A funny thing happened on the way to Dunblane!

[Smarty2]

On my way to Dunblane from brum this morning and my AL4 cruddy box felt like going into limp mode from 70! Three times! Found an ags place in Preston so had to do a uie from Kendal for an emergency fluid change! fortunately they could fit me in, but the technician said I need a new valve body and he had one in stock and could fit it in a couple of hours for 495 quid all in, seemed reasonable to me so we are enjoying Preston town centre! seemed a cheaper alternative to a recondition! He told me he has a steady stream of dp0/al4's at least on a monthly basis! heres hoping?

[Smarty2]

Well, we arrived, gearbox is a million times better now, the technician showed me the old valve block, and his technical term to describe it was "minging"! Do you think I should give it another fluid change when I get back?

[Ben82]

Best thing to do is ask how much LT71141 they used. If they used ~5l then it's most likely worth doing more changes, if they used >15l then you should be fine

But of course you might not want to take their word for it, and try checking the oil yourself or just doing another change to see the quality of what comes out.

[Smarty2]

I asked how much fluid and he said there is 9 litres in the al4? so in that respect he did a complete change. he showed me the oil too and it was in a terrible state, black with grey sludge! so that's a recommend from me if anyone lives in the Preston location.

[Mandrake]

It's impossible to do a "complete change" of oil as such, as about half the oil sits in the torque converter and can't be drained out, at least not without totally removing and stripping down the gearbox, which I doubt was done here...

To get the oil cleaner than the 50% that one change would give the only options are multiple changes with enough time for the oil to mix between changes, (two changes effectively replacing 75% of the oil) or a hot flush where a drum of new oil is connected to the heat exchanger line to be sucked in while the other line is drained into a container...Then you let the pump in the gearbox pump the old oil out for you (including oil from the torque converter) while it sucks in new oil... I would think it would take more than 9 litres to do that thoroughly though due to inevitable mixing between old and new oil...

[Smarty2]

Better get it changed then.