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Topic: Transmission Cooler (Read 650 times) previous topic - next topic

Transmission Cooler

Well, I had mine changed out today and in looking at the old rusted unit, I spied a large chunk of solder about the size of a 50 cent piece blocking some of the the tubes.  I could not pass thru the tubes but it could block up a number of them if it was flat against it.  There was some corrosion and it looks like the previous owners had put in Barrs Leak too.  The solder was flat on one side and very rough on the other though it had been smoothed down too so I am sure there was some that was worn off.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Transmission Cooler

Reply #1 –
Sad John, when my radiator was replaced with the CAC, the transmission heat exchanger was Inspected closely, pronounced "Good", many new hoses both hydraulic and radiator coolant. Hoping for another 100,000 mile trouble free. Sure no heating issues.  Also had both fan motors cleaned & resealed.

Re: Transmission Cooler

Reply #2 –
Looks like the blob of solder broke away from inside tubes etc when it was being made. Sloppy and could have caused big trouble had it been smaller?
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Transmission Cooler

Reply #3 –
Yes, it could have cause a big issue but it was odd to find. 
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Transmission Cooler

Reply #4 –
The thing is that it is perfectly flat on the bottom of it like it was laid on a piece of steel and then moved in there.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Transmission Cooler

Reply #5 –
The way it was described to me is that The transmission fluid moves through the small tubes and the engine coolant through the big tube that all the small tubes are in.  It you spring a leak, your transmission gets contaminated with engine coolant.  Good reason to make sure when coolant and transmission fluid are lab tested that they check for cross contamination.  Pretty pricey repair if the transmission gets coolant in it.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Transmission Cooler

Reply #6 –
It looks like a big bundle of straws inside the big tube.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Transmission Cooler

Reply #8 –
Quote from: Roger & Susan in Home2 –
The way it was described to me is that The transmission fluid moves through the small tubes and the engine coolant through the big tube that all the small tubes are in.  It you spring a leak, your transmission gets contaminated with engine coolant.  Good reason to make sure when coolant and transmission fluid are lab tested that they check for cross contamination.  Pretty pricey repair if the transmission gets coolant in it.

Hi Roger,
You are correct, that is exactly how it works. 
We call them shell and tube heat exchangers.  They are used in industry like nuclear power and oil refineries all the way down to small transmission coolers like the kind that are found on a FT.
Here is some light reading if you are interested.

Shell and tube heat exchanger - Wikipedia, the free encyclopedia

In an automotive application like a motor home, what is usually done is that the cooler water from the bottom of the radiator is directed from from the engine water pump, to the transmission cooler then back to the engine.

It really does just look like a pipe with a bunch of straws in it.

One of the many hats that I have worn is working in a radiator repair shop.  We test shell and tube coolers all the time.  It is a simple process which involves cleaning, flushing then pressurizing with compressed air and immersing into a test tank to see if there are any leaks.  The problem is if there is a leak to resolder the tubes is not easy to the point that the shop will not do it or if customer insists, there is NO WARRANTY.

On an Allison transmission, coolant into the trans fluid is not a good thing.  Something in the coolant will cause the friction material of the clutch pack to de laminate.  Very bad, not to mention what it does to the bearings.

I have noticed that Lots of members of this forum sample and test their transmission fluid.  This is with out a doubt one of the cheapest and best things you can do to keep your Allison rolling.  If you ever get a report back with ever a hint of glycol in the trans fluid, a retest ASAP is in order.

I have been around Allison's for years, nothing as small as what is run in a FT, but they all work the same. 
Heat, dirt and glycol are killers.

I hope that I am not boring people with all my technical posts.

If anyone has any questions, please feel free to ask

Brian
Foretravel owner wannabe

Re: Transmission Cooler

Reply #9 –
The problem is that if the heat exchange should spring an internal leak, most of the time it's too late to keep a fatal dose of glycol out of the trans. And then the transmission has to be completely torn down. This is what happened to Roland. Too late to close the barnyard gate when the animals are out. Not hundreds but several thousand to overhaul the trans.

Check the super duty exchanger on a U300. It still could develop a leak, just a little less likely.

Just another reason I hate automatic transmissions. Luxury Euro buses use manual transmissions and shift like glass. You can't even get an unrestricted European driver's license unless you can drive a stick.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)