final drive / diff bearings

[jimbob-mcgrew]

do these need greasing at all ? or does the gearbox oil take care of everything ?

[millworm]

Should be self contained or gearbox oil mate, no greaseable parts

[mowgli]

they are definitely lubricated by the gear oil. just make sure you get the oil level right, undo the little bung & slowly fill it thru the breather hole on the turret till the oil runs out, then go away for about an hour to give it all chance to settle before putting the bung back in

[jeremy fisher]

What's the reasoning behind leaving it to settle?

[jimbob-mcgrew]

they have a habbit of dribbling for ages after you top them up.

its probably best to let them level themselves off, so the exact amount of oil is in the system, rather than screw the bolt in while its still coming out, and it be over-filled slightly. its not good to over-fill the engine oil, so probably the same sort of deal with the box i woulda thought.

best to do it on flat, level ground too. to get it accurate.

[Stuart]

I just Chuck 2l in and use a pipe and bottle to let it breathe to its happy level lol

[mowgli]

officially from empty is it 1.7L, but from experience of gear oils, that move like treacle when cold, it takes ages to get the level right.

[jeremy fisher]

Noted. Now who can tell me why my diff no longer seems to fit in its housing!!!

[phunkynova]

How long is a piece of string ? sorry I'm not being negative but your question is a bit vague.
I trust it is the same diff that came out of that gear box and that you are putting it back in the right way around and that one of the wind-in diff bearings is removed from the gearbox ?.

[jeremy fisher]

It was a bit vague yes. I wasn't really expecting a proper answer, more a slight venting of frustration. But as you asked. It is a quaife diff, with new bearings going into a different f13 casing to previous, but it should be the same. The big castleated nut is completely removed but it seems to be a few mm short of getting into the casing. I also rebuilt the diff, but i don't think i made it bigger!

[mowgli]

i'm sure i've read somewhere that some of the aftermarket diffs need some metal grinding out of the diff housing, but don't take that as being a 100% definite answer..
have you compared it to a gm diff to see if it is dimensionally ok?

[Stuart]

yes, you need to grind some out of the diff housing.

[jeremy fisher]

Well I remember the first time I fitted it, it was a bit of a squeeze but managed to get it in. It almost seems as if the bearings were sitting slightly more proud this time. I took a die grinder to it last night. Wish I'd realised before refitting the cluster!
Am I right in thinking that the large castleated nut needs tightening until there is no play in the diff then backing off slightly to allow for heat expansion?
Thanks.

[Stuart]

yes, you set it like the rear wheel bearings.
tighten till its nearly impossible to turn the diff by hand, then back off till it turns with easy (but not freewheeling)

[jeremy fisher]

Thanks, thought so.
Back to Mowgli's previous comment, I did sit the diff I'd removed from the housing along side the Quaife item and sat a straight edge across to check size. There was some minor concern that the casing hadn't closed up properly after I rebuilt it, but all was well.

[phunkynova]

You need to grind the housing out if you look on my build thread there are photos of where I have modded the housing.

http://www.pngclub.com/forum/showthread.php?147449-Czech-it-out-Nova-Rallyx/page3

If you look close you can see where I have ground out the housing.

[jeremy fisher]

Thanks, that's pretty much what I ended up doing.
Though I'm sure I didn't do it the first rime I fitted it??