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[rds]

Hello all

I know this has been asked before but i want to ask it my way!!....and hopefully get views from those who have actually done the full flush with transmission cleaning fluid rather  than just theorising, please.

Popped down to local auto trans garage to get a quote today. After 75k I think the car deserves the job anyway.

The garage would prefer just to drop the sumps and re-fill the amount of trans fluid they drained from there, but as we know that will leave a lot of the old fluid in the torque converter and cooler. I don't really want to do this several times just to get the old stuff out.

They also repeat what i see a lot of people saying on the web regarding full flushes which is that the trans cleaner fluid which they pump through is quite aggressive and will loosen muck/material shed from the bands and cause slipping or blockages when the new fluid goes in.

However, I cannot see what the point of a part-change is.

Also, if you were to just drop the sumps, fill back up and do the same a few more times, I cannot see how will that differ from flushing out the whole lot but without using the transmission cleaner. fluid

So, in relation to this 2.2 with 75k om the clock, all gentle usage with no towing/racing, always in neutral (ie not in-gear against the brake) at standstill, what is the general feeling about the full flush with trans cleaner as opposed to a mere full (or as near as can be done) change of fluid?

Thanks in advance

RDS

[Kevin Wood]

It's worth dropping the sumps anyway so you can clean out the sumps and remove any swarf from the magnet in the sump, and also replace or clean out (with paraffin) the filter.

I'd say at 75k you shouldn't worry about any debris getting flushed out. In any case, that's what the filter's there to catch. Such stories are @rse covering by garages on the whole, IMHO. That said, I'd only flush with clean ATF, not any other agent.

We've always recommended just dropping the sumps and then refilling and checking the level with engine running after a short drive. Yes, there's a litre or two of fluid you can't get to but as long as you haven't left it until it's minging that doesn't really matter.

[Diamond Black Geezer]

I'd second that. The 'box is a 'sealed for life' unit, and only recommends fluid change if a certain number of miles is exceeded in the first year or whatever of driving. That was a looong time ago now! So of course a full fluid change would be the ideal, however at 75k yours is the condition of gearbox many on here would love to get their hands on!

My car's done 209k now, and didn't get it's (partial) fluid change until about 190k, car ran a touch better but wasn't 'bad' even before the change.

Changing the oil at 75k is preventative maintenance, be it full or 'partial'.

[Andy B]

Does selecting neutral instead of leaving drive actually gain anything? I always leave an auto in Drive and had no problems in any car.

[Doctor Gollum]

Presumably it reduces strain on the brake band surfaces 

[Kevin Wood]

Presumably it reduces strain on the brake band surfaces 

All the friction surfaces are fully engaged / disengaged except when changing, so it just means the torque converter isn't heating up the fluid as much (and saves a little fuel).

[Andy B]

Presumably it reduces strain on the brake band surfaces 

All the friction surfaces are fully engaged / disengaged except when changing, so it just means the torque converter isn't heating up the fluid as much (and saves a little fuel).

I'll get 'HOLD'  deleted from my Merc then 

[Doctor Gollum]

That presumably works via the ABS, not the GB

Also, you'll probably find that it unholds after about 30 seconds. If you're stopped longer the parking brake and neutral being more appropriate...

[Diamond Black Geezer]

Ive often wondered this, it 'feels' like you're wearing out something by having your foot on brake, in D, feels 'bad practice', but good to know. 

[biggriffin]

Abridged version.
 Go to BnQ buy fence sprayer.
 Buy some shower gel, chose some clothes you want to throw away.
 Get 9L of Dex3.
 Axle standsx4
Trolley jack,
Various hand tools.
 Old piece of carpet.
Empty 10L drum cut in half Top to bottom
Milk crate.

Jack car up, place axle stands, put carpet under car, putmilk crate under,put drum on milk crate, undo level plug, small amount oilcomes out the nto drum, undo front sump,  whoosh, ,oil in drum and over you, repeat for rear sump,,  then remove filter, clean in parrafin, sumps too, undo cooler pipes, blow thro, reconnect,,  clean and dry parts, smear sumps with goo of choice, refit filter n sumps... Fill spraery with 6-7L oil, put hose into filler hole pump away till it dribbles out, fit level plug,,,, start car,, cycle gears, remove level plug fill again untill drips out.  When you finish, you will see the reason for shower gel and throw away clothes,,, It's easier if you have access to a pit or ramp.

[Andy B]

That presumably works via the ABS, not the GB

It does.....  but leaves the car in gear 

[Andy B]

.....
Also, you'll probably find that it unholds after about 30 seconds. If you're stopped longer the parking brake and neutral being more appropriate...

I'll try it but don't think it does. I know it selects Park if you open the driver's door while being held.

[Doctor Gollum]

Ostensibly there to stop roll back as you engage gear and pull away

Applying Park when the door is opened makes sense as it will stop the car driving off or worse

[Andy B]

Ostensibly there to stop roll back as you engage gear and pull away

.....

That what your left foot is for 
The R Class had hill start assist to do that but it only held the brakes on for 'a short time 

[Andy B]

....
 

Applying Park when the door is opened makes sense as it will stop the car driving off or worse

But .... you can engage Drive with the door opened