Gearbox front oil leak

[KiwiTR6]

I have pretty much eliminated all of the oil leaks from my car other than what is definitely a leak from the front of the gearbox evidenced by a constant slow leak of transmission oil from the weep-hole in the base of the bell housing.  There is no doubt that it's the transmission oil I recently installed.

I've had the gearbox out 3 times already and I'm not keen to do it a fourth time due a back injury, but I will do it again if there's no other option.  However, I think I may be able to solve the problem without having to do that.

The gearbox has been rebuilt as I've posted previously and my initial thought was that the input seal may not have been installed correctly.  However, when the car is parked (from what I can see) the oil level should be below that so I'm now thinking the seepage is possibly past the threads of the seal housing lower bolts (or the gasket).

Ideally I'd remove the box and replace the current washers with some Dowty type, the gasket and the seal regardless, but I think from the photo below (courtesy of Bullfire.net) I should be able to access the open holes and seal them just by removing the top of the gearbox.

Has anyone else tried doing this?

 

 

[John L]

I have always used copper washers on the bottom cover bolts, and made sure that the circlip that holds the input bearing is aligned with the drain slot, make sure also that there is no forward rearward movement of that bearing, that can pump oil thru the seal.

John

[KiwiTR6]

Thought I should provide an update now that the job is completed.

My initial hope was that I might get away with just blanking off the internal bolt openings which I did using JB Weld and then a thin layer of 3 Bond 1104 over the top to be sure.  The lower two holes were really awkward to get at but I managed in the end with a bit of discomfort and ingenuity.  The two very bottom ones for the bolts that secure the little cover plate were impossible to access.

Anyway, it was a fruitless exercise in the end as the leakage persisted after this so the gearbox had to come out after all.  The main cause appeared to be the input shaft seal having being pushed  fully home by my local repairer leaving only one of the two lips in full contact with the shaft (the other was on the shaft taper).  I had read somewhere that this is a bit of a trap so I new what I was looking for.

The copper coated washers were also in a pretty bad state so in total it was possibly a combination of several leak points including the gasket on the bottom cover plate.

I fabricated two new gaskets, installed a new seal (from the local engineering shop - slightly narrower than the one that came out but otherwise dimensionally correct) so that both lips would be in full contact with the shaft, and reassembled all using dowty washers on all of the bolts.

I'm happy that it should now be oil tight and so far there is no sign of leakage after a couple of short trips.

Some photos attached for those who may be interested.

 

[RogerH]

I do not understand why the counterbore where the lip seal sits is so deep.

I remember a few years back this happening to me.

I made a packer to stop the seal moving in further.

 

Roger

[stuart]

14 minutes ago, RogerH said:

I do not understand why the counterbore where the lip seal sits is so deep.

I remember a few years back this happening to me.

I made a packer to stop the seal moving in further.

 

Roger

Possibly because it had been "reclaimed" by someone who had gouged the life out of it trying to get the original seal out, Ive come across seal housings with lots of deep indents due to this, Ive replaced with new housings to cure it.

Stuart.