JB3 leaking input shaft

[JezzaMac]

I have a JB3 gearbox in my DCI just now. I've had problems with the car leaking engine oil through the gearbox but I've replaced the crank seal and flywheel bolts twice and it seems to have stopped leaking engine oil.

However it has started leaking gearbox oil out the bottom of the gearbox. I'm pretty sure it's coming from the input shaft and not a crack somewhere. I was hoping that it's like a JC5 where you can just pull the cover off the shaft and replace the seal but it's clear that it's going to be a split the box job!

Now I'm fairly handy with a spanner however I have never split a gearbox open. My question is: is it possible for me to do this as I would love to learn or is it a specialist job?

Cheers

 

[NorthloopCup]

Depends on what tools you have available and what your level of skill/experience is mate. If it's anything like a jc5 to strip you will potentially wish you'd never bothered! Lol

 

[JezzaMac]

Depends on what tools you have available and what your level of skill/experience is mate. If it's anything like a jc5 to strip you will potentially wish you'd never bothered! Lol

Depends what tools are needed! If it's just spanners, sockets that kind of thing then I have all that. If it's specialist tools then I might be able to borrow them from my friendly Renault specialist garage!!

Skill wise I'm fairly practical and fairly good at looking at things and working out where things should go. If there are clear diagrams and things kicking about that would be good.

My only concern is opening it up and s**t pinging all over the place! Haha

 

[NorthloopCup]

Depends what tools are needed! If it's just spanners, sockets that kind of thing then I have all that. If it's specialist tools then I might be able to borrow them from my friendly Renault specialist garage!!

Skill wise I'm fairly practical and fairly good at looking at things and working out where things should go. If there are clear diagrams and things kicking about that would be good.

My only concern is opening it up and s**t pinging all over the place! Haha

It's mainly pullers that you'll need mate. When you split the casings you need to manipulate the selector lever as well to get it to allow the 2 halves to part. It's when you put the 2 halves back together that you get the best bit. Trying to get the selector into the correct position!!
Its about as much fun as appearing in a ISIS video tbqfh. The manuals are knocking about on stripping them if you do a search.

 

[JezzaMac]

It's mainly pullers that you'll need mate. When you split the casings you need to manipulate the selector lever as well to get it to allow the 2 halves to part. It's when you put the 2 halves back together that you get the best bit. Trying to get the selector into the correct position!!
Its about as much fun as appearing in a ISIS video tbqfh. The manuals are knocking about on stripping them if you do a search.

Sweet so you recon I should be able to get the box split easy enough after I break the selector leaver? Haha

Might give it a bash tomorrow and see what happens.

As long as nothing pings out as soon as I start to split it!!

 

[barnesautos]

Did I reply to you on the FB site ?

JB3 box is a doddle to strip .
It's just getting the 5th gear off without breaking it or even chipping the teeth . .

Once 5th gear is off - your pretty much there .

Only thing your need to do it select reverse gear first with the lever outside of the box and then push 5th gear down so two gears select at the same time and locks the box .
Once the bolts are loosened . Un select both gears b4 you proceed any further .

 

[barnesautos]

Sweet so you recon I should be able to get the box split easy enough after I break the selector leaver? Haha

Might give it a bash tomorrow and see what happens.

As long as nothing pings out as soon as I start to split it!!

Don't forget to us a magnet up against the 3rd and 4th selector rods . That should catch the two ball and springs as your prizing the casings apart .

 

[barnesautos]

 

[JezzaMac]

Did I reply to you on the FB site ?

JB3 box is a doddle to strip .
It's just getting the 5th gear off without breaking it or even chipping the teeth . .

Once 5th gear is off - your pretty much there .

Only thing your need to do it select reverse gear first with the lever outside of the box and then push 5th gear down so two gears select at the same time and locks the box .
Once the bolts are loosened . Un select both gears b4 you proceed any further .

What do you mean 5th gear off? Bear in mind I've never opened up a box and never really seen the inside of a box either.

So select reverse with the leaver on the bottom and then how do I push 5th gear down after that?

Then loosen all the bolts around the outside, deselect reverse and 5th.

Then where do I put the magnet before splitting the box?

Cheers for your help!

