360 Transmission oil / water heat exchanger autopsy

Yep. My car was well-maintained (at least after I bought it; there were prior owners), and the exchanger didn’t look like it was near failure. But I also think changing it was a good idea. The intake gaskets are a known issue, too. I’m not surprised at the condition of yours when they were pulled.

Others may think we’re nuts and wait instead for failure to change it. It’s a personal decision.

If you decide to change it, you may want to consider this unit. The maker claims it’s more robust than OEM. I have no affiliation with this and did not learn of it until after I did mine.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F311688625410


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Thx for the share. I see this in my future.

 

I did the same thing last year, it just makes sense to replace it while you have the plenum off. It's right there and the price you pay for the part is far less expensive than the failure. This was mine after 55k miles.

 

+1

I changed mine during my first major after purchasing the car.
I also installed that unit you wrote about. It is special built by the distributor and a side-by-side comparison showed the difference.
I am happy with it.

 

A plate heat exchanger would be a far better bit of kit , at least you could clean both sides.

 

Good call on your part. The exchanger on my 430 failed and caused all kinds of problems. Mechanic had to pull the transmission and clean and inspect every part of it.

 

I do not believe in 3 year oil changes on anything in the car. I have seen in my own clients cars less transmission problems, specifically syncro wear with annual changes. The sludge in the heat exchanger supports my position. Should be annual changes.

One of the top theories on heat exchanger failure is too high oil pressure in the exchanger due to clogging from sludge overstressing already weak solder joints.

 

Are the tube ends expanded or soldered into the tube plate ?

 

I have never cut one apart but the ones I have seen had a lot of solder work in them.

 

I was looking at the end plate and you can see the tube end is sort of pushed over- this is what they look like when they are expanded with a tube roller into the end plate. The ones i used to work on , in the steam turbine ships had about 6500 tubes about 22 feet long and say 3/4 inch bore- a lot of tubes to put a tube cleaning brush through when you had a condenser clean on the go.

 

OK, it's my turn to ask a dumb question.
Knowing that MOST of us idle our cars for a bit before we drive off and MOST of us don't drive them in bad weather (rain or snow)
what's the harm in bypassing the HX? I change my rad fluid and gear oil every 2 years.

 

How much hours does it take to replace the heat exchanger if it's done as seperate work?

BR
Gerhard

 

It took me about 3 months

 

Makes sense. What doesn't make sense is the formation of sludge when the transmission oil comes out looking new every time it is changed. I would think there is some indicator in the fluid, however cannot disagree with the evidence shown in this thread. My '99 Modena fluid always looks new.... although I only have around 25K on the odo.