Trans Cooler - Heat Exchanger leaking

Topic: Trans Cooler - Heat Exchanger leaking (Read 8728 times) previous topic - next topic

Trans Cooler - Heat Exchanger leaking

December 29, 2024, 08:05:46 am

After replacing the radiator and testing. I have a leak in my least expected spot. It appears to be a pin hole in the casing of the trans cooler. Pretty disappointing after all this work to install the radiator and relocate the trans cooler supports. I assume it is from cleaning it up and painting it. Been trying to find all the threads about this subject. Not a lot of recent ones but I suspect not much has changed (except prices!). For my 99 U320 the replacement appears to be Rocor P/N 3-1279B. I see Rocor has been sold to Kelvion. Looks like that crosses to their P/N: 28601-3436-B. I was debating having mine repaired. I could weld a pin easily if the rest of metal was decent. But after reading about what happens if this should fail and coolant gets in transmission, I may just replace it. More coach bucks. A LOT of coach bucks this year. I am sure this will snowball into something else, like the trans fluid hoses when I try to disconnect them from the trans cooler. I did not remove them when doing the radiator, just supported it under the coach. But hoping to have a solid FT when I am done. I would welcome any input from anyone that had to deal with this recently and thank you FT community.

Re: Trans Cooler - Heat Exchanger leaking

Reply #1 – December 29, 2024, 09:47:28 am

I posted this in the other thread before I realized you started a new one.

Seeing that depressed me and its not my coach, I'd still be laying on the ground muttering. Of course it has to be at one of the low points of the system, ensuring you would have to drain the entire system to do a full repair.

Curious when you changed everything out, did you also do a Restore flush? Just asking in case there was some Bars Leaks that had masked the problem that got flushed out.

I assume its the same cooler that we have, Rocore 3-1279B which has the BTU rating Allison wants for the "R" retarder series of the 4000. It would have been nice if it was the 5 series (5-7027B) which has the replaceable end caps (bonnets) as you could get those caps fairly cheap.

I've attached a Rocore catalog and BTU data for you, keep a watch on Ebay should you decide to replace the unit. Also a good read Rocore Floating Bundle Trans Cooler On the Cheap

Re: Trans Cooler - Heat Exchanger leaking

Reply #2 – December 29, 2024, 10:24:24 am

Quote from: steve – December 29, 2024, 09:47:28 am

I posted this in the other thread before I realized you started a new one.
Seeing that depressed me and its not my coach, I'd still be laying on the ground muttering. Of course it has to be at one of the low points of the system, ensuring you would have to drain the entire system to do a full repair.

Curious when you changed everything out, did you also do a Restore flush? Just asking in case there was some Bars Leaks that had masked the problem that got flushed out.

I assume its the same cooler that we have, Rocore 3-1279B which has the BTU rating Allison wants for the "R" retarder series of the 4000. It would have been nice if it was the 5 series (5-7027B) which has the replaceable end caps (bonnets) as you could get those caps fairly cheap.

I've attached a Rocore catalog and BTU data for you, keep a watch on Ebay should you decide to replace the unit. Also a good read Rocore Floating Bundle Trans Cooler On the Cheap

Thanks for the info. I had already found your thread on the subject and read it thoroughly. I have already been on the search path. I did see the original type with the new P/N for $2k. So far that is the cheapest option. But the search goes on......
Oh and I did not flush the system since the coolant was not that old and was very clean.

Re: Trans Cooler - Heat Exchanger leaking

Reply #3 – December 29, 2024, 11:02:12 am

In a way be happy the leak is on the outside. Common for these coolers to fail internally and usually put coolant into the transmission. At this age it owes no one anything. Being the upgrade fool that I am I would probably look to replace that cooler with an air heat exchanger.

Re: Trans Cooler - Heat Exchanger leaking

Reply #4 – December 29, 2024, 12:06:56 pm

I bought one March of 2020 off Ebay. they come with the wrong ends attached but they sell you the correct ones to switch them out. It is still sitting with the rest of my spare and to do list parts.

Re: Trans Cooler - Heat Exchanger leaking

Reply #5 – December 29, 2024, 02:41:19 pm

Quote from: RvingJeff – December 29, 2024, 08:05:46 am

After replacing the radiator and testing. I have a leak in my least expected spot. It appears to be a pin hole in the casing of the trans cooler.

