Gearbox SOS

P

Phil_the_Chill

I have a 5 gear K10 1.0L.
The box is shot so I got a replacement and figured I'd swap it.
The operation looked tricky but do-able.

I have lifted boxes in before but usually with my dad.... I found the single handed hoiking quite a damned struggle...


Then... it all got worse... the drive shaft gears plopped into the box!!!!!!!!!!
Yes I had read the Haynes manual and they suggested broompole lengths to keep them in place.. the scrapyard guys had stuffed rag in the holes.. and as the gears were still in place I took a risk.

Now... I guess I have to open the box and put them back in position??
There is also a couple of washer type things floating around.

Any suggestions how to proceed and is there a knack to waggling the thing back on the driveshaft.. Help!! I need the car for a funeral on Tuesday.

Thanks

Phil
 
Argh God... what have I done?? I opened the old gearbox... and quickly deduced that I'll never be able to get the side gears back in... without lifting out the differential assembly... I can't do that it looks too major for me.

So.... options? Gynaecological fiddling of side gears back into position without opening the box??
I am thinking of asking the scrappers for a replacement box.. as they didn't lock the gears in position as suggested by Haynes...

Any ideas?

Ta
 
i never had that problem when i changed my 4 speed to a 5 speed or even heard of it before so i cant help much, the scrapyard put rags in to stop any oil leaking out. are you talking about the diff in the gearbox as i cant see how it would drop.

my advice would be to use a screwdrive to try to lift it up being careful not to damage anything but if its not moveing i wouldnt force it

sorry i cant be off more help
 
Yes the rags were to keep the oil in. The short lengths of broompole are clearly necessary... as I have now learned. There is just enough room in the differential case for the side gears to fall out of position.. (with the thrust washers).. ahh yes the real cruel bit is that is not enough room to wangle them back in again. I spent a good 4 hours tilting it this way and that and while i could get hold of a thrust washer.. and put it in place.. I can't get the gears past the other two on the differential axle. Then the thrust washer drops out again and.. the cursing starts. I had one gear in at one moment.. but you need to get all 4 adrift components back in position and I have come to the hard conclusion that it is impossible. It is like a giant kids ball-bearing puzzle but much less fun.
 
If dismantle the box and lift out the differential.. is it a disaster?
I read about issues like preload (???) About which I have no idea.
I mean.. if it is a simple.. remove.. replace... reassemble.. then I might go for it. I have the old box for practice. But.. if there are additional steps that I can't carry out then.. no way.

Advice anyone? Thanks.
Interestingly... the side gears on the old box are still happily in place.. despite much manhandling.
 
Don't worry about preload on that box, you have just experienced a rare and very annoying thing that can happen on these boxes. Just pull it appart and sort the diff. It will be fine :)
 
Thanks for that Ed!
I had come to the same conclusion after finding the service manual online.. very useful that chap!!

I just want to undo the minimum to lift the final drive out and rebuild..
so... following the medical dictum "first do no harm" I have to figure out what bits to undo to lift the gears enough to achieve the result and no more.
The service manual has the diagrams and I am printing now.

"I may be some time" Cpt Oates
 
You should be ok, though to be honest its ages since I split a stock K10 box so I cannot remember the specifics! The diff is pretty simple to straighten up however once its out.

Ed
 
I did the box. It was not tooo bad. I took pictures along the way.
I eased the drive wheel out and fixed it.
Good God.. it was quite hard out of the gearbox... utterly impossible with it in .. that's now clear. Seeing it is a lot clearer than a diagram. For one thing the two side gears have to be exactly opposite (natch). And it is quite tricky to get them in with the thrust washers as well.

I have reassembled and the gears turn ok... but...
the selector mechanism seems locked. I don't know whether this is because I haven't got the leverage of the gear stick assembly to assist me or if it is really badly assembled after all. I don't fancy putting on the car only to find it then doesn't work.

Should I be able to work the gears just using the gear change rod attachment point?

