Sierra LSD misting.

[CPGCharlie]

Hi all, 

My 7 has had a misting on diff advisory on the MOT and I've taken to a 7 specialist who have now said it's leaking badly and needs rebuilding, Diff out 10 hours work etc. The advisory was to simply change the washer in the Diff.

unsure what to do and how coincidental it is that as it's turned up specialists it needs an immediate expensive repair. 

what can i check for to assess?

Best

[SM25T]

You can remove a diff on your own in your garage in an hour ... I use a trolley jack to support it.

If it is a drive shaft seal leaking, you can replace this in no time by just removing the drive shaft complete with deDion ear ... it just pulls out. Had to replace one when staying at a ski chalet at 8000 feet in the Pyrenees ... with no access to any special tools.

[SM25T]

If it really needs an overhaul, then you should send or take it to a transmission specialist .... locally here we have Road & Race Transmissions, near Sevenoaks.

[CPGCharlie]

Many thanks, Ian - great to know.

any direction on where to look for parts, I wasn't given any details about the Diff when I bought the car so any way of deciphering exactly which Diff it is would be great? 

Will speak to Road and Race also

[Dan sigma 140]

I'm not sure where you are based, but I recently had my titan diff rebuilt. I took the car to NJ Potter, who removed it and sent it to RR for the rebuild, NJ Potter then fitted it back into the car. All in it cost less than £700. I think though this depends what diff you have and how bad it is. 

[ScottR400D]

I think an hour to remove is a tad optimistic but I can certainly remove a diff in 2 hours and refit at a careful pace in 2.5 to 3 hours. 

Doesn't the Sierra diff have a breather? Could that be the source of the misting?

The first thing I'd do is clean it all off, make sure the level is right, then run for a while and try to determine where and how bad the leak is. 

[simon_h]

I'd clean it all up. Check the breather has a bit of tube going up and looped out of the way or even to a little catch tank. Check the level is about right. Then take it for a good drive to get everything nice and hot and see what it looks like.

As said it's not that bad a job, although not much fun, removing and refitting the diff. 10 hours labour seems a bit excessive though. 

[Tazio]

10 hours is taking the mick. Wrightpayne and I have recently pulled mine, there are time and money saving methods that a 7 specialist should know. For example. you don't need to disassemble the hubs,  these can be removed complete with the driveshafts, all you need to do is detach the calipers, tuck them out the way, undo the hub carrier bolts from the ear, and pull the driveshaft out complete with hubs, ( don't just pull from one end of the driveshaft, pull the hub, and use the other hand to ease the shaft out of the diff, keeps the CVs together).

Alan