V70 XC AWD L5-2.4L Turbo VIN 56 B5254T (1998)
Transmission Cooler: Customer Interest
A/T - Coolant Contamination Information
Retailer Technical Journal 16724
Coolant contamination in automatic transmissions
If using a printed copy of this Retailer Technical Journal, first check for the latest online version.
THIS DOCUMENT SUPERSEDES THE PREVIOUS VERSION OF RTJ 16724 (TNN 43-48) DATED 4-18-2007. Changes have been made to the
cooler and hose replacement guidelines. PLEASE UPDATE YOUR FILES.
The root cause for some automatic transmission failures is glycol contamination from the engine/transmission cooling system. Severe cases of
contamination are easy to detect by a visual inspection. The transmission fluid will have a milky appearance and there may be signs of transmission fluid
in the coolant reservoir. Less severe cases are impossible to detect without doing a chemical analysis of the transmission fluid. This slight contamination
is easy to overlook and will result in a repeat transmission failure.
A small leak from the cooling system into the transmission can cause driveability problems long before there are any visual signs of contamination.
SYMPTOMS OF COOLANT CONTAMINATION:
The most common symptom of coolant contamination is shudder; a high frequency vibration.
On AW55 transmissions, the shudder normally occurs while in torque converter slipping lock-up mode. It is most easily reproduced by driving
slightly uphill at about 40 MPH (65KPH) in 4th or 5th gear with light pedal at 122°-158°F (50-70°C) transmission oil temperature.
On the GM4T65 transmission, the shudder normally occurs during upshifts.
On all transmissions, other symptoms such as harsh shifts, slipping, flare, loss of drive, other DTCs, etc... are possible but not likely.
The Volvo test kit, PN 30783360, will accurately detect even very low levels of glycol contamination in transmission oil. One test kit contains materials
to perform 25 tests.