front swivel lubrication

Hi all

does anyone know what the mileage intervals are for checking the front swivel oil on a td5 90?
Cant find any info in handbook or haynes manual,even main dealer could,nt answer
Does it need topping up at all?(filled for life?)and if so ,what lube?.

Thanks for replies
Dave

there filled for life with cv grease ,which entails strippping and cleaning out swivel ,refill with measured sachet of grease ,or if your unsure fill to half way with ep 90 ,you need to use a make shift dipstick ,easier to fill when in full lock as it allows filler hole past the chrome ball