When to change transmission fluid
Q. My 2005 Chevy Cobalt has 70,000 miles on it I am thinking of changing the transmission fluid. Is it necessary at this time? How much should I expect to pay?
I received quotes that ranged from $90 to almost $200. What is this Dextron 8? I was told it is very expensive. Should I also be changing the filter or is that part of the service. Also, where is the transmission dip stick on this car? After calling around I had one transmission shop tell me not to do anything. What gives?
A. The best thing you can do to prolong the life of a transmission is to keep the trans fluid clean. I recommend changing it every 30,000 miles. If it has not been done on your vehicle yet, I would consider changing the filter and also doing a fluid exchange. The next time you do it, at 100,000 miles, you can just do the fluid exchange.
A fluid exchange with the Dextron VI is in the $160 range. A filter and gasket change is in the $100 range. I do not believe your car has a dipstick to check the level. I only recommend caution in changing the fluid when the car has a lot of miles on it and the fluid is black because it has never been changed. Sometimes in this case the new fluid (which is highly detergent) can clean things up so good that the car will no longer move. I can't imagine at 70,000 miles your fluid is that dirty.
Q. Our 2000 Mercury Sable has 83,000 miles and has been meticulously maintained. It performs like a new car, but has one problem. The windshield wipers will not go on in the winter when the temperature goes down to 32 degrees or below. The problem began about three years ago. We've had our Ford dealer and several other mechanics try to analyze and identify the problem. No one has been able to figure this out.
In addition, when the repair people bring our car in their garage to do the work, the wipers go on! The service people then tell us they can't find a problem with the wipers and send us away with wipers that still do not work. We are in desperate need of your help.
A. We have not seen this particular problem in the shop, but it sounds like a possible wiper motor problem. Have you ever left the car overnight at any of the shops you have worked with? If I were presented with this problem I would want to leave it out overnight on a cold night to see what the wipers do in the morning. I did notice there was a recall listed for some of the 2000 models depending on when they were built. Maybe your car falls under this wiper motor recall.
Q. I recently purchased a 2007 Sienna Limited AWD with 70,000 miles and have some issues with rattling on the floor near the driver's door and the driver's seat. Since your column about another Sienna with a similar problem, has Toyota pinpointed the issue? I have a three-month warranty and seven days to return vehicle. I would love to present technicians with your answer.
A. We actually traced the vibration on the other Sienna to a bad motor mount. However, the client got a different car before we had a chance to replace the mount so I can't say with 100 percent authority that it was the fix, although we were pretty confident.
We were able to duplicate the vibration with the car up in the air and make the vibration go away by taking the load off one of the motor mounts. I don't know if this is the same issue as what you are dealing with but it might be a good place to start.
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