 

[barnesautos]

See that little half moon metal bit , behind that is the ball and spring that holds reverse up. If you look at it you should see a spring poking it's head out up against it .
Don't touch this until you have removed the 5th gear and idler drive gear which under the end cover .

 

[barnesautos]

Here are 5th gear and idler gear which need removing first .

 

[barnesautos]

See that plastic bit at 12 o'clock in the pic . DO NOT BREAK THAT . That is 5th gear oil feed and if broken will need to be replaced or 5th gear will seize up and box with stop .
See the shaft at 5-6 o'clock that's 5th gear shaft , after selecting reverse , just pop 5th downwards and hey presto two gears will be engaged . Undo the bolts in the other pic which contains the fork for 5th gear. Deselect the gears is a must at this point .
Ok so now the tricky part . Removing the 5th gear . This can be very hard and extremely delicate .
What we used to do back in the day was use a rubber mallet and welt the top of the 5th gear shaft with the bold screwed into it again without the washer . Some will highly disapprove at this point and say oh no you've got to use a special tool . That's the correct way yes - but my way I've been doing for ever and a day works for me .
No damage has ever occurred to any gearbox
I've repaired in the past and I did my 172 box this way with no issues .

 

[barnesautos]

Here are 5th gear off the shafts . Do not separate them try to keep them all together .
Under the gear on the left is a gold synchro ring and spring



Mark the inner hub and outer sliding ring with tipEx / paint so if it falls apart you can place is back in the exact previous sliding position as before , this is vital as it's been selecting and sliding so the two are well worn in together now [emoji6]

 

[JezzaMac]

Ok well this is where I've got to. I only have one gear at the selector on the bottom of the box and yea I don't really know what shaft I'm ment to be trying to push down lol.

 

[barnesautos]

You clearly haven't read my post properly .

Why have you removed the 5th gear fork ?

 

[barnesautos]

Only thing your need to do is select reverse gear first with the lever outside of the box and then push 5th gear down so two gears select at the same time and locks the box .
Once the bolts are loosened . Un select both gears b4 you proceed any further

 

[JezzaMac]

You clearly haven't read my post properly .

Why have you removed the 5th gear fork ?

Yea I f**ked up! The long shaft at the bottom of my picture i've pulled too far out by accident and now cant get it back in.

When I pull the selector down I can swing it back and forward but that's the only movement I can get.

Doh! Oh well I am learning how not to do it!

 

[barnesautos]

View attachment 114544

View attachment 114545

Look at these two photos very carefully ,
The rod in the second pic is the one you have pulled out to far .
You can see it has a
Fork bit at the bottom of pic 2 ok.
That rod is 5th gear selector rod .
Can you see it slots in to the hole at the bottom of the gear set in pic one above .
You need to try and turn the rod as it will only slot in once in the right position .

 

[barnesautos]

All is not lost . If you cannot get the rod back in , just rebuild the 5th gear so it looks like this again without the fork .

View attachment 114547

Then select reverse gear FIRST which is the lever away from the casing at the bottom and towards the rear of the box starter motor side . Then manually select 5th gear with your hand so it looks like this , I mean push down on the round selectors so it dogs in 5th

View attachment 114549

Ok [emoji106]

Then you can undo the nuts accordingly .

 

[JezzaMac]

That's me got the shaft back in and reverse selected but the cogs at the top are still turning. Do I need to push the 5th shaft down more?

Thanks for your help btw dude! Much appreciated! [emoji106]

 

[JezzaMac]

Hope ive not ruined this box!!

 

[barnesautos]

The reason both shafts turn still is because your missing the selecting ring bit that goes over the 5th gear in your pic .
From the bottom it gear , synchro ring , hub . You sliding hub ring locks 5th gear in when push down , like the rod would do .

 

[barnesautos]

Get it looking like this , but select reverse first ok

 

[barnesautos]

You haven't ruined it

 

[JezzaMac]

That's it all locked up the top now! Woop!

 

[barnesautos]

That's it . [emoji106]

Up a 5.30am I'm off

 

[JezzaMac]

so let me get this straight before I continue tomorrow..

