Diif to Propshaft freeplay

[Kevin]

Just a query from a mate who has just replaced his propshaft UJ`s and noticed on completion that he could turn the prop a good 90% before the slack was taken up at the diff end, now do you think that this is due to wear (its done 170,000) and although its still quite it has been suffering a little from juddering in reverse which has reduced due ti the new UJ`s.
Or is that an acceptable amount of slack ?

[rayofleamington]

When it's got 360° of freeplay - then it's definately not ok ;-)

All cars will have some as the diff is not designed to be free of backlash but as to the actual amount where it is deemed 'not ok' is not something I'm aware of.
Certainly 90° is a LOT and does not help with things like reverse judder or axle tramp as it allows more wind-up travel but as long as the diff oil is not heavily metallic and the diff is not too loud, I'd be tempted to leave it like that - I've never had a diff actually break (using standard Minor engines) even if they had a lot of rotary free play so it isn't neccessarily a sign of imminent failure.
If it's a very high mileage car (e.g. 20,000 miles per year), it would be adviseable to keep an eye out for a spare diff.

[bmcecosse]

Sounds a bit too much - some of it will be half-shaft splines. Start collecting diff + half-shafts NOW!

[Willie]

Does seem a little excessive and is most likely due to wear in the planet
wheel washers which can allow a huge amount of movement which translates
into lost motion. If he notices a metallic clunk on odd occasions when the
rear axle goes over a bump then it is almost certainly worn planet wheels.
If he fancies the job he could buy a new set of these special washers and
fit them which usually restores to almost as good as new conditions.

[Kevin]

Thanks for the replies I wil pass them on at our next meeting.