on ramps, remove the under cover and then jack the nearside wheel up so you can remove the nearside driveshaft, then replace the wheel and lower back onto the ramp. Then support the motor housing under the motor side half of the transmission and remove the motor mounting completely from the car. Then remove the parking brake mech from the top and any cables leaving sufficient space to pull off the outer cover of the gearbox. Obviously the job will have to be done from underneath but having removed the outer cover you should be able to diagnose the actual problem and then go from there. Unless of course there just isn't room due to the chassis or something preventing access from that direction. If that is the case then I've just wasted yoiur time reading this but I thought it worth suggesting!!

[white exec]

Simon, I think I would be trying to get a few of quotes for replacing worn parts (wherever they are). It's then down to the repair shop to diagnose and fix, and the job will also be warranted.

There look to be potential complications in doing the job on the drive, even though you're pretty resourceful in coping with that.

If it is a taper-bearing problem, the end-float/bearing loading must be set up really accurately (can be fractions of a 'thou)
for the assembly not to float or suffer premature wear. It's not usually just a matter of dropping another bearing in.

Wonder whether the lubrication of the 'box (splash/pump/the oil type itself) was got right by Nissan from the off. Wouldn't be a first time that a gearbox lubrication had needed rethinking.

[NewcastleFalcon]

Obviously the job will have to be done from underneath but having removed the outer cover you should be able to diagnose the actual problem and then go from there. Unless of course there just isn't room due to the chassis or something preventing access from that direction.

I would think this screenshot from a fluid change video would look hopeful from a "remove the box only" point of view unless some of the retaining bolts are at the top and inaccessible without removing the gubbins above.

Screenshot

Screenshot only

Regards Neil

[NewcastleFalcon]

Of course the NISSAN official guidance envisages an altogether more awful set of procedures to remove the "gearbox".
Very Haynes-esque reading and very very off-putting requiring lets say dismantling of everything. So to remove the gearbox their method is to in old fashioned language, drop the subframe with everything attached (car up on a lift subframe dropped onto heavy duty jacking platform and lowered to ground level).

Is it too early to say surely that has to be a load of unnecessary work, and well worthy of an MBE if the home mechanic could ever follow all of those steps.

The Mick method surely has to work, and if it doesnt I would abandon all ideas of taking the engine out yourself.
Electron garage may well be your best choice.

I may have got it all wrong but this is what I gleaned from the "official instructions"

Regards Neil

[Mandrake]

Having studied the videos more I wanted to confirm that the gearbox is mounted to the right end of the motor looking from the front.

The gearbox is on the near side of the car and sort of lies on its side with the differential output towards the back of the car and the input shaft towards the front.

In which case is it not possible to get the car up on ramps, remove the under cover and then jack the nearside wheel up so you can remove the nearside driveshaft, then replace the wheel and lower back onto the ramp. Then support the motor housing under the motor side half of the transmission and remove the motor mounting completely from the car. Then remove the parking brake mech from the top and any cables leaving sufficient space to pull off the outer cover of the gearbox. Obviously the job will have to be done from underneath but having removed the outer cover you should be able to diagnose the actual problem and then go from there. Unless of course there just isn't room due to the chassis or something preventing access from that direction. If that is the case then I've just wasted yoiur time reading this but I thought it worth suggesting!!

There's a couple of problems with that suggestion - one is that there is a large bracket above the parking brake actuator which has a bolt at one end and seems to be riveted to the casing at the other end. So it's not possible to remove the parking actuator without first removing the onboard charger and drive inverter from the stack. I wonder which genius designed that bit.

The other issue is that you can't separate the gearbox and motor while the inverter is still bolted to the top as the inverter bolts right across the pair of them helping to join them together. If it's not the parking brake at issue I'm not sure I see the point of this anyway.