Torque Converter Cooler/Heat Exchanger Issue

[Adam Lofting]

Hello Everyone,

This is my first post so I apologize for any misuse of the forum.

I have a 2005 Dodge Ram 3500 5.9l. About a month ago, my transmission started to slip. I took it into my transmission shop, who had done the rebuild about 6 years ago, and they informed me that the rear cooler or torque converter heat exchanger was mixing antifreeze with transmission fluid. The cooler would need to be replaced and the cooling system would need to be flushed until the transmission fluid was removed. After that the transmission would need to be rebuild and the system flushed as well.

My questions to everyone:
-Has anyone else experienced this and thought of a way to detect when this occurs to be able to save the transmission from a total rebuild?
-Am I incorrect to think that an aftermarket temperature gauge could detect this issue?
-Was it a bad move to buy an aftermarket cooler online for $150 instead of the OEM cooler for $1200?
-Was it also a bad move to replace the 4 pre-formed 90 degree rubber hoses, that would have cost me over $400, with bulk 1/2” bulk cooler hose that I ran at a much softer/longer bend?

When this happened, and the quote to fix it came in at $6300, I jumped to the conclusion that I was going to sell the truck for parts and buy a 2015 to newer truck. It took me a while and a few test drives to decide that I was going to keep the truck and start on its rehabilitation. These are simple trucks, compared to the newer ones, and these engines are known to go for 500km plus. I am not looking to modify/chip my truck but just do everything I can to keep it running for as long as possible.

Sorry for so many questions on one forum. I have been fighting with these thoughts for a while now and I could really use some advice from anyone who has gone through or is going through a similar situation.

Thank you

 

[Ozymandias]

Short, these oil/water heat exchanger are in general very reliable.
The only thing they can't stand is if you use only one wrench putting on the lines and don't use a counter wrench.
The 90° elbows are available in any parts store for small money.

 

[sag2]

I'm not sure I completely understand your questions.
Is there still fluid and coolant mixed together in the cooling system and the transmission? Did they find clutch debris in the transmission? The worst possible thing to do is leave the coolant in the transmission. Any water in the coolant will start to rust steel parts in the trans and attack bushings.
If your shop is telling you that the trans needs a $5k overhaul they are not being honest. It more than likely needs clutches and seals only. Unless it is already rusted inside they should be able to freshen it up for a couple grand.
So if you want to minimize damage, drain the coolant completely. Then go get a couple cases of ATF and flush it a couple times using the cooler line to catch the used fluid. Get the least expensive fluid, Wal-Mart sells Dexron in gallons. The trans is already hurt, so the wrong fluid isn't going to matter in this case. It is more important to get the coolant out.

 

[BigPapa]

Heat Exchanger failure is common on the 3rd Gens. I’ve seen several. Comparatively, the 2nd Gen Exchanger is pretty much bullet proof except for a self-induced issue as Ozy said. If I had a 3rd Gen, I’d just do away with it. The only real way to catch it is to constantly check your transmission fluid and coolant.

As far as your use of bulk hose, it will be fine as long as it’s rated for transmission fluid.

 

[Adam Lofting]

I'm not sure I completely understand your questions.
Is there still fluid and coolant mixed together in the cooling system and the transmission? Did they find clutch debris in the transmission? The worst possible thing to do is leave the coolant in the transmission. Any water in the coolant will start to rust steel parts in the trans and attack bushings.
If your shop is telling you that the trans needs a $5k overhaul they are not being honest. It more than likely needs clutches and seals only. Unless it is already rusted inside they should be able to freshen it up for a couple grand.
So if you want to minimize damage, drain the coolant completely. Then go get a couple cases of ATF and flush it a couple times using the cooler line to catch the used fluid. Get the least expensive fluid, Wal-Mart sells Dexron in gallons. The trans is already hurt, so the wrong fluid isn't going to matter in this case. It is more important to get the coolant out.

Thank you for the reply. That is what I did. Unfortunately the damage had already been done to the clutches. I actually had two shops quote on it and they both wanted to replace the torque converter as well. The work is done now. I am just looking for opinions on ensuring this does not happen again in the future.

 

[Adam Lofting]

Heat Exchanger failure is common on the 3rd Gens. I’ve seen several. Comparatively, the 2nd Gen Exchanger is pretty much bullet proof except for a self-induced issue as Ozy said. If I had a 3rd Gen, I’d just do away with it. The only real way to catch it is to constantly check your transmission fluid and coolant.

As far as your use of bulk hose, it will be fine as long as it’s rated for transmission fluid.

Heat Exchanger failure is common on the 3rd Gens. I’ve seen several. Comparatively, the 2nd Gen Exchanger is pretty much bullet proof except for a self-induced issue as Ozy said. If I had a 3rd Gen, I’d just do away with it. The only real way to catch it is to constantly check your transmission fluid and coolant.

As far as your use of bulk hose, it will be fine as long as it’s rated for transmission fluid.

BigPapa,
I agree. This part just seems like a ticking time bomb. I figured someone out there must have come up with a solution to eliminate this. A $200 part causing $6300 in damage!

Also, who checks their transmission fluid and or coolant that often. Why not just have a larger or secondary air cooler in the front?

 

[BigPapa]

Also, who checks their transmission fluid and or coolant that often.

That was my point.

The HE is more of a temperature regulator than a cooler. It warms the fluid when it’s cold and it will cool the fluid if it’s hotter than the coolant. Your transmission cooler is mounted in front of your CAC.

 

[sag2]

Because a coolant to fluid cooler is by far more efficient than an air to oil cooler.

 

[Timd32]

You can bypass that HE with a simple line set. If you have your old one use it as a template and have one made up with the correct fittings.