Community Forums

cPaul · 08-14-2017, 09:48 AM

Went to add coolant and found pink foaming jelly on top of the coolant. It smells like transmission fluid. Every seen anything like this. We had just had the coach checked all over before we left on a trip. They had changed the coolant and put a filter on when we had it check. We are being told that the transmission fluid is leaking back into the coolant, no one has looked at it yet this is just from phone conversations and also we would need a new transmission maybe. cPaul

Old Scout · 08-14-2017, 09:57 AM

Perhaps--the tranny oil/fluid cooler is combined with the engine coolant radiator so a leak in one direction or another would contaminate one or both components. Havent heard of this happening but suppose it could. If tranny fluid leaked into engine coolant, radiator could be replaced [$$$$$$$] and engine coolant flushed. If engine coolant leaked into tranny fluid-this could be a major issue [tranny rebuild/replacement$$$$$$$]. Hope you can trust your repair facility to say/do the right thing. Think I would get an independent test [eg JB Labs]of both the engine coolant and tranny fluid to confirm cross-contamination.....

cPaul · 08-14-2017, 10:20 AM

We have talked to an Allison Transmission repair shop. They do not know where if we need a transmission cooler to get one. So I am seeking any information I can find on what is in the coach and where we might got one. If there are any ideas what might be causing this pink foam mixture other than transmission fluid in it I would like to hear them. Thanks

I'd be will to give a call to someone who has good information on this subject cPaul

Old Scout · 08-14-2017, 10:37 AM

Don't know about "good information" but will tell you that on earlier Alpines the tranny cooler in imbedded in the engine coolant radiator--so if leaking, you will have to replace the entire radiator....lots of info about radiator replacement on this forum for those with inquiring minds....until you get a lab analysis of both engine coolant and tranny fluid--hard to know what you have.....

cPaul · 08-14-2017, 10:51 AM

thanks we are planning on getting an analysis cPaul

wolfe10 · 08-14-2017, 10:52 AM

Pull a sample of the ATF and have it analyzed.

If ATF in the coolant, VERY likely there is coolant in the ATF. When the engine is shut down, there is zero pressure in the transmission cooler (integral part of radiator), but still residual pressure in the cooling system. So, leaks are almost always "both ways".

It takes very little coolant to contaminate the clutch plates.

Also a good idea to test the coolant. One of the primary causes of cooler failure is old coolant that becomes acidic and "eats" the radiator and transmission cooler.

Terry W · 08-14-2017, 10:54 AM

Just curious if you've taken a look at the trans fluid level or color. I'm on my phone so I don't know if your signature tells us where you are located, but if you put the word out, so to speak, someone will probably chime in with a name or two of a trusted shop close to you.

Terry

cPaul · 08-14-2017, 11:09 AM

The transmission fluid was down some but looks normal. It was when we went to add coolant we saw the pink foam. It had a new filter and coolant put in when we headed to Maine from Maryland at a dealer in PA. and we just drove from Maryland to Maine with three stops on the way. This was about a week after it had been in the shop. We are now in Trenton, Maine and the nearest Allison repair shop is in Portland that we know of, about 170 miles from here. They will send the fluid out to text it. If someone knows of something closer that's good cPaul

wolfe10 · 08-14-2017, 12:11 PM

If you do have to drive it someplace before repair, as soon as you turn off the engine (when transmission fluid PSI would drop below coolant system PSI) WITH THE PROPER PROTECTION, remove the radiator cap to de-pressurize the cooling system. That will minimize coolant contamination into the transmission.

Tom and Patty · 09-09-2017, 09:08 PM

Any update?

cPaul · 09-11-2017, 12:28 PM

The transmission cooler was leaking. We replaced the cooler, abandoned the old cooler, and all is working well. We are on the road again. Thanks for asking so far all is well. c Paul

Old Scout · 09-11-2017, 03:11 PM

My understanding is that tranny cooler is integrated inside the engine radiator--with the tranny cooler leaking--understand that you replaced with an after market, new cooler; but how did you "abandon" the OEM tranny cooler inside the radiator... seems like the abandon tranny cooler would continue to leak fluid into coolant? How did you determine if engine coolant had gotten into tranny fluid, and if so, how did you flush/refill tranny??????

cPaul · 09-11-2017, 04:01 PM

the leak was in the transmission coil leaking transmission fluid into the cooling water. I found pink foam in my radiator. I sent a sample of the fluid to a lab recommended by Allison. The after market cooler was installed into the piping running from the radiator to the engine and the transmission hoses were connected to the new cooler. the old transmission ports were plugged. the old cooler still has cooling fluid running through but no longer has transmission fluid running through it. the cooling system was flushed twice with Prestone radiator flush. I changed the transmission fluid and filters and all seems well after a 800 mile trip home. I hope this is helpful. Paul McLendon PS the cost of repairs was $ 4500.00

wolfe10 · 09-11-2017, 07:17 PM

It is EXTREMELY rare for a transmission cooler/engine coolant leak to be only one way.

Why?

When the engine is running, transmission fluid pressure exceeds coolant system pressure, so ATF ends up in the coolant.

When the engine is shut off, transmission pressure drops to zero. But the hot coolant and pressure radiator cap keep pressure on the coolant.

So, normal for any leak to be in BOTH directions.

Brett