Leaking Rear Diff.

[Calster17]

I managed to get a good look under my 400 today, and thankfully everything seems to be fine, other than the rear differential.

Around the front it's leaking, not constantly, but the front of the differential is damp. It look's like it's leaking from around the propshaft. I'd guess and say it's just needing a new seal. Haven't checked the level yet, but haven't experienced anything different while driving, everything feels smooth.

Is it a common problem? And has anyone here done it them self, and if so is it easy enough to do at home? (or best to have a ramp or need to remove the diff?)

Thanks in advance guys, i'll post pictures later when I can get photos off my phone.

[ambermarine]

Callum

On the early marques of the LS400 there is an expansion valve on the top of the diff this allows any pressure that builds up in the diff to escape. The hypiod oil in the diff is a very heavy viscosity and if heat is produced through heavy loading the pressure as to be allowed to escape,it may be this is the cause of your dampness .Check for leakage in fluid form by cleaning the diff off and checking for drips at the bottom over a period of a week.

[steve2006]

Another good suggestion from ambermarine, I'll just add to by saying get some gunk type stuff and clean all the accumulated oil off completely then monitor the leak. Talcum powder is a good way of pinpointing any leak as it is easy to see the path with it being white.

From the looks of the service manual the oil seal can be replaced by removing the propshaft and the connection flange on the differential then getting the seal out although a SST ( Special Service Tool) is mentioned as being required to remove it but improvisation is probably the way forward i.e some hook device to pull it out and a suitable drift to refit.

If you would like a copy of the service manual covering the proceedure just pm me an email address.

[Calster17]

I'll hopefully get a chance to give it a good clean in the weekend. Here's hoping it's just the valve.

Here's the pictures I managed to get...

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Seeing the second picture, it does look like it's coming from the top. But I'll check everything properly asap!

Thanks!