Allison hit the ditch / Generals Answer

[Onebigcanuck]

Engineering inform us "fluid can become back and severly burnt from extended periods of in gear idling"

I agree but as this condition hasn't happened, what made mine do it.

Perhaps bad fluid ???

2 others have had same complant in last 4 days and this is from a small dealer.

:confused:

[More Power]

I've sent a note to Allison regarding this thread. Hopefully, they'll be able to give us more info....

MP

[More Power]

Allison responds:

"Is there a chance you can get the V.I.N. for this truck? Also, the mileage would be helpful. According to a previous thread, the owner experienced a high pitched noise prior to checking the trans fluid and finding it black and full of shiny "stuff". Kind of makes me wonder if the unit might have a mis-assembly issue just now surfacing or a torque converter failing.
Allison"

Please send your VIN to my email address is you're concerned about posting it in this thread.

MP

[Onebigcanuck]

More power, I've sent an e-mail to you at: turbo@TheDieselPage.com

[More Power]

Your info has been sent to one of the Allison engineers who works with GM-TAC, to help dealerships resolve customer concerns. I'll post what they have to say as soon as I receive their reply.

MP

[dmaxalliTech]

Just some added info on this. GM has a PI concerning what sounds like your issue. Here is the overview below. I have had a few trucks in with fluid so bad I was sure that it had trans problems. Trucks drove fine and no codes. I replaced both filters and thorougly flushed the trans/coolers. Used Dex III in both cases and no problems have occured after that. Seems no ill effects yet.

Allison LCT1000 Dark or Discolored Transmission Fluid with No Loss of Performance - kw automatic black fluid GMT800 oil repeat #PI01932 - (Mar 30, 2004

Chevrolet Silverado and GMC Sierra trucks equipped with the Allison LCT1000 automatic transmission may experience a condition in the which the transmission fluid has become dark/discolored (dark brown to black). There will not be any transmission performance issues with the transmission.

Recommendation/Instructions:
Testing performed by Allison Transmission indicates that this symptom shows a degree of viscosity breakdown of the Automatic Transmission Fluid (ATF). Viscosity breakdown occurs with vehicle usage, and occurs more rapidly with increased loads and heat. If this condition is encountered, the ATF and external spin-on ATF filter should be replaced and the transmission oil cooler lines and coolers should be flushed. Additional trucks used for towing or hauling should utilize the Tow/Haul Mode when the gross combined weight is 75% of the vehicles gross combined weight rating. The

[Onebigcanuck]

Any news from our friends at Allison ????

smile.gif

[More Power]

I received a note from Allison about an hour ago. In a previous email exchange with Allison, they requested some additional info from Bill.

Here's what I sent Allison:
-----------------------------------
Bill reports:

1GTJK39113E11xxxx

The truck has 35,000 kms on it. They also did a test on the pump and the pressure was down while under load. They completely disassembled the unit and everything looked good, plates, bearings etc. Since replacing the fluid the noise is gone.

Just by way of interest I clean between all the rads twice a year and the trans temp gauge has never been above 95C even while towing up a 8% grade for 6 miles coming out of Lewiston, ID.

The trans filter was changed at 5,000 km.
Bill
--------------------------------------

Allison responded:

Jim,
The response you received from Bill leads me to believe that the unit is now functioning properly and has no problems. In one of the postings, there was a response from dmaxalliTech which may have hit the issue on the head. As far as the noise Bill previously encountered, I can only speculate that it might have been due to the de-graded fluid or the filter bypassing. Looking at the past warranty service claims on the truck didn't show anything that might be related to the most recent experience.