Monday, Jun 27, 2005 at 21:10
You're right - others may disagree :)
Have only just done 10,000 km in my auto petrol LC100, and still working out how the gearbox operates. It appears that the lock-up clutch (sometimes mistakenly called overdrive) activates in 3rd as
well as 4th, but not 2nd and 1st and disengages down
hill (I think).
I agree that it is good to use the power button - but for a different reason: it delays the changes points, keeps the revs in the torque curve and thus engages the lock-up sooner after the change-up. This means that the torque converter is not slipping and converting power from the engine to heat - this convertor slippage is what heats the box - if it is healthy (unhealthy boxes, with slippage from the bands and clutches will burn the oil very quickly - gearbox temps may not go up in this case as it is oil between the band and drum, or between the clutch plates that burn. Sniff the oil off the dipstick when you check it - if it smells like
well BBQ-ed bacon (true!) get it serviced urgently).
Getting the lockup engaged is what saves the box from overheating - this is why some auto box vendors/reari centres sell a seperate switch to manually lock up the converter. Much better for towing.
Sand driving can be a killer - towing through sand can terminally overheat the box. If you are thinking of doing lots of that, invest in a gearbox temp guage. Be wary of temps above 120º and if you go above 150º, flat top the car back to the service centre (I kid you not - the tow truck will be cheaper than the repair bill if you keep going...)
i service my auto boxes every 20,000 km or one year. I do not use fancy oils - just Dextron II or III (my auto man will not warranty his boxes if synthetic oils are used - and after having done 160,000 with one of his autos with a 260 kw/580 nm motor in front I'll take his word for it thanks :) Synthetics are too slippery and promote slippage and thus burning in the bands/clutches - though I have to say that guy in
Melbourne does use them in his boxes. Wonder how he gets away with it...
Have a read of this link - I find the guy pretty good, but do disagree (at this stage, until I get more info) with his choice of oils for the auto:
this link
Th following is the guy who I use in
Sydney and he did a superb job on a sadly misused auto box in my Cruiser. I have used the workshop associated with him (Vince) since 1996 - it is said he is arguably one of the best auto guys in Oz - just a personal endorsement - I don't get any discounts :(
Powershift
/viz
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