Hi Niall
To flush or not to flush, that is the question.
Flushes are not all the same and neither are all the fully synth oils.
Its only when you read about them you discover that they contain a lot of different ingredients.
What percisly all these ingredients do i dont know.
I used the Amsoil flush and (well) every thing seems to be fine.
If you dont use the flush for what every reason the synth oil will clean the engine just the same but over a longer period.
Using a flush will remove more build up quicker than if you dont flush.
But how much build up is there in the first place in the engine no one would know.
It depends on a lot of factors such as mileage, service intervals, oil used, driving style, proper and prompt maintanance of problems.
It is a rare accurance that an oil port will get blocked by purging the engine but you need to decide based on what you know.
Its also worth thinking about seals and if they may leak or not and again it seems to be one of those things that you really dont know.
I plan to hopfully change the AT oil the Diffs and transfere box to Amsoil aswell soon.
I would love to be able to change all the AT but it seems this is out of my limitied ability, so ill have to settle for about 50/50.
cheers
john 92HDJ 80 1HDT