Remove the top nut on 5th gear and remove all the bits and bobs
remove the bolt on the top of the other one and remove the gear
unselect reverse
remove spring and bearing from reverse
put a magnet next to 3/4 selector rods which are the other two rods next to the one that I pulled too far out
remove all the casing bolts and start to prise it apart
then the input shaft seal will reveal itself and be easy to remove right? lol

 

[JezzaMac]

That's it . [emoji106]

Up a 5.30am I'm off

Thanks a lot mate really appreciate it! il let you know how I get on tomorrow!

 

[barnesautos]

so let me get this straight before I continue tomorrow..

Remove the top nut on 5th gear and remove all the bits and bobs
remove the bolt on the top of the other one and remove the gear
unselect reverse
remove spring and bearing from reverse
put a magnet next to 3/4 selector rods which are the other two rods next to the one that I pulled too far out
remove all the casing bolts and start to prise it apart

That's correct up to this part .


Now you got to remove the 1/2 -3/4 gear set along with the selector forks all as a unit .

The forks are roller pin secured to each rod .
These need removing so the rods can be twisted within the forks and lifted up one at at to be removed and layed to one side .
The shafts won't come out unless reverse idler gear is up and close to it's natural living position . That big reverse shaft moves up and down and pushes interlocks between the two other shafts and there is a tiny sliding piece within the casing / shafts .
DO NOT LOOSE THESE.

 

[JezzaMac]

Progress is being made! Have managed to strip the box thanks to Rentec Edinburgh that helped me pull the gear off on the top of the shaft!

They also loaned me a couple of dummy shafts which will make it much easier to put the rods back through the casing while holding the springs and bearings in!

Now just to work out how to actually get the seal out and replace that then trying to put the thing back together again [emoji23]

 

[barnesautos]

Before you press the input shaft bearing out - be sure to measure the drop from the casing to the back of it as this is important , because there is an oil feed hole in the casing that'll need to be lined up perfectly when pressing it back in . The oil feeds the bearing naturally . Any off centres and it'll starve of oil .

 

[JezzaMac]

Before you press the input shaft bearing out - be sure to measure the drop from the casing to the back of it as this is important , because there is an oil feed hole in the casing that'll need to be lined up perfectly when pressing it back in . The oil feeds the bearing naturally . Any off centres and it'll starve of oil .

Right I understand that so that the earring goes back into the same place it comes out!

What's the procedure from here to get the bearing and the seal out?

Il be replacing the bearing at the same time as the seal. Also long to do the 5th gear oil feed!

 

[barnesautos]

Right I understand that so that the earring goes back into the same place it comes out!

What's the procedure from here to get the bearing and the seal out?

Il be replacing the bearing at the same time as the seal. Also long to do the 5th gear oil feed!

The seal is inside the tube and the bearing is all one piece .

View attachment 114632

See the white bit in the inside of the tube ?

When you get yours DO NOT REMOVE THIS .
what you need to do is press this out with a press machine .
Remember to take note of the drop of the bearing height in the casing .
See the hole in the outer casing of the bearing ?
That's the oil feed .

When it's pressed in to the gearbox casing and ready for rebuilding , put a drop of oil around the input shaft itself and when offering all three shafts in at the same time the input shaft will push the red bit out no problem.

 

[JezzaMac]

The picture didn't work dude.

What way does everything press out? Does it come out gear side or bell housing side?

I don't have a press but is there anything a can buy/make to do this or am I better going to Rentec and getting them to do it properly?

 

[barnesautos]

Call Ren-tech , ask them how much it'll be ?
It'll save a hell of a lot of time .
You could have it all back up and running by the weekend. .
Also you need to get the sealer that goes between the casings ?
Again ask Ren-tech what they use

 

[NorthloopCup]

It's loctite 518 for between the casings.

 

[barnesautos]

It's loctite 518 for between the casings.

The Red stuff [emoji106]

Had shed loads back in the day .
Might have a tube kicking about .
I'll have a look

 

[NorthloopCup]

The Red stuff [emoji106]

That's the stuff mate. It also never sets fully.

 

[barnesautos]

That's the stuff mate. It also never sets fully.

That's right - always remains tacky .

It was also used for all water pumps too would you believe .

 

[NorthloopCup]

That's right - always remains tacky .

It was also used for all water pumps too would you believe .

And the cam cover! Lol