Ta
 
At a guess - id say you SHOULD be able to, but it will be difficult due to the lack of leverage.. i know that i have had to select a gear from under the car when the gearlinkage broke on Kristians and mine R5gtt.
 
Thanks for that. I am suspecting some problem in the re-assembly. It works fine until the cover goes on. This will bring up the shaft ends to the proper position and perhaps revealing the misassembly when the slack is taken up.
I've cracked the box twice more since to try and pin it down.
The manual is also vague about the order of re-assembly.. there are a few return spring dohickeys with secondary spring-loaded ball bearings that can go pearshaped if put in out of order. All this ... and then the hoiking up onto the clutch!! argh!!
 
with nothing more than a screwdriver in to assist you should be easily able to change the gears..
 
Hi Ed, Yes it proved ok in the end after a bit more brute force was employed.
I was glad I dismantled though as I found the reverse gear on the shed floor.. oops. Managed to heave it onto the car and just need one more drive shift putting in. I found that part extremely difficult.. one of em just won't go.
I dressed the end with a file and carried on.. but it is proving very stubborn.
All in all it has been like running a marathon. Definitely the dirtiest and most frustrating car task I have ever undertaken. Course it would have been a lot better if the differential hadn't dismantled itself.
 
I think I have done the gearbox change 3 times, and it was pure luck that the diff didn't do this. It did happen on one of the ones that was removed though.
 
I have no idea how many I've changed, never yet been a problem. I think you can run in to issues if one of the shafts is out and the other is turned, I'm sure ill run into this problem oneday :) haha if not on a box I remove but one that I replace it with that didnt have a bar or something through it.
 
I am happy to say I put it together at noon yesterday and just flogged for 260 miles on the motorway and it was spendid! The driveshaft problem was overcome by using something larger than a toffee hammer to drive it home.
A tad stiff and I was worried about mushrooming the end.. but it went in.
Thanks for useful comments.
 
Bit of a followup...
My gears are stiff to change compared to my other K10. The main problem though is that there is a helluva vibration coming up the gearstick. It isn't a lubrication problem as there is plenty of oil in the box. Is there something else that could lead to excessive vibration? Some nut on the box that needs flogging up? Some misalignment on the selector? It is really quite a rattle.
Suggestions welcome. It bothers me so much that I am prepared to get a hoist and take the whole thing out again. I wondered if it was connected with the stiff change... it really is quite different from my other K10 which just slips into any gear smoothly.
 
take off the gear linkage and grease it up so its all free moving when putting it back on dont tighten the bolts to tight on the gearbox or you will gear stiff gear changes

then check the 2 rubber gear lever mounts are ok and not splitting if they are you might aswell do them now as its not funny watching the gear lever drop down
 
actually it is more of a serious vibration than my post suggested.. the whole car rattles and the gearstick just conducts it more... holding it still the dash still buzzes and rattles... seems to be the engine or something It just ain't right. Could it be camshaft bearings?? I mean could something like that produce a serious rattle? It is as if there is an imbalance in some part of the system.. gears, flywheel something.. it definitely gets worse when the gearbox is attached to power.. but then it could be just receiving the vibration from the engine and amplifying it. Not sure how to proceed really.
 
