Strengthening the automatic transmission on the cheap

Any ideas how long, if working non stop, would it take to complete this fix from start to drive away?

You planning on giving it a go yourself Trevor, or paying someone to do it?

Can someone please upload a close up photo of the area circled below on the rear cover? Is it supposed to have a bolt head in the end where the arrow points to? Mine has like a blanked off pin or something in there.

EDIT: it's normal.

YAY!!!!

I got it all back together! Well, the cover is sitting on but I'm waiting on some o-rings from Mitsubishi still before I can seal it up. Grrrrrr.

Kenneth - Could you please post up what you PM'd me about those bolts not to undo on the valve body, and the warning about the ball bearings. Pics would be really helpful.

Nathan - Any tips for avoiding tearing the valve body gasket?

So the valve body cover has to come off to do this fix? Sounds like it was the hardest part.

I took the valve body cover off only to look for bits of the broken wave spring. I didn't actually remove the valve body myself, like the others did. I've managed to install the seal through the input shaft side, but it's a real pain in the butt. Too much chance of making a mistake. Seriously, do yourself a favour and take off the valve body and insert the seal through there after you've put the rest of the box back together.

You'll need to remove the radiator, the intercooler hard piping on the cold side, and the battery tray. I stuffed about, but if I knew to just get on with the job and remove that stuff first it would have much quicker and a heck of a lot easier.

The valve cover will then easily come off and you'll have plenty of room to stick your head in and have a look, instead of playing with mirrors like I did. Remove the valve body, insert the new seal, and reassemble.

I reckon if you allowed a day you'd do it easily. Originally I said about 5 hours, but doing it via the valve body side allow another 3 hours. I've taken hundreds of photos and been writing notes along the way. I've also taken the time to try to learn what everything does along the way, and try different ways of fitting components back in so as to make some recommendations in the write up.

Order all your parts in advance, some will need to be back ordered. That's another reason I've taken so long. I've been waiting for parts to come in, so I haven't been in any hurry and have been fiddling about a lot.

I will make a suggestion here - if you are thinking of flushing your ATF or adding a transmission cooler, and you reckon you are competent enough to do the wave spring fix, I seriously recommend you do the fix before you do those other things. My transmission has had a cooler fitted since I got the car, the ATF has been flushed using SPIII and the car has been driving absolutely fine.. but I still found a broken wave spring lurking inside. Although adding a cooler is not a bad idea at all, I think it's going to give you a false sense of security.

It is not a long job but waiting around on parts. Its no race so your better to take longer and make sure it is right. the valve body gasket on mine ripped when i removed the valve body. these normally are fine and you can refit the valve body without having to buy a new one.
The biggest tip is to check and double check everything, make sure you have the right clutches going in the right way and also look for wear signs on the metal to double check you are correct. I myself did not remove my battery or tray but it may help you to get more room.

Nathan is probably right, if you think you have enough room you can leave the battery tray in. I remember I initially took it out when I was looking for lever points for the transmission rear cover. But if you have taken out the radiator and intercooler pipe then you should have plenty of room to work.

I only took the radiator fan off, but I reckon it would have been easier to just remove the whole radiator. I actually drained out a bit of coolant too, because I disconnected the top hose from the radiator to bend it out the way.

If you want to remove the battery tray, after taking out the battery there are 3 bolts in the bottom of the tray and an arm that attaches to the airbox. There's a small nut, 10mm I think, inside the front of the airbox you need to remove. Then after that there's a L shaped bracket under the battery tray which has another 2 bolts holding it.

Some good news regarding the smaller o-rings, it turns out that they are a standard Japanese size: 9.8mm ID x 1.9mm C/S

I now have a source for the o-rings, picked up a couple of dozen on the way home from work and they fit perfectly. As I figured, they are a Japanese sizing and only specialist shops will have them. Not a huge cost saving, but better availability than from Mitsubishi. The genuine ones I bought were the last three in the country and any more had to be back ordered from Japan.

Nitrile (Buna-N) 70 Durois fine for the o-ring material, it's rated for transmission fluid and temperatures from -40ºC to 120ºC. The transmission fluid's normal operating temperature is 70ºC to 80ºC.

So, I'll probably offer my set of six genuine Mitsubishi o-rings up for sale here when the remaining ones finally come in. Anyone interested?

This one had me a bit stumped, but much measuring with the calipers indicates that the larger o-ring seal MD756673 on the clutch accumulator should be: 37.7mm ID x 3.5mm C/S

That also happens to be a standard Japanese size. The reason I couldn't figure it out is that ASA/CAPS is giving some misleading data that I don't believe can be correct.

I do have a new genuine seal on order and will check that out when it arrives, but I'm also going to purchase some aftermarket ones tomorrow as per my above measurements and check them for suitability.

Guest said:

I now have a source for the o-rings, picked up a couple of dozen on the way home from work and they fit perfectly. As I figured, they are a Japanese sizing and only specialist shops will have them. Not a huge cost saving, but better availability than from Mitsubishi. The genuine ones I bought were the last three in the country and any more had to be back ordered from Japan.
Nitrile (Buna-N) 70 Duro is fine for the o-ring material, it's rated for transmission fluid and temperatures from -40ºC to 120ºC. The transmission fluid's normal operating temperature is 70ºC to 80ºC.

So, I'll probably offer my set of six genuine Mitsubishi o-rings up for sale here when the remaining ones finally come in. Anyone interested?

Click to expand...

PM sent.

Here's the o-rings that I'm talking about.

I can give a part number later for the valve body gasket. I got her fired up and running today. don't notice any real difference although the trans was over due auto oil so it is a little smoother changing gear

interesting with those o-rings. i ordered the genuine seals but at work we have a metric box that has common sizes, i think it cums from wurth. i was able to match up the large o ring as well as the single small o-ring i was missing and the proof is that the cars going. so even if there was a slight difference it is not going to matter.
by the way i fitted my seal that we have had much debate over at that angle and had no problems.

Glad that you managed to find a good match. The problems inexperienced people could face with an improper o-ring selection are the o-ring falling or slipping unnoticed during installation, pinching from the cover or not sealing properly.

Which angle do you mean for the seal? Like the factory install in the pic below?

Yes i did the same as above. Hows your trans coming along? it will be interesting to see what difference you notice between the broken spring and the new one.

I ended up putting my 2nd brake seal in the same way as the pic above too.

I've got all the o-rings so all I have to do now is put the cover back on. First, I'm going outside now with a compressor driven suction gun to bleed all the fluid out of the transmission's cooling system.

ATF has also continually come out of the transmission over the last week, I wonder if there could be really much more still held in the galleries. Did you find much run out when you removed the valve body?

I'll probably end up doing a flush sometime this weekend still, just to get any undesirable material out that may have snuck in there.. but I've been really careful and had it covered when not working on it.

How long did you leave your liquid gasket cure for before filling & driving?

I got around 7 lt out of my box while it was sitting. There will probably be another lt in the torque converter as well. I just left it over night. and there are no signs of leaks. it sets fairly rapid.