Mercon V in 300d auto tranny
 

I just got a phone call from a friend in Chicago. He bought an '83 300D last week. He was told that the transmission oil and filter were changed about a month before he got the car. The PO said part of a quart was in the trunk. My buddy found a half filled bottle of Castrol Mercon V. He is certain that is what the transmission is filled with. He has not noticed any shifting problems or anything unusual.

Do any of you think the transmission is damaged? Can he change the filter and oil, including the torque converter, and be alright? He says he has put about 200 miles on it. We don't know how many miles the PO put on this oil.

My buddy drained tranny oil (drained converter, too), changed filter and refilled with Mobil 1 Synthetic ATF. He says he notices no difference in shifting, etc. But, he had no compaints about the shifting, etc. with the Mercon V in there. I use the Synthetic and noticed a difference at cold shifts.

Now to see if he has problems in the future.