How much oil can a transfer box lose before it causes a problem

Webley1991 · Dec 8, 2018

The transfer box on my series three has always leaked a bit around the poorly designed tin plate bottom cover.

Apparently it is near impossible to get these to seal fully unless one of the cast aluminium replacements is used.

As those are £60 or more each, I have been simply topping it up, especially as I have 16 litres of 80w-90 GL4 oil that I got for free. In the end I cut a rubber gasket for the square inspection plate on the top of the box. Now I can simply remove the plate and check the level or add oil from the top.

This made me wonder how low the oil level can drop before it would cause a problem?

jamesmartin · Dec 8, 2018

if you get all the surfaces clean and use a little silicone sealant either side of the gasket you can get a good seal,. you can lose quite a bit maybe 2/3rds since low gear box sump is on a slope and low gear runs quite close to the sump , on long journeys heat would become an issue

steve2286w · Dec 8, 2018

Ive been working on the various leaks in last few months with leaks being a failure in the MOT changes earlier this year, Stopped mine leaking as James said using some LOCTITE SI5980 black silicone, I nipped up but then left till next day to give a final tweak, I have the original tin one fitted, I did check for flatness on it with steel rule and needed to bend at least one of the corners to bring it back flat, a better way would be some flat glass and engineers blue compound

tottot · Dec 8, 2018

Had a mate turn up with his transferbox screeching, it was empty of oil !
Fitted new gasket and filled it up. Worked fine for many more years.
At work and play I have bust just about every thing you can on a series but not a transferbox.

Webley1991 · Dec 9, 2018

Thanks for the replies.

I was advised on this forum not to bother with the bottom plate seal as it would most likely leak again.

steve2286w · Dec 9, 2018

That’s one persons experience, With care I don’t see why it should leak if done properly, what worked for me, ensure plate is flat all over , both faces cleaned and degreased, good quality gasket, sealant on gasket, fit gasket, sealant on plate, follow the tightening procedure from middle out and not too tight, I think I did this initially and distorted plate , in the end got sick of the drips and got it sorted been a few months now and bone dry

Bobsticle · Dec 11, 2018

Well you learn something every day.

How long have they needed oil in them

rob1miles · Dec 12, 2018

I cleaned mine, new gasket, got the cover as flat as possible and losts of gasket seal and it drips one or two over night which I can live with. The leak I thought was from the plat was actually the rear shaft seal.

How much oil can a transfer box lose before it causes a problem

Webley1991

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jamesmartin

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steve2286w

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tottot

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Webley1991

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steve2286w

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Bobsticle

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rob1miles

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