A/T - Fluid/Oil Leak During Cold Weather
TECHNICALBulletin No.: 10-07-30-001D
Date: February 22, 2013
Subject: Fluid/Oil Leak During Cold Weather from Transmission Vent
Models:
2001-2013 Chevrolet Silverado 2500HD-3500HD Series
2001-2013 GMC Sierra 2500HD-3500HD Series
Equipped with Allison(R) LCT 1000 Automatic Transmission (RPOs M74, MW7)
Supercede:
This bulletin is being revised to add the 2013 model year, update the Important statement and add a Note. Please discard Corporate Bulletin Number 10-07-30-001C (Section 07 - Transmission/Transaxle)
Condition
Some customers may comment on a small red fluid/oil leak during cold weather. Upon further investigation, the technician may find a small fluid leak in the area at the back of the transmission by the vent.
Cause
This condition may be caused by fluid being discharged out the transmission vent due to a low transmission fluid fill. During extreme cold weather, (approximately -25°C (-15°F or colder), low fluid fill can cause the transmission pump to ingest air which can aerate the fluid and push some fluid out the vent.
Correction
On 2001 through 2013 models, verify the transmission is full of fluid. Follow the SI fluid checking procedure to PROPERLY check the transmission fluid level using the Hot Check Procedure.
Important
Ensure that the fluid level is at the top of the HOT band when the transmission fluid temperature is 79°C (175°F). Refer to SI Document ID# 2408059 for the proper fluid level checking procedure.
Note
The fluid level on the indicator may be higher on one side than the other. The lower reading should be considered the actual fluid level. The higher fluid level on the indicator should be considered splash.
Note
Only on 2001-2004 models, replace the transmission fluid indicator (dipstick) with a new vented indicator, P/N 15794381.
Disclaimer