Hey Jeff, are you sure it's a failure of the trans cooler itself? The photo's not great but it looks like it could be leaking from the hose connection to the cooler. Maybe I'm just wishful thinking. You said it was dripping. How much was it leaking and did it stop after it cooled down?

Re: Trans Cooler - Heat Exchanger leaking

Reply #6 – December 29, 2024, 03:12:51 pm

Quote from: Geodmann – December 29, 2024, 02:41:19 pm

Hey Jeff, are you sure it's a failure of the trans cooler itself? The photo's not great but it looks like it could be leaking from the hose connection to the cooler. Maybe I'm just wishful thinking. You said it was dripping. How much was it leaking and did it stop after it cooled down?

Unfortunately, it is the cooler. I took the pic after it had cooled off a bit and was just running down the cooler. When I first checked it after a test drive and it was nice and hot. It was like a small needle size stream shooting out the cooler right by the hose inlet.

Re: Trans Cooler - Heat Exchanger leaking

Reply #7 – December 29, 2024, 03:49:34 pm

Not seeing it up close and personal I can only guess, but if it was mine and I didn't have a spare I would power wire brush the area and put a small sheet metal screw with a fiber washer to stop the liquid then clean with alcohol and then completely cover the screw and surrounding area with JB weld. The pressure cap of 16 psi keeps the pressure at that.

Re: Trans Cooler - Heat Exchanger leaking

Reply #8 – December 29, 2024, 05:00:57 pm

If you can take the cooler off or at least drain the antifreeze side down and remove the hose fitting. This will let you give the inside a look to see if it is stopped up with gunk of some kind. If the tubes are mostly clean then clean up the area like Cman describes. Here is where I would break out the 56% silver solder (or 46% if that is all that is available in your area) and solder that little crack up. This would buy you some time to make some choices as to which direction you want to go in the future as there are several options.

Mike

Re: Trans Cooler - Heat Exchanger leaking

Reply #9 – December 30, 2024, 09:03:58 am

I found new old stock. I called the company and talked with a real person. Verify it is new open box and just may have external scratches and blemishes. They are on eBay as well with 100% positive rating. Ordering direct had free shipping so cheaper than eBay.
I know this the same as original and not the new floating type, but that does not bother me with this type of use.

Western Star Heavy Duty Oil Cooler With Retainer - P/N 28601-3436

Thanks all for the suggestions and support!
Jeff

Re: Trans Cooler - Heat Exchanger leaking

Reply #10 – December 30, 2024, 01:59:49 pm

Sometimes it just doesn't pay to disturb stuff, unfortunately.
I did a similar thing when I removed the rad overflow tank, wire brushed it and painted. New leak, but JB welded it and it's been fine.

I wonder if they have more than one. Although 2K is a hard pill to swallow for a spare part. Never ends.

Re: Trans Cooler - Heat Exchanger leaking

Reply #11 – December 30, 2024, 07:04:13 pm

I one day wish to kinda follow what Crainman did and go to the new style, but upsize it for better retarder use. They do make a bigger size.

Re: Trans Cooler - Heat Exchanger leaking

Reply #12 – December 31, 2024, 09:45:12 am

Did a lot of searching and not coming up with definitive answers. I was hoping to figure out the fitting size of the hose for the trans cooler so can get caps when I remove the hoses. I can see it looks like a JIC or flare fitting. I see from the cooler documentation it is a 1.625-12 UN-2B O-RING Boss. But nothing on the fitting used for hose end in the Foretravel application.
My best guess so far is https://ph.parker.com/br/en/product/triple-lok-37-flare-jic-tube-fittings-and-adapters/24-c5ox-s
That would make the cap 1 1⁄2 JIC-24
Also I was looking for the hoses in the Foretravel documentation which would tell me the size as well. But I had no luck.
Just throwing out there in case anyone knows. Once I do get the info I will put it here for future reference

EDIT:
For correct fitting size see post #18

Re: Trans Cooler - Heat Exchanger leaking

Reply #13 – December 31, 2024, 12:07:15 pm

Just thinking stupid here, is there enough slack in the hoses to raise them up above the trans fluid level and tie them while changing the cooler. I have not looked at mine. Jim.

