Normal trans temp

[Jerry Carr]

We now have our 06 Beaver Thunder back after 6 months of part waiting, the folks (Tom) at Massey Diesel AZ did a great job once all the parts came in from Monaco. I drove about 20 miles to spend a night/day cleaning things up. While driving, I had on my Aladdin an engine temp of 194-197.  The outside temp yesterday was about 90. The engine temp seems OK but the transmission temp was 187- 205. I know that I had not moved the rig in 6 months, but I also didn't think my transmission had been running this high. I call Tom at Massey and he said it was OK. Any comments??

[Lee Welbanks]

Jerry,

Do you remember what your trans temp was before? In a 20 mile drive I find it hard to believe that your trans was that warm, On my PT the trans temp has only hit 200 or 205 on a long steep pull heading to the tunnel at the top of I-70 in Co.

[Gerald Farris]

Jerry,
On flat Interstate driving the transmission temperature on most Beavers usually runs within 10 degrees of the engine temperature unless the coach has had an air to air cooler added. The transmission fluid is cooled with the engine coolant and seldom runs much cooler than the engine. On cold morning start ups the transmission fluid is also heated by the engine coolant to get it up to operating temperature faster.

The transmission will run much hotter than the engine in stop and go driving because the torque converter creates a lot of heat if you are stopped and idling with the coach in gear. It also runs a little hotter on long steep pulls. The other thing that can make your transmission run hot is engine coolant in the fluid from a leaking heat exchanger, but your temperatures do not sound out of line with the transmission only 7 degrees different than the engine. 

Gerald

[Jerry Carr]

Thanks for the info Gerald, what is the high limit for trans temp? I was told 240 is this correct?

[Bill Sprague]

http://www.rvtechlibrary.com/transmissions/3000_4000_operators.pdf

The Allison book, on page 36, lists three temperatures.  The maximum "sump" temperature is 250.