reverse piston replacement
 

after doing lots of research about the replacement, i decided to buy a car with a known reverse piston failure with the hope that it can be repaired.

this is how mine came apart

battery off and fbh out of the way (that makes it a bit akward)

http://i922.photobucket.com/albums/a...ps62edbf0d.jpg

wheel arch out of the way

http://i922.photobucket.com/albums/a...ps5663ac65.jpg

bolts out of casing

http://i922.photobucket.com/albums/a...ps80188d52.jpg

cover off (probably the most difficult part, the cover has to be manouvered in a certain way to get it out)

http://i922.photobucket.com/albums/a...psb28e6385.jpg

assembly out

http://i922.photobucket.com/albums/a...ps2f487517.jpg

http://i922.photobucket.com/albums/a...psd5346014.jpg

assembly stripped

http://i922.photobucket.com/albums/a...psd167d994.jpg

for those who have seen the how to and bienet1's thread, they both had to take extra bits out, where as with mine only the part which needed to come out actually did. so bienet1 was correct when he said the two parts he seperated first should just come appart.

the reverse piston is definitly cracked, i dont have a pic but its cracked about a third the way around. the good think is there wasnt much sludge on the rpm sensor and very little on the drain plug so the 250 mile journey home didnt do it any harm. the clutch plates all look in good condition so hopefully they wont need replacing. the o rings seemed tired but were complete. and the oil was dark but seemed clean.

took me about an hour an half to strip so not to bad. just need to order another piston, o ring set and oil and hopefully it will be running soon :)

Top man there Reece, Keep us up to speed :)

Hi RRobson,

Glad to see that my work and research is usefull for someone :)
I love to see those pics :)
Keep up the good work and keep us updated about your progress. I would recommend to replace the circlips to just in case, they are not expensive.

Lovely job Reece and excellent photographs. Aren't automatic gearboxes works of art? :D

Simon

Lovely photos there, accurate and sharp. What it is to be able to do your own repairs.

Yes, your thread was especially useful.
Thanks for the circlip advice, will do that.
It makes more sense now I've done it myself. I was unsure what you meant when you said about compressing the spring with a wooden washer and clamps but obviously I now know.
Nothing was worn as bad as yours. The o rings aren't doing anything though, there's probably only a few thou compression on them.

One thing I noticed is the piston is its a lot smaller in real life, for those that can't judge, the spanner in the pic is 12mm so quite small.

Will get some more pics when there's light. All the clutch plates have still got the wear marks on them so there's plenty of meat left

Yep; worth noting by those who say that automatic transmissions have to be 'rebuilt' at massive expense! :)

Simon

Yes, they are stunning pieces of kit, but it would appear not as complicated as we are lead to believe? Even looking as the exploded diagram on that PDF file, there isn't that much to them really. Obviously they are complex, but they certainly aren't a dark art or require magic to service. If it was separate of the car I think it would be reasonably simple to completely strip and overhaul. Such a shame gearbox removal is quite labour intensive.

One thing I learnt about these gearboxes is that they are fitted to a number of cars. From memory they are

Ford mondeo
Ford galaxy
Vw sharan
Seat alhambra
Mazda mpv (not sure which this is)
Jaguar x type
Land rover freelander

So this would explain why the oil on bienet1's thread had so many specs which it met.

I will get measurements, but they look bearly worn and the gearbox has covered 160k, so it shows how robust they are

It's the Mazda 6 I believe.
Indeed. My SD1 has covered 170,000 and the only replacement part that the GM automatic gearbox has had is an externally mounted vacuum modulator. So despite their complexity I'd say that they're just as durable as a manual box.

Simon