Oil leak - 2012 Duratec with Caterham 6 speed box

[Dan R]

The leak will show as a small patch on the floor after a blat that doesn't get worse over the time its parked.  After looking underneath it seems to be coming from the rear of the gearbox? Propshaft seal? Unless anyone can advise differently?  Im also presuming this can be replaced with the gearbox in situ?

Additionally is there supposed to be anything in the recess indicated by the arrow??

[Amos91]

Both are pretty normal leaks really as far as Caterhams are concerned. It will be the prop seal in the left. 
 

I believe the arrow points to where the speedo sensor would be if it used that. 

[ScottR400D]

Yes the arrow points to the speedo drive hole, it should be blanked off. 

My 2015 car has always leaked a little from the gearbox tail seal. It runs down the flat underside of the tail, gradually builds up on the round part near the speedo hole and drops from there. 

I get the impression that it doesn't leak whilst driving but when stopped after a run and just a few drops if that. If I clean it there'll be no drop to the floor for a few drives then it will drop a little. 

I change the oil every year or two and there's never any noticeable drop in level. 

A couple of years ago when I changed my diff, I had the prop out to check it. I thought that might send the seal over the edge but in fact after reassembly it was better for several months with no leaking then but gradually began again. It's no worse now than 5 years ago.

I've never even considered changing it but think it would be tricky in situ. It needs to go in very squarely, hard to do in situ. 

[Dan R]

Thanks both. 

This has only just started leaking and it is not much and appears to be briefly after a drive and not constant. 

As for the speedo drive hole, i cant remember how it looked inside the recess now so will need to have another look underneath.  Should it be blanked off flush with the casing? (ie no recess visible)

My thoughts were to get the seal etc looked at when i have the diff out. 

[ScottR400D]

The blanked hole looks right. When you build a car you have to tap in the black steel plug just as you show. 

[Dan R]

[Wrightpayne]

I hope you dont mind me saying but your shaft doesn't look very far in the hole :-0.

This is my '98 K imperial chassis with 6sp. I would expect the further out the prop is on the splines the more potential for up/down movement (as opposed to in and out which is OK)

I think it would be useful for other members to post pictures of their shafts for comparison, particularly duratec owners!

 

[Dan R]

There is endless scope for comedy here!

Im not sure if it makes a difference that mine is an SV? 

[Wrightpayne]

In all seriousness it does look a long way out by comparison and scope to twist laterally which is likely to affect the seal - I wonder if there is a part code on the prop to check it out or maybe measure it and post (insert your own pun!) so can compare to others cars.

I've had a 5sp and a 6sp in my seven with the same prop.

[Dan R]

I will see if i can get chance to get underneath it again tomorrow and measure the prop and post my findings.  Be interested to see if any other members have the same length and/or insertion issues! 

[Wrightpayne]

Just to add, on a dedion there is little/no movement in/out on the prop/gearbox splines, as all the components are fixed. There will be more on a live axle as the whole axle moves in an arc

[Dan R]

So after measurement, the driveshaft is 60cm from flange to flange. Not including the insertable length as in the picture.  (There really is comedy mileage in this)

[SM25T]

Propshaft ?

[7 wonders of the world]

there's no flange of the front of a 7 prop it utilises a nose and spline off the UJ yoke so not sue where you are measuring too for comparison..?

[Geoff Brown]

I could say 'that they all do that sir' but truthfully my six speeder produces a few drips of oil after an extended run exhibiting all the signs that others have mentioned. 

The annual oil level check has always been OK indicating a very, very small oil loss.

Unless the front of the diff & the surrounding frames are absolutely dripping then fear not.

 

[ScottR400D]

There have been a few different props sold with these cars, I understand. Different tube lengths giving different amounts of shaft showing at the box, some with grease nipples, others without. 

[Dan R]

#14 Sorry, for clarity its from the flange at the rear and to the forward part of the UJ at the front 

[Dan R]

#15 Thanks Geoff!

[Dan R]

#16 That's handy.  Its always nice to have some additional ambiguity, and thankfully CC never fails to deliver ! 

[mph]

I had exactly the same thing Dan R… https://www.caterhamlotus7.club/forum/techtalk/gearbox-oil-leak-concerning

It did turn out to be a seal on the gearbox, which has been replaced now and no longer leaks.

Diff now leaks though

Can't win 'em all, eh.

[Dan R]

#20 Thank you MPH.  My plan will be to get it done while the diff is out.  Assuming it can be done with the gearbox in situ..... otherwise it may need to wait!