Hi sonic You'll have to forgive me if I'm slow.. I never did a gearbox before.. lol but well I didn't take the clutch off just waggled the gearbox drive shaft back in the hole and flogged it up again. I did have some concerns that struggling singlehanded I might have let the box hang on the driveshaft and pull things out of alignment but I guessed that when it was in place and tightened up it would self-center whatever had shifted about. I reconnected the clutch cable but didn't worry about it.. I figured if it was too tight it would slip and if loose I would know it. Vibration? I just can't understand what the source would be. It feels like some imbalance somewhere. Can you get vibration from the clutch? I certainly didn't take the clutch housing off or anything.. just straight off with the box and on with the "new" one. The ignition system seems to contribute to the problem.. I have had an ongoing problem with timing and smooth running etc.. and there seemed to be an odd knocking at one point which disappeared when the timing was retarded slightly. My timing light is out of commission so it is hard to setup properly. I took a look at the points but couldn't actually find them.. (well I was in hurry) and the guts of the distributor look different from my old K10 .. I need to do that again and maybe get the running as smooth as possible before getting into the mechanical problems. I am sure an expert could listen to it and have a feel and pinpoint the problem straight away. I did have to remove the gearbox case and lift out the main drive to rebuild the differential after a collapse but it seemed ok on reassembly and turned freely. There is plenty of oil in there too.. and the vibration is lower frequency than you might get from a dry box. It is just "rough" could be ignition I guess?? communicating itself through the whole system from the engine downwards. I also changed the timing belt and had some trouble getting the tensioner correctly set.. it was a right swine. The belt was tight one revolution and slack the next.. and the tensioner kept popping the spring out and falling off. .. really frustrating.
I think I will need to invest in some sort of hoist for any future work.. grovelling under the car is no fun and adds hours to the job.
So... yes it is pretty hard to figure out.. I've just never had a car that sounded like this. On balance... I'd say it was mechanical.. and just need to eliminate potential sources one at a time. I just don't know what the sources could be to produce this kind of vibration.
Thanks
 
if you have an ignition problem and it intermittantly misfires or misses on one or more cylinders then it will make the car shudder a bit, I've not done a Micra box myself, but on other cars I've done the clutch has always needed centering to fit together smoothly, that could be your problem, also if you let the gear box hang on a drive shaft it's entirely possible that the drive shaft may have bent slightly, that would make the car shake. As Fordy suggested have you greased all the linkages and is the gear change smooth and slick now ? if you hadn't put the gearbox together properly you would have found out after 300 miles or so like you have done I would imagine.

You couldn't find the points ? what year is your K10 ?
 
No I haven't greased all the points yet.. pressure of work and finding the will to crawl under the car again.. it costs me more in clothes than a garage would charge for the job lol....
Now I haven't got a total mental image of the mechanism but I imagined that the drive shaft engages with the splines on the centre of the clutch plate. Once in place the drive shaft is effectively positioned by the bolts holding the gearbox on and the first time the clutch is engaged I imagined it would then center itself with the drive shaft as reference. Is this feasible?
A bend? I guess yes that would produce the undesired effect.. i just didn't think I could allow sufficient force on it to bend an inch diameter solid steel shaft. Does this happen?
The points? Hmmm I had a quick look with a torch and it just looked different from other "pointed" cars.. the arm was some big plastic affair and I couldn't locate them... I think I will with more of a look. The car is G reg. Ta
 
Ahh that cleared that one up. If it quacks like a duck...
Is this system serviceable? Likely to need replacement etc?
I will look in my Haynes tonight for info.. maybe I can get a scrapyard replacement..
 
if you have disturbed the distributor at all it will upset the ignition timing, that will cause rough running, the electronic ignition is not really serviceable and I've never heard of one breaking , as far as I know it should outlive the car. Just as a matter of interest, the bolts holding the distributor are tight aren't they ?
 
Well one was beheaded by previous owner and stump left in the hole.
I have been trying to devise ways to drill it out and replace. Meanwhile I have a little G clamp holding it together securely. When I got the car it was held on by one screw and lots of insulating tape.
At the time there was the weird knocking going on which seemed ignition related i confess that given the age of the car I assumed it was points and i did loosen and adjust the timing slighty to alleviate the noise and it was smoother afterwards with good pulling power. This was before the gearbox change. I think there are a few things coming together to blight the vehicle. It runs now but doesn't idle smoothly.. there is a regular little hiccup. I just need some free time for a thorough look at it all.
 