Re: Trans Cooler - Heat Exchanger leaking

Reply #14 – December 31, 2024, 12:40:25 pm

Quote from: fourdayoff – December 31, 2024, 12:07:15 pm

Just thinking stupid here, is there enough slack in the hoses to raise them up above the trans fluid level and tie them while changing the cooler. I have not looked at mine. Jim.

That is my thought too and I believe that would work. But I would like to remove then and soak them in a rust remover. They are very rusty and if they do not clean up good debate replacing. So the caps would be for the transmission end.

Re: Trans Cooler - Heat Exchanger leaking

Reply #15 – December 31, 2024, 01:48:24 pm

Quote from: RvingJeff – December 31, 2024, 12:40:25 pm

That is my thought too and I believe that would work. But I would like to remove then and soak them in a rust remover. They are very rusty and if they do not clean up good debate replacing. So the caps would be for the transmission end.

What about some spray Limeaway or CLR. Jim.

Re: Trans Cooler - Heat Exchanger leaking

Reply #16 – December 31, 2024, 02:00:01 pm

If your 2000 is anything like my 2003, the hoses are pretty short. I don't know if you could get a hose crimp tool on them. The front one is longer than the rear.

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Re: Trans Cooler - Heat Exchanger leaking

Reply #17 – December 31, 2024, 06:01:19 pm

Being 20+ years old those hoses will not handle much man handling them.

Re: Trans Cooler - Heat Exchanger leaking

Reply #18 – January 01, 2025, 06:08:30 pm

Wanted to get cooler out before it turned terrible cold. Well I think I found the issue. Just look at the pic after a little cleanup of the spot. One of the fittings came loose and spun like it was supposed to. The other did not and would not break free. I was able to get the connection free so I literally just spun the trans cooler around and around until it was released. At some point the hoses will have to come out and see what I can do with them.
To follow up on the size of the fittings. They are
https://ph.parker.com/br/en/product/triple-lok-37-flare-jic-tube-fittings-and-adapters/20-c5ox-s

Also elevating the trans hoses does work. They do not drain.

Re: Trans Cooler - Heat Exchanger leaking

Reply #19 – January 01, 2025, 07:34:58 pm

Looking at it now I would just braze it instead of the screw and JB weld idea. But you have already gone the best way to have it last another 20+years.

Re: Trans Cooler - Heat Exchanger leaking

Reply #20 – January 01, 2025, 10:11:02 pm

Wow, that is a sizeable hole. Any idea on what happened, is it rust , wear through, or damage point?

Glad you were able to get it out without loss of fluid, transynd is not cheap.

Re: Trans Cooler - Heat Exchanger leaking

Reply #21 – January 01, 2025, 10:42:10 pm

I would weld it and then I would have it cleaned and tested.

Re: Trans Cooler - Heat Exchanger leaking

Reply #22 – January 02, 2025, 07:06:46 am

Quote from: steve – January 01, 2025, 10:11:02 pm

Wow, that is a sizeable hole. Any idea on what happened, is it rust , wear through, or damage point?

Glad you were able to get it out without loss of fluid, transynd is not cheap.

Rust for sure. Cleaned around that area a little more and another hole popped up. As mentioned I think it could be repaired. Already have the other one on the way and it just makes me feel better. No incident on the road.

Re: Trans Cooler - Heat Exchanger leaking

Reply #23 – January 02, 2025, 10:45:07 am

Quote from: RvingJeff – January 02, 2025, 07:06:46 am

Rust for sure. Cleaned around that area a little more and another hole popped up. As mentioned I think it could be repaired. Already have the other one on the way and it just makes me feel better. No incident on the road.

I so agree. I do not want to ever do major repairs on the road.

Re: Trans Cooler - Heat Exchanger leaking

Reply #24 – January 17, 2025, 03:47:22 pm

Finally over 30 degrees today. I wanted to get the trans cooler hydraulic hoses out to inspect and break loose the end that will not spin. Came off from the trans end pretty easy. My son 3d printed a couple of caps for the trans end. I put the end that was seized up in a vice. Then with a 2" socket, penetrating fluid and an Impact I was able to break it loose. Got the new cooler and found some new fittings on eBay for less than a 1/4 of the cost anywhere else. Not sure how long it will be before I am ready to put it all back together but I am not in a rush. Not going to drive it on these salty roads around here.

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