Allison 3000 HS blunder..

ctooraen · 02-04-2012, 10:25 PM

Hi all,

First post here. I'll try to keep it to the point as much as possible. Have 2005 Freightliner M2-106 with MBE926 engine running 330/1000 with Allison 3000HS tranny and full air brakes.

Been traveling a bit this winter and we are currently at the NuWa factory in Chanute KS. Anyhow lots of short trips, so to keep some heat in the engine, i've been running at high idle (1000 rpm) when parked for a bit.

Well today, I parked and left at high idle for about 10 minutes to run into our 5th and take care of a few things. I noticed the fan cut on and I knew that something was amis.

When back out to truck, got in and noticed engine coolant temp at 205 or so, and tranny around 230-240. No check tranny light, or check engine light.

Well it was simple. My stupid self left the truck in drive when I set the parking brake. Thank god for good brakes!! So immediately put in reverse, and drove truck to cool down. Temps immediately dropped to around 200, and trans shifted fine (actually better then when at 110, that is normally runs at). No issues, no noises, limp-in, etc. Drove about 10 miles, and after it cooled down to 140 or so, checked fluid level and condition, and all was fine. No burnt smell, clean amber color (new transynd).

Manual says that if sump temps exceed 250 for at least 15 minutes then it will set a code.

So thoughts on this? Anything I should be aware of? My main concern is the torque converter since that is was generated all the heat will sitting in drive on high idle. Granted the idle was only 200 rpm above max level of 800, I just am wondering if the converter was overheated in this situation.

Thanks again.

Charles

**Gary RVRoamer** · 02-05-2012, 09:10 AM

If you aren't using synthetic tranny fluid, you may want to consider a fluid change. Synthetics hold up very well at higher temps, but non-synthetics tend to deteriorate as temperature goes up.

Other than that, I don't see a big reason for concern. You might encounter temps like that pulling a long grade - or going down one with the engine or exhaust brake engaged.

ctooraen · 02-05-2012, 10:20 AM

Quote:

Originally Posted by Gary RVRoamer

If you aren't using synthetic tranny fluid, you may want to consider a fluid change. Synthetics hold up very well at higher temps, but non-synthetics tend to deteriorate as temperature goes up.

Other than that, I don't see a big reason for concern. You might encounter temps like that pulling a long grade - or going down one with the engine or exhaust brake engaged.

Yes Gary, it does have a brand new fill of Transynd. About 1700 miles on the filter and fluid change. Thanks for the opinion.

Cat320 · 02-06-2012, 10:07 AM

Is your rig supposed to have a buzzer sound when the parking brake is engaged and it is in any gear except neutral? I get a loud buzzing sound when I do that.