gearbox oil leak

[pierce]

Hi,

I have noticed a couple of drips of oil under my rhs cv joint appearing after I have been driving and park up.

I am assuming that oil shouldnt be getting as far as the cv joint so its probably the drive flange oil seal, is this a fair assumption or could anything else cause oil to drip from here?

Thanks in advance

[slowcoach]

same thing on mine, ive been told that on mine it is the 'input selector shaft seal' ? that is at fault.. its coming from that side at least...

[pierce]

same thing on mine, ive been told that on mine it is the 'input selector shaft seal' ? that is at fault.. its coming from that side at least...

Could be, thanks slowcoach, although it definately seemed to be dripping from the cv joint; I think I am going to have to clean all the oil off to get a better idea, seems to be a fair bit of oil around the front of the gearbox too.

[pierce]

I have given it a clean today, hopefully I have removed enough of the oil to be able to tell where its coming from.

I have ordered both the input selector and drive shaft oil seals, hopefully they will arrive before Sunday.

Now there doesnt seem to be much information on the input selector oil seal in the haynes, has anyone done this job, any pointers?

Cheers

[CovKid]

I've done that job

Its your output shaft seals buddy. Easier with box out but can be done in situ. Heres my explanation with pics:

https://club8090.co.uk/wiki/Ge ... eak_repair

[pierce]

Thanks CovKid,

Think I will take the gearbox out, so I can work on it in the kitchen instead of under the van.

[CovKid]

Just bear in mind that if there is appreciable wear in the output flange (ie with driveshaft removed you can move flange up and down noticeably), the seal replacement may be short lived. Mine had a little wear but not had a leak from that area in over a year since I did it. The Haynes explanation is horribly vague so I added a pictorial explanation for anyone wanting to tackle that job. On a very old gearbox showing signs of age all over, its probably not worth doing but apart from the work, its a cheap enough fix. I hated the drips too.

[pierce]

Just bear in mind that if there is appreciable wear in the output flange (ie with driveshaft removed you can move flange up and down noticeably), the seal replacement may be short lived. Mine had a little wear but not had a leak from that area in over a year since I did it. The Haynes explanation is horribly vague so I added a pictorial explanation for anyone wanting to tackle that job. On a very old gearbox showing signs of age all over, its probably not worth doing but apart from the work, its a cheap enough fix. I hated the drips too.

The pics are great, there is nothing like knowing what to expect before you do a job.

Fingers crossed the wear isnt too bad. As a whole the gearbox feels ok, I changed the gearbox oil for 80W90 and its a bit hard to get it into 2nd and 3rd when cold, so might go for a thinner oil this time.

[HarryMann]

Semi-synth 75W/90 is about right. When freezing cold you will have to accept a slow draggy change or follow hints 'n tips in Wiki... stay in low gear longer, skip 2nd (usually the crunch change) so go 1st to 3rd until box warm, or pull away in 2nd

Can't be expected to drive it same in freezing temps as mid summer, until its all fully warmed up, so compromise technique for first 5 or 10 minutes
And of course another reason winter fuel consumption can be 10% more than summer

Main thing with those drips, and especially from joins in the case, is box oil level will get low and then the box will pack up completely, effectively destroyed, not uncommon

[pierce]

Semi-synth 75W/90 is about right. When freezing cold you will have to accept a slow draggy change or follow hints 'n tips in Wiki... stay in low gear longer, skip 2nd (usually the crunch change) so go 1st to 3rd until box warm, or pull away in 2nd

Can't be expected to drive it same in freezing temps as mid summer, until its all fully warmed up, so compromise technique for first 5 or 10 minutes
And of course another reason winter fuel consumption can be 10% more than summer

Main thing with those drips, and especially from joins in the case, is box oil level will get low and then the box will pack up completely, effectively destroyed, not uncommon

Ok cool, I will give 75W90 a try.
Good point about the oil level, it would be nice to not have to worry about it.

[pierce]

I have had another look at the gearbox today, it also seems to be weeping a bit from oild grain plug and the two bolts at either side of it, appologies for the bad pic, but you can see it below.

I guess the gasket needs renewing? Is this a job I can tackle at the same time as the oil seal?

[Aidan]

gasket change not a problem, easiest to remove the bellhousing if changing input seal anyway - corrosion under the nuts may mean those bolts are no longer tight hence weep, filler plug is taper thread so has been out and not retightened fully perhaps ? Hopefully means it's had an oil change at least, but low oil is not good for wear rates.
If flanges scored on seal surface then we now have a solution other than replace.

[pierce]

gasket change not a problem, easiest to remove the bellhousing if changing input seal anyway - corrosion under the nuts may mean those bolts are no longer tight hence weep, filler plug is taper thread so has been out and not retightened fully perhaps ? Hopefully means it's had an oil change at least, but low oil is not good for wear rates.
If flanges scored on seal surface then we now have a solution other than replace.

Thanks Aidan, I think you might be right about the corrosion, is this normally a helicoil job to sort out or is there an actual nut hiding somewhere?

good news about the filler plug, I was a bit overly cautious when tightening it, so a nip up should sort that.

Is the flange repair something I would need to take the gearbox to you to fix (if necessary)?

[Aidan]

it's just a case of cleaning off the case and then tightening the bolts a bit extra to crush the corrosion but not much more than the recommended 18ftlb or you'll strip the case then it's timesert time
flange repair is a speedi-sleeve comes with tool for fitting can do them at home

[pierce]

it's just a case of cleaning off the case and then tightening the bolts a bit extra to crush the corrosion but not much more than the recommended 18ftlb or you'll strip the case then it's timesert time
flange repair is a speedi-sleeve comes with tool for fitting can do them at home

Cool cheers for the info