Quote:
Originally Posted by Overboost
Well I think I have come up with a game plan for servicing my 3.0L GM A5S390R (GM 5L40-E) with 180,000 miles without a transmission service ever, at least for now unless I find some crystal ball that will predict the outcome of the transmission fluid and filter change.
I think what makes sense to me is to crack the fill plug when the system is cold and gather a few drops of the oil and determine the color (and health) of the oil. Basically see if it is red, dark red or black.
- red oil would indicate it is probably a safe move to changing the transmission fluid and filter
- dark red oil would be fair to drop 1/2 the oil through the drain plug and top off with fresh fluid leaving pan and filter intact and re-evaluate after 5,000 miles
- black oil would be a sign to tighten the plug back up and continue on borrowed time
Any other thoughts or suggestions from our specialists or speculists? |
In these GM boxes original Texaco oil from factory is brown not red.
Why not change the whole oil content by flushing?
The main culprit on these boxes is torque converter lock up clutch wearing out. After the clutch material is worn out metal shavings will do the rest. For my E39 530d with the same GM box I renewed the torque converter as preventative maintenance after 300t km. Oil and filter changed by flushing every 120t km. Now 400t km on the clock with no problems.