Allison mt643 operating temp

[nwarner2010]

I'm about to make a 1000 mile trip from NY to Alabama in my bus with quite a heavy load. Does anyone know what the operating temp should be for the mt643 and what temp I should stay below? Can't seem to find anything referring to temps.

Thanks

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[Tango]

An automatic should stay around 200 degrees. It is the oil, not the transmission that determines longevity. Take a look at the 2 charts about half way down the page below. The numbers are pretty much identical to what Allison has published for "conventional" fluid. The newest synthetics are considerably more forgiving of temperature.

What transmission temp is normal? - iRV2 Forums

[nwarner2010]

Tango, thanks just what I was looking for! I think I was running around 175 degrees when the bus was empty. I'll keep an eye on it with the bus fully loaded. I don't for see any issues though.

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[cadillackid]

the fact its winter should help you as your radiator coolant temperature will run lower.. if you take it fairly easy on the bus you'l keep those temps nice and low..

the transmission cools itself via a couple loops in your radiator so wit hthe cold outside weather the radiator fluid can do a nice job of helping keep your tranny cool.
-Christopher

[superdave]

mine would run about 130, it would go a little higher climbing hills

[DoubleO7]

If the tranny cooling is incorporated into the engine rad, the engine will induce it's heat into the tranny.
The tranny will then be in sync with engine temp. even tho it might run cooler if it had an independent cooler.

[cadillackid]

Originally Posted by DoubleO7

If the tranny cooling is incorporated into the engine rad, the engine will induce it's heat into the tranny.
The tranny will then be in sync with engine temp. even tho it might run cooler if it had an independent cooler.

it well help to sync it to the RADIATOR temp in the tank where the cooler is.. in cold weather the radiator is often colder than the engine as the thermostat limits coolant flow to keep the engine at its normal operating temperature...

-Christopher

[Tango]

Correction...I should have said..."An automatic should stay BELOW about200 degrees."

[DoubleO7]

Originally Posted by cadillackid

it well help to sync it to the RADIATOR temp in the tank where the cooler is.. in cold weather the radiator is often colder than the engine as the thermostat limits coolant flow to keep the engine at its normal operating temperature...

-Christopher

Yes, true.
Being in Florida, it does not take as long for engine, rad & tranny to be at the same temps.
Other locations might take forever.

[cadillackid]

Originally Posted by DoubleO7

Yes, true.
Being in Florida, it does not take as long for engine, rad & tranny to be at the same temps.
Other locations might take forever.

im up at my house in ohio and friday night a group of 8 of us took a bus ride to wheeling wv to see some fantasticchrostas displays.. it was in the low 20s outside.. I was running the bus at 65.. and the engine temp was running about 185 or so.. (we had a LOT of the heaters on).. my Trans temp gauge went up to 125 Once when we were climbing a grade...

-Christopher

[nwarner2010]

Just thought I'd follow up here. I was pretty much at max weight and my transmission temps didn't seem to go above 170.

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[cadillackid]

the lockup torque converter makes a HUGE advantage in helping to keep a transmission cool..
-Christopher

[bigskypc50]

After driving my bus home about 100 miles, The trans temp could hardly be read on the dash so maybe 110, pulling homestake pass 6% grades cont. divide and all it maybe hit 120 with it down shifted at 35MPH into 3rd.