ranchmink

Question about Allison Transmission

16 posts in this topic

Hello

I have an 1997 Safari coach with Allision Transmission, 3000. I am getting ready to add a transmission cooler since my coach only has the radiator as the cooler for the transmission fluid. I need to know which line from the transmission is the out flow line, upper or lower from Transmission.

My goal was to take the outlflow line from the transmission and put an inline cooler in place it as a precooler before the fluid gets to the radiator to keep BTU's out of the radiator. It seems when ever my coach starts to run warm so does the transmission.

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ranchmink,

Several factor are in play here. How long since the transmission was serviced? It may need the filter changed and fluid replaced.

Where does the rise in heat happen? In the summer or winter, in the mountains or flat land.

Have you had your coolant checked? Your coolant may need to be drained, flushed and replaced. As deserdeal said you may have a fan problem not moving enough air when under a load.

As I said, many factors.

Herman

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You might consider just using a standalone cooler with a fan and not run it through the radiator.

Actually, I much prefer ranchmink's auxiliary cooler, THEN in-radiator cooler unless you are always in sub-tropical climates. A stand alone cooler can OVER-COOL in low ambient temperatures.

And, Herman asked some good questions-- let's narrow down what overheats (from transmission temperature gauge if you have one) as well as engine coolant gauge.

If it is engine coolant temperature that rises, followed by a rise in transmission temperature, attacking the root cause would be preferable.

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Actually knowing what temperatures he is seeing would be helpful. Running on the hot side is different than overheating. 250 degrees seems to be the line. This transmission measures the sump temperature. I am assuming he has some device installed to measure the transmission temperature and can provide the ambient temperature as well.

We don't know where he lives or the grades of the roads he travels. It would be helpful to know the terrain where he sees the temperature rise. If you in the mountains and seeing temperature increases going uphill, or seeing larger temperature increases coming downhill the determining factor may be the speed of the coach. Doing 70 up and down hills will generate a lot more heat than 60. Knowing what speed he has the cruise control set to on a relatively level Interstate would also be helpful.

Running the transmission at below the recommended operation temperature is not good and if he is in the cold belt the transmission may never get up to operating temperature.

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Hi

I thank everyone for giving me feedback on my issue. More facts:

  1. Transmission model MD 3060, anyone can tell me where to download a manual would be helpful
  2. I replaced the radiator last season with a new radiator.
  3. The majority of my driving is summer western USA with many grades. When the coolant temperature goes up so does the transmission. Never had any issues with winter trips, went to Park City in the winter no issues, but temperature did increase but not to the point of concern. On a recent trip the coach overheated and transmission hit 230 plus, the engine check light came on. When I added the secondary radiator went on a trip with no issue on the radiator side but on hills transmission and coolant went up together which I would expect. We have many long grades in the west and ambient temperatures in the 110 degree range not uncommon.
  4. I usually tow a trailer with a vehicle on it.
  5. Seldom use cruise control. Normally drive at 60-65 seldom go over as fuel mileage tanks.
  6. Since it has been increasing temperature, I have been gearing down for hills to keep the revs us and drop speed. I did recently add a secondary radiator which helped coolant temperature and did assist the transmission temps.
  7. I plan on adding the transmission cooler, found one on ebay good for Allison transmissions. I was planning on putting in as a precooler with an electric fan, thermo dyne brand. I will set up the fan with a thermo switch to turn it on and off based upon fluid temperature.
  8. I did plan on fabricating a cover to put over the transmission cooler for running in cold weather to stop air flow. I have read and understand the issues on running to cool. Once I was in Canada and blew the transmission lines off of the fitting due to fluid to thick to flow in cold weather.
  9. I was going to change the coolant and filter when I add the cooler.

Back to my original question I need to know which line comes out of the transmission is and which one is return. I wanted to put the cooler on the out line.

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Before deciding to treat one of the symptoms (transmission temperature) please make sure the root cause has been addressed.

On a rear radiator DP, start by VERIFYING that the front of the CAC (Charge Air Cooler) is clean. This normally needs to be cleaned annually.

Raise the bed. Shine a strong flashlight inside the fan shroud/between fan blades. Verify that the perimeter, particularly lower perimeter is as clean as the center (the fan blades sling the dirt to the perimeter). Often, restricted air flow through the CAC and radiator causes your symptoms and a simple cleaning can restore your cooling system to its original capacity.

The Allison MD3060's torque converter is locked up in "high" second, third, fourth, fifth and sixth gear, so the transmission is not a big heat factor, even on steep grades. But, higher coolant temperatures in the radiator DO affect transmission temperatures.

As a side note, be sure you grease the zirk on the fan hub on your Caterpillar 3126. It is between the head and the pulley.

Brett

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Richard

Thanks for the link but my unit is a MD3060 and the manual did not apply, any idea where I can find a link for MD3060?

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With everything cold start engine apply brake put in gear and press on accelerator to slip converter no more than a few seconds shut off engine and feel lines. Output from trans will be warmer.

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Also... if you haven't converted to TranSynd, I'd do it. My Allison (in a Monaco Exec 43') is much happier. While it does push up toward the temperature redline in summer mountain driving in NY state, it never gets beyond it.

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TranSynd (or one of the other TES-295 approved fluids) is always a good idea. Besides, once you change it over (using the double drain and refill method) you're pretty much "fill for life" at that point. Just change the filters every 75,000 miles and take an oil sample once a year.

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I have a 2007 Safari Passage with a Workhorse Chassis. It has an Allison transmission in it than I understand normally is attached to a diesel drive train. We bought the MH when it was new, but only have 7.000 miles on it right now. I get advised everytime I ask about it that it looks good. level is good and since I don't have a lot of miles on it, I don't need it changed. The MH sits for most of the time, with short trips (50 miles or less) every now and then. All other service is up to day. Should I be concerned about the Allision Transmission fluid? I don't have any electronic indicators on the transmission and it seems to work great. I would like to add that I have never had any problems with the Workhorse or Allison parts of this MH. Every problem so far has come from where Monaco got involved, as in the coach. So. Do I have a problem I have to worry about? In the past, I normally ignore the transmission until my service person says to change it. No one has said change it. Thanks for your attention.

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Hi Ted,

Welcome to FMCA !

The only item I would question is the age of the fluids. Over time condensation can build up in the engine oil and transmission fluid.

That would happen in your case because things do not get hot enough, few and very short runs.

Have you had the engine oil changed?

Most of the coolants will last for 5 to 7 years.

Rich.

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