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Discussion Starter #1
Hi Guys great site, information is King, lots here. Been a member for a while never posted.
2004 Chevrolet Silverado 6.6 LLY 4Dr. Crew LWB 155,000+km totaly stock, some towing, 40' Cigarette.
Here's one for GMCSID, Mike L. or any other Allison Hydrologist out there.
Looked under truck today, the dreaded "red" bleeding in the snow under Trany, crawled under, not coming from spin on filter, coming from further forward on housing where butts to motor, then migrating down case toward filter. Truck was serviced in Nov06, outside case dry as a bone then, has not been driven much since, maybe 20 miles, has been cold 0F to -30+F truck started weekly or less, always fires right up after glow plug indicater out. Even with high idle on & winter front, these ISUZU's take a long time to warm up, over 1/2 hr. at -30F for water Temp gauge to even move. & yes my Pink Lemonade cooler is topped up. The Ally does not like the cold (F****** Frozen):( either. Tranny dipstick shows 1/8 " low warmed up at operating temp. so has not lost much blood yet. I'm familar with the basic operating principle of these leaking hulks of aluminum alloy & electronics and the viscosity index of Dexron III, they do not like to shift (operate) in cold weather untill warmed up as this is part of their electronic programing also, this does not happen at idle in these temperatures they need to be driven to further pump the fluid around & warm up.

Theory: #1
Is the leak failure due to cold weather operation? My Logic; Possibly indirectly, seals contract in a cold atmoshpere.

Theory: #2
Leak is in pump area housing. Two lower torque conv. housing bolts known to leak due to "case porosity issues" Remedy; remove bolts, reinstall with two 50CENT copper washers. (Is he a Rapper guy? no two Rapper Guy's)Solution; Allison Factory mandates copper washers into production Sept8/03 forward. Will VIN# disclose Ally build Date? Is date Code stamped on Ally some where?
My Logic; this would have happend long before 155,000+km

Theory: #3
Other pump area Leaks due to any of or combination thereof 10 (countem) converter housing oil pump retaining bolts being under torqued or their afilliated seals damaged or failed. My Logic; 10 Possabilities

Theory: #4
Seal failure/ Fluid pump GM part #29540309 My Logic; seems to be the seal in the overhaul kit that gives up the ghost the most. And yes, make sure trany is in a vertical position upon removal & installation (i.e. TC pointing up.)

Theory: #?? Now I know of missed some so fire away guys:D???
 

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Discussion Starter #2
another BLEEDING Allison

HI Guy's what else should I look for when I drop the trany?
Other than 12 bolts in question and pump seal?
I was going to change fluid, check inner filter, replace outer.
Old fluid looks fresh red & does not smell burnt.
Should i upgrade anything at this time?
Check clutchs, torque converter or pressure switches?
Thanks
 

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I HAVE BEEN TOLD, for waht its worth, that our trucks ahve a samll vent. Too small, if you ahve cold weather, and dotn let the trans warm up properly, ie stone cold truck loaded, you hop in it and give her the go juice, the fluid will expand so rapidly the air cant escape fast enoough, pressure builds up inside the cases and blows seals. Weve had a few trucks at work start blowing seals, and that seems plausible because thats usually how our drivers do it, late, in a hurry jump in and hammer down.
 

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get a high idle installed in your truck for the warm up times to be decreased. if you have steering wheel controls use the bottom left pair of buttons to scroll thru the menu in the dic until you see "elevated idle" displayed and turn it on. truck should idle up automatically when it's cold reducing your warmup time significantly.
 

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only three things i heard was pump seal,the three washers on bottom of bell housing leaking,case porosity.my trans is out now for same reason but was leaking pretty good.now im putting in a stage 3 and 1057 to fix it :D .o and the 15 dollar convertor seal.good luck you may want to upgrade now you dont want to pull the trans out twice.
 

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wawa;1603827; said:
get a high idle installed in your truck for the warm up times to be decreased. if you have steering wheel controls use the bottom left pair of buttons to scroll thru the menu in the dic until you see "elevated idle" displayed and turn it on. truck should idle up automatically when it's cold reducing your warmup time significantly.
They cant when the driver just jumps in and goes.
 

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Before you drop the transmission I would take the truck out after warming it up for a drive and get the fluild up to at least 120 deg. then check the fluid level. If your low then clean things and try to locate the problem before pulling it out. If it's within the proper level then it might be the cold issue the Allison have been knowen to have. A simple fix is to remove the dipstick and see if it does it again. If not then it's vent issue. The vent issue can be solved by drilling a small hole in the dipstick tube just below the seal area of the dipstick itself. The hole needs to only be about 1/16" so do not make it any bigger.
 

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Pull the square inspection cover on the lower left side of the bellhousing and look inside with a flashlight. You will be able to see the lower bolts. many times you will be able to see a trail where the fluid is coming from. Seals on the Alli should not be affected by the weather.
 

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Mike L.;1606705; said:
Pull the square inspection cover on the lower left side of the bellhousing and look inside with a flashlight. You will be able to see the lower bolts. many times you will be able to see a trail where the fluid is coming from. Seals on the Alli should not be affected by the weather.
Thanks for your always informative and correct answer...
 
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