Transmission temperature dash gauge versus Aladdin temperature reading?

[Rick Vyncke]

Traveled this past week in our 2004 Beaver Marquis (42,000 lbs) towing a large boat (8,500 lbs) through the Rocky Mountains in hot and dry weather.  There are two options for viewing the Allison transmission temperature: 1)  the dash gauge indicated the temperature got up to a high of about 220.  2) The Aladdin system indicated a high of about 240.  The engine was running between 185-205.

The high temps were not sustained over a long period and were seen (as expected) when climbing mountain passes and/or descending the same.  Most posts indicate that there is nothing to worry about until 250+.  Assuming that is true I should be OK... except that's getting a bit close to the danger zone for me.

I've read numerous posts here about transmission temperatures and so I won't ask to rehash that.  My question is...  which reading do I trust?  Is the dash gauge more accurate than the Aladdin system or vice versa?  There is a 20 degree difference between the two on the high end.  I suspect I'll have to take into shop where they can test the temperatures to find out which one is accurate and which is not.  Are there different sensors for each or are they both working from the same sensor?

Thanks

[David T. Richelderfer]

http://beaveramb.org/forum/index.php/topic,127.msg460.html#msg460

[Mike Shumack]

Yes, like the other thread said, the Aladdin uses the temperature gauge built into the transmission, the dash gauge uses an aftermarket sending unit screwed into the large cooler line coming off tranny running to transmission cooler.