I don't believe the problem is due to the transmission oil type, the company that rebuilt the transmission last year have an extremely good reputation and service many of these transmissions. They have 18 hoists and are known for being the best in the area. I've also had two third party transmission specialists look at it and both state it's not the transmission, but the cooling that is the issue.

 

To me the radiator end type atf oil cooler it is not just cooler. More like heat transferrer. It transfer heat between atf and engine warmed coolant. When radiator is completely hot, the cool end is not cool as air that is passing through the vanes. Then we have an ac condenser that is warm and heats up the air too. When external cooler is placed so that only cool air goes trough it, it will work way more effiecently. Oil in wa580 is not 100'c because of thermostat in the transmission. But because engine heats it up via 95c hot water what goes in to the radiator.
I once installed external oil cooler to 4 speed 90's audi automatic gearbox. Because new radiator was for manual gearbox. Correct radiator was not avaiable. I used radiator about half of the size of what EscapedApe is planning to use. I placed it to the front of the engine radiator so that when the oe radiator fan kicks in it will cool the atf oil too. Granted here is never so hot and we do not have traffic jams as you do have. But car has been working in everyday use now three years in a row.
I would install a thermostat controlled fan to the external radiator. Just because traffic. And place it so it gets coolest air as possible.

 

Here are some pictures of what I did. I had a machinist create the fittings you see based on the end I cut off of an old line. I didn't get a good final picture of the external cooler I used, but it's mounted ahead of the other coolers behind the grill. Nothing is evident unless you look closely, which is how I wanted it. The other pictures show how I routed the lines (kinda). I did not want to cut off the ends, so that's why I went this route. It works beautifully and it doesn't leak.

 

That's nice and tidy, I like it. Just a couple of questions, if you don't mind :-)

• Is the right-angle adaptor for the flow (top) line, rather than attempting to put too much bend into the new coolant hose? I'm assuming the return line didn't need this as it's close to the base of the radiator?
• The Hayden 404 cooler is 3/4" (19mm) thick - do you feel this is the maximum thickness you could fit? I note there is a big jump to the next class, ie. they go from 3/4" to ~2" (50mm).

 

Yes, the right angle adapter was so that the top cooler line could stay within an inch or two of where it used to thread into the radiator. The hose barb points down so that the 3/8" hose runs straight down and loops underneath right beside the bottom hose. I found some silicone tapered plugs (not threaded) that fit in the radiator, and I just kinda threaded them in there a couple turns to act as dust plugs. I always intended to find correct metric plugs, but the silicone plugs fit great so I just left them alone. They've been in there ever since.

As I recall there was a lot of room between the existing radiators and the grill. I wish I'd taken a better picture of the finished product, but as I remember, space was not a concern at all. Should be easy enough to check...open your hood and look down in there, or look through the grill with a flashlight.

 

Aquifer, that engine oil cooler hose is definitely next on your list. Yours is dry rotted at the compression fitting on the left. The thing is I just took my complete EOC assembly off as one of the hoses ruptured. I have a loop installed in place so I can run it just fine for now. I’m going to have mine rebuilt at a local hydraulics shop.

 

One thing I am concerned about, I note your adapters have a long "shank" (not sure of terminology here. I can't find anything like this off the shelf, unless I have a couple of adapters inline, ie. Female M18/1.5 to Male -10AN <-> Female -10AN to 3/8" Barb.



Regarding the space, yes, I should take a peek under my bonnet, however my car isn't with me at the moment, so it's easier to ask :-)

 

The part with your red rectangle is the end I cut off of an old cooler line that I gave to the machinist so he could measure it and create the adapters I wanted. I was not able to find a female adapter off the shelf that would work. If you want to go this route and not cut your existing cooler lines, you’ll probably need to have the adapters custom made.

 

Yes, I've resigned myself to the fact I'll need to get something machined. Do you recall if the adapters you had made had o-rings? I note the bolt heads on the cooler lines are not flat, so they won't sit flush against the adapter.

 

The o ring is on the cooling line itself that you will unscrew from the radiator. The male piece that you circled is what you’ll be unscrewing from the radiator on the car and inserting into the adapter you create. What you have circled is an actual end that I cut off of an old scrap cooling line that I had previously replaced. Your cooling line ends won’t actually be cut off, just unthreaded from the radiator. There needs to be a surface inside the new adapter that the existing o ring will be “smashed” against when you thread it together to keep it from leaking.

You should probably just unscrew the upper line from the radiator on your car and pull it out to get a good look at it. It will become clear what the new female adapter needs to look like. The machinist will need to measure the dimensions of the male end so that he can create the adapter. He’ll need to know the thread size and pitch of the nut, and he’ll cut threads into the new adapter. Basically you’re creating the female mirror version of the male piece that you have circled, with a hose barb on the other side so you can attach a hose for the external cooler.

Since you may not have an old cutoff end to take to the machinist like I did, you’ll probably have to drive there and unscrew the top line from the radiator so he can measure it. Or if you have a micrometer you can measure it yourself and provide him with a drawing of what you need.

 

I didn’t notice that, thank you! The parts diagram seems to show that those lines can be disconnected from the cooler itself. So theoretically, could I remove the hoses and leave the cooler itself on the car? Or is it easier to just take the entire thing off and then take the offending hoses off to be rebuilt? Just thinking about the scope of the project here.

 

Highly advised to remove the entire assembly as one. I tried very briefly to remove the fitting at the EOC itself and it wouldn’t budge. Keep in mind my car is at least 4 years newer than your car and I’ll likely need to put one of the large fasteners on a bench vise. It’s not much trouble to remove the entire EOC assembly at all.

 

Fair enough, that's what I'll plan on doing. Not sure when I'll get to it, I have a 67 VW project that is taking up my shop & lift space at the moment. I'm glad you pointed it out! Definitely needs attention.

 

I miss my first car, a 66’ Karmann Ghia…
😢

 

I had a Volkswagen Rabbit Diesel which was very basic, however it was
also cheap to run and never needed any type of fixing.

 

@aquifer I just noticed this post you made back in 2019, click here, where you found my series/parallel fan fuses issue. Based on subsequent posts/discussions, as it turns out, this wasn't the issue with your shifting problem, but certainly stopped my engine/coolant overheating at the time!

Now, I just have to get on top of this transmission coolant overheating issue!

 

It didn’t end up solving the problem like it seemed to at first, but I did decide that the fan issue is what caused the original overheating problem in the tranny. As a result of the original overheating, I think something in the transmission floated to the cooler and partially blocked one or more of the passages. So even though the fans were fixed it still didn’t cool enough. It’s been a few years now since I added the external cooler, and I haven’t had any issues. So even though I don’t have direct evidence of a blockage, the circumstantial evidence is enough for me!

 

Hi everyone,

Some progress, I hope, I've had another jag mechanic look at the car.

He has verified the transmission oil temperature is not overheating by connecting thermostat sensors to the radiator in/return flow as well as using an infrared gun to check the temperature from the in/return pipes back to the transmission.

His conclusion is that the temperature sender in the conductor plate is faulty. Does anyone know what part number the conductor plate kit is?

The only odd thing is, I've never received a high gearbox temp warning / fault codes even when it hit 120*C / 248*F.

 

Talking to myself here, but found this from Motorcarman, in one of my other threads.

 

Hi can I ask how you managed to do this please as I would like to monitor my transmission temperature as well. Cheers