LB7: overheating allison

[smininst]

1000 miles from home..Trans temp light comes on. Crawled under to find bottom cooling line very hot...top line slightly warm to touch. Air lock?
Trans fluid level 1" above full while hot. Need to drive 300 miles tomorrow for work on Monday. Noticed 250 degree temps for last few days at highway speed. Any suggestions?
2002 2500 HD Duramax 252,000 good running miles..
joe

 

[gmduramax]

Cooler blocked? Converter clutch delaminating?

 

[xcablb7]

happened to me when my filter fell off, the internal

 

[smininst]

latest test

Thanks for the response guys!
I will drop the pan and check the internal filter.

FYI
Prior to reading your replies I test drove truck about 18 miles. Temp reached 200 plus a bit. Felt that temp would continue to rise if I drove on so I crawled underneath after parking and shutting down. neither upper nor lower cooler lines were warm while the trans was hot. Seems like no circulation.

 

[smininst]

internal filter intact

Ok! That was fun. They have large stones here in KS that feel real good under the ole shoulder blades. Removed the pan ...filter intact. Installed a SS strap while I was at it to secure the filter in place. Now what? I'm going to remove the tuner and run it on stock setup to see if that makes a difference.

 

[smininst]

Allison overheating

Second test drive ...tuner detatched/running stock settings....temp steady at 175 to 185...stopped checked cooling lines...bottom line hot top line warm...trans hot like bottom line. I wonder if my troubles are over. I'll know tomorrow on long trip. Is it possible that the upper tube lower temp is actually cooled oil returning to the trans? Is it possible my DSG tuner caused the problem? I know it has an anti-slip feature to it.

 

[Smokin LB7]

Is it possible that the upper tube lower temp is actually cooled oil returning to the trans?

I dont know if I understand this right, but the lower line runs fluid to the cooler, and the upper line returns the fluid from the cooler. So yes, the upper line is returning cool(er) fluid from the heat exchanger