Thread: Backlash issue - Sals diff

Because crownwheel backlash, as well as bearing preload in a sals is set by shims at assembly, the only way to develop excessive backlash (assuming proper setup to begin with) is excessive wear. Or perhaps the pinion crush tube has crushed? Surely by then it'd have to howl like a banshee. Interested to know what's going on inside there.

Righto, finally had a Saturday free with fair enough weather to bear laying on the concrete for a few hours.

Removed the plate and had a look.

At this point any particular tests that would yield information would be helpful

I couldn't figure a way to lock the pinion up 100% but the crown wheel, dial gauge horizontal at the exterior of the wheel had .48mm of backlash.

placing the dial gauge on the horizontal plane against the crown wheel and using a pry bar to move the diff itself yielded .22mm of play - however i'm not sure I did this test correctly.

There is some minor putting and rust on a couple of the outer edges of the coast side of the pinion.

I have put the ARB install off for the moment. Might be looking at a new whole axle yet!

There is water in the oil - however the recent trip saw the vehicle sitting in water for 5 minutes or so that was over the bonnet so that could attribute to it - obviously the breather is something I need to look into soon but the diff comes first.

Lock the crownwheel from rotating by using a small wedge of wood etc to jam it against the case. With the handbrake off, check how much rotation you get on the input flange, and compare to when the crownwheel is free to rotate. Since you have already checked drive splines etc prevoiusly and not found any play this will give you an idea of how much if your play is in the spider gears and how much in the crownwheel/pinion backlash.
There shouldn't be any lateral play in the crownwheel - there should be some preload in the bearings. From memory the manual says to set it up initially with clearance, measure how much and then add a specified amount to get preload. The total is total thickness of shims to add.

Steve