Transmission Cooler - Flushing

[dave_aber]

Hi all,

I'm in the middle of changing my ATF, and decided whilst the sump was off to try to blow through the oil cooler section of the rad to get as much old fluid oout as possible.

With both pipes disconnected at the transmission end, I can't blow them in either direction to get fluid out.

To my mind this seems like the cooler may be blocked. (I'm assuming that the pump is inside the transmission, so out of circuit now I've got the pipes off) Or is it just me being too breathless to blow through the pipes?

I'm considering getting the compressor out, but I don't want to damage anything.

If it is blocked, it's been runing like that for a while with no problem.

Any advice ?

[missfixit70]

Low pressure on the compressor should be ok, if it is blocked I'd get it cleared through personally, you can always disconnect at the cooler end, blow those pipes through individually & the cooler. On the few I've done, I could only just blow through the 2 lengths of pipe & cooler manually & ended up pretty red faced, much easier to do them seperately, means you're getting a bit more of the crappy old stuff out too, the more the better. I also blow through the connections into the 'box.
Dunnings Autos suggested a couple of turns of the engine on the ignition would empty a bit more out of the torque converter gubbins, but with a big "on your head be it if you let it turn over too long with no oil in the 'box. I did try it & it got a bit more out, think I got nearly 7 litres out of that one.

[dave_aber]

Good call Kirsty, I'll have a rake about and find the front ends of the pipes.

I did just run the engin for 30 seconds or so, and got a wee bit out - just spits and drips though.

Cheers
Dave

[dave_aber]

Another quick question - I've got a breather hose hanging down the side of the box - should this not be clipped on somewhere high up, with the open end pointing down? Mine is hanging down in a "J" shape, with the open end pointing up.

[missfixit70]

Think so, look at X on here - http://www.lushprojects.com/bongopartsm ... 1of03.html

[Northern Bongolow]

i used a styrup bike pump on mine,with an adapter for blowing up air beds etc. dont use too much pressure as the cooler ismade of thin copper/brass like material.
the raised vent does clip high up on what would be the bellhousing in a little clip,these usually dissapear,just cable tie it high up on a cool bit.

[dave_aber]

Thanks for the replies - a wee push from the compressor on low pressure got it moving.

A word of warning though. No matter how sure you are which direction the pipes are pointing, don't trust them when you put the air on! I now know intimately what the ATF looks, feels, smells and tastes like.

It did seem to belch a blob of sludge through first, then ran free, so maybe I've freed up an almost blocked cooler, which can only be a good thing.

I found part of the clip on the bodywork which should hold the breather - tywrapped to a cable loom now.

And a quick test-drive confirms what many have reported - although the old fluid looked OK, the changes are noticeably smoother now, and that's cold just going round the block.

[Alacrity]

A lot of garages just blow through the cooler lines with compressed air to clean them out. It doesn't. However it doesn't normally cause any problems. We use a bit of kit from the USA called a Pulsator to clean the cooler & lines out, its purpose designed to clean out coolers & lines using a solvent mixed with pulsating air. Still if we have a vehicle with a major mechanical failure the only way forward is a new cooler - or pipe out the old one & replace it with an air/oil cooler.

[dave_aber]

I appreciate that blowing out the cooler will leave all sorts of gunk behind in the wee passageways, but it's better than nothing. I was surprised how hard I had to blow to still not move anything. There was a definate 'burp' of crud when I put the air on though, so if I have shifted a big dollop of sludge which would otherwise restricted the flow thourgh the cooler it's in a better state than when I started.

I di consider trying to draw petrol through the cooler using the Pela, but I dodn't want to risk having a cooler's worth of petrol ending up in the transmission - that can't be good for it!

[missfixit70]

Good result Dave, as has been said before, worth doing it again at some point in the future (not too distant). Same as with anything, you're never gona get all the crap out in one go, let the new oil flush round & get things flowing a bit better. I think I've said it before, but I reckon a lot will be driving around with blocked/partially obstructed coolers.
I wonder how many gearbox issues would be prevented by regular oil changes? Especially when so many people seem to think they are "sealed units" Reckon I may be doing mine again soon.

[mikexgough]

some pics here http://www.geocities.jp/aburamn/fure.rajietakoukan.htm shows you what is inside.... scroll down to around 2/3 of the page........

[Alacrity]

I only meant we would use the flusher when changing the transmission, not when we are just changing the oil. However your experience Dave makes me wonder . . .