Update on gearbox.
I got myself a cheap hoist off eBay and it made the work a lot easier!!
Getting the engine out was quite straightforward.. I didn't need to remove the fan/radiator as the Haynes manual said. One thing worth remembering is to make sure the movement range of the hoist setting is sufficient for the engine to clear the fronr grill! Lol. Oops.. I had to lift it over.
The first thing I noticed was that there was play in the central splined hole on the clutch plate. A few millimeters each way laterally.. is this normal?? Or do I need a new one?
Opening the gearbox... well.... I noticed that the ball bearing/bolt combination that engages with the top end of the selector shaft was slightly wrong. The spring was too short or something and the ball bearing had sunk into the bolt so far that the bolt had been making direct contact with the selector shaft. This most have restrained the free movement somewhat and communicated a lot of vibration. I felt the input driveshaft needle bearing but... well it felt OK as far as I could tell. Having knocked off the reversing switch mechanism I made a mental note to next time make sure I fully remove all bolts from the casing that might clash with it before fooling about.
The clutch is bothering me and as the engine is out I may as well fit a new on if it is faulty.
 
why did you take the engine out to do a box change..also do you mean the diff planet gears fell down,be carefull cus these two shimms that keep the two gears in place.
 
Well i got my new hoist lol and wanted to play with it. Plus it was a lot easier to get it on and off with the engine out.. and there are a few other things to do. An exhaust stud has sheared off, and the timing belt cover has a big hole in it. Actually.. heaving the box in with the engine in place was a ###### of a job last time... you can hold the weight for a reasonable time.. but waggling it into position you soon get tired and have to give up and start again. There isn't much clearance under a jacked car and you get very oily. I could have hung the box from the hoist this time.. but really I just wanted the whole unit out for a good going over.
The only cloud on the horizon? That ####### stud.. which looks like it is going to be stubborn.

Oh yes the planetary gears fell down the first time I worked on a box in ignorance. I was a lot more careful this time. Plus!! I remembered to stuff all the gaps around the gears and main wheel in case a ball bearing dropped out and fell into the box.
I was surprised to find that the reverse switch mechanism is mounted with some really weak rubbery crap!! I cleaned it up and tried epoxy.. er.. I am hoping that when assembled it will be held into place by the casing as well.
http://www.shef.ac.uk/~md1pw/data/mount.jpg
 
Latest news is that my passenger side inner CV is kind of knacked. It won't go in without a helluva lot of hammering and the lock ring won't even sit in the groove. I made an attempt to dress up the splines with a file.. but it doesn't look good. I might try again tonight with a small grinding tool. I am looking to price a replacement.. may as well get the job done right. Also the timing belt cover has a hole in it... the Nissan dealer quoted me about £25 and mentioned that they had also "changed" the bolt design and these were £10 each. I am looking to patch it up now. My local scrapper could be a source for a CV but they are running out of K10s these days...
 
The gearbox is a lot better now. The problem was one of the retaining bolt-spring-ballbearing combinations that engage with the selector shaft.
It is now quite clear that the one involved must not be screwed entirely into the threaded hole but needs to be backed-off somewhat or else it locks the selector shaft solid. I have the feeling that there was supposed to be a washer on it to achieve just this effect... perhaps a washer with a bendable tab that also serves to hold the reverse light cable?

Anyway.. it is all back together. The only slight niggle is a vibration that kicks off when the mainbeam is turned on. This is no doubt coming from some kind of relay box on the passenger side of the engine compartment. I don't know what is causing it .. and it is possible I have dislodged some critical wire. Ideas? Thanks.

Ah yes... I er searched the threads and found that I am probably suffering from a short circuit somewhere in the lighting wiring. I will consult the Haynes for possible problems.
I put tape on the wires when dismantling to indicate where they go... necessary as I am colour blind... but I could have got one mixed up...
There is definitely one left over.. with an eye in the end so it must go somewhere! Everything seems to work though... lol 'cept for the mainbeams!
They come on.. but this damned buzz kicks in so I turn them off immediately!
 

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