automatic gearbox problems

[Timberwolf]

There's one thing I've noticed that links most makes and models with forums full of "autobox dead" topics - and that's the ominous phrase sealed for life.

My opinion is the concept cannot exist with current technology. It's a testament to how good the modern autobox is that some of them are surviving 100k+ miles with no servicing, but realistically the manufacturers asking the customer to fork over £100+ to have the fluid changed at every 30k service are doing the right thing.

The problem I see with the AW55 series is that its behaviour on knackered fluid (disengage drive and then *slam* the gear) lunches the 'box on short order, combined with features like slipping lock-up and '01 cars' stop-neutral that make the fluid work that much harder.

Of the boxes that are dying around ~50k miles, I wonder how much of their life has been spent in situations like towns and traffic which would cause the fluid to get very hot? Mine has as far as I can tell seen quite a bit of urban use over its 60k and the autobox is a "could be better" - I've had a fluid change and that improved things a lot but I still don't have total confidence in the thing.

It's a shame as when they're on form I think they're great autoboxes - a little more TLC in the service schedules would mean they stay great autoboxes past 50k, 100k, 150... rather than dying early. Suppose it's one of those industry-wide problems where manufacturers are trying to extend service intervals and keep service costs down, and sometimes they push just a little more aggressively than the hardware can handle...

[jackass]

Originally Posted by Bernard333

I was hoping to get pearls of wisdom relating to the AW55-50SN which are fitted to the Volvo but not one of the posts on this BMW thread mentioned which gearbox they were talking about although I am told it is the same gearbox ?

AW55 box is for transverse FWD/AWD applications, so it won't be used by BMW or Merc who both use longitudinal (predominantly) RWD configurations; I wouldn't rule out them using Aisin Warner 'boxes just not the Volvo one.

AW55 is used by Saab and Vauxhall and presumably Toyota.

Originally Posted by Timberwolf

It's a shame as when they're on form I think they're great autoboxes - a little more TLC in the service schedules would mean they stay great autoboxes past 50k, 100k, 150... rather than dying early. Suppose it's one of those industry-wide problems where manufacturers are trying to extend service intervals and keep service costs down, and sometimes they push just a little more aggressively than the hardware can handle...

Volvo service schedule does specifiy an oil change at 80K for cars used as minicabs / for towing. Although mine was definitely in need of it long before that (was missing shifts since I bought it at 60K, although almost exclusively after high speed right handers - which I presumed was more oil surge that old oil). Has been behaving much better since I got the oil changed at 84K miles.

[Rover Saloon]

I just glanced through this string and can't weigh up what I am reading against my own experience. I have a 2000 S80 2.4 170bhp auto with the AW55-50SN box. I have currently done 142k since new much of it towing a heavy caravan across Europe. The box has never given a hint of trouble and, as yet, I have not changed the fluid. I was interested in the thread because I am about to do that - it's a bit brown but not that smelly. So why has my box gone 3x as far as some of these others? It can't be down to luck surely in a world of very high manufacturing accuracy and tolerences. Is it the way some cars are driven?

[Talon]

Is changing the fluid in the autobox like changing the oil? Can anyone do it by pooping the car on ramps or is it a dealer Jobby

[Symes]

Talon, if you search the forum for 'gearbox flush' (or similar) then you'll find some great info about how to 'properly' flush the box!

Rover Saloon, I agree with you - my previous V70 (170) had 168K on the clock and with the exception of occasional N->D clunk was really smooth, and given a few days standing it would be perfect to the extent of being 'like new', so it was probably a slightly low level which was noticable when the oil got hot and was circulated.
My current geartronic is near 150K and also fine, however I will be flushing the box as a precaution (and in an attempt to get it to shift up faster from a standing start).

I presume that, just as an engine - if the car has done a lot of motorway miles and few 'racing starts' the components will be in better condition than lots of short, slow journeys.

[Blue Oval]

The reason that Merc forums are overwhelmed with autobox faults is because nearly all Mercs are autos! Stands to reason they will proportionally have a lot of autobox failures, they don't do manuals in anything much other than A-Class!

[prm36]

Symes, have you not changed your fluid previously?

[Symes]

prm36, not on this one - I've only had it for a few short months.... it was dealer serviced until just before me but I doubt that the transmission fluid has even been looked at!

I changed to a diesel to save my wallet... I now only fill up every couple of weeks.

Now I think about it there's a box of vauxhall sourced, 1l bottles of oil in the back of the freelander! (another story allthogether!).

The fluid in my D5 is a reasonable colour, brownish on the dipsick with a tinge of red when wiped on a (paper) towel - so it's probably not that bad. Tends to suggest that my motor has spent a lot of time in 'top' gear rather than changing every couple of minutes around town - so maybe that's why it's OK.

[prm36]

Originally Posted by Symes

prm36, not on this one - I've only had it for a few short months.... it was dealer serviced until just before me but I doubt that the transmission fluid has even been looked at!

I changed to a diesel to save my wallet... I now only fill up every couple of weeks.

Now I think about it there's a box of vauxhall sourced, 1l bottles of oil in the back of the freelander! (another story allthogether!).

The fluid in my D5 is a reasonable colour, brownish on the dipsick with a tinge of red when wiped on a (paper) towel - so it's probably not that bad. Tends to suggest that my motor has spent a lot of time in 'top' gear rather than changing every couple of minutes around town - so maybe that's why it's OK.

Exactly the same as mine at 72k, was thinking of changing it hen i get the cambelt done around 80k or should i leave well alone?

[cjr]

ntrigued to know whether changing your auto transmission fluid prolonged the life of the car. My S80 has a clunky down shift 2 to 1st, and some times around town the revs increase without a gear change or acceleration.

Cheers