We have a 95 Ford Taurus with a V6 and an automatic transmission that just recently started having some problems. It all of a sudden began having difficulties sitting at idle and accelerating from a stop. It feels like when you’re driving a manual and you don’t give it quite enough gas. It has no problems shifting from first to second or into any other gears. Reverse is fine, and if you put it in neutral while stopped it does fine as well. We checked everything out, the only abnormality is that the transmission fluid is burnt. I’ve been told by a local mechanic that they can’t flush the transmission due to high mileage (~176k) and that it would do us no good to change the fluid.
My questions are:
Is this likely to be something related to the transmission fluid?
It may not be the transmission. It could be bad fuel injectors, dirty fuel filter, vacuum leak or some other problem with the fuel/air/spark combination that makes the engine run.
If it runs fine in neutral but struggles when you put it in gear, that can be a symptom of a vacuum leak. It’s a lot cheaper to fix than a transmission, but it can frustrate the hell out of the mechanic to find it.
When’s the last time you changed the air filter and had the spark plugs inspected? If your car is 10 years old, there’s likely a lot of things that need to be cleaned out or replaced.
I agree that the symptoms – idles rough in gear, rough and lacking power on acceleration – sound like an engine performance problem, not a transmission problem. The point is these are conditions where some load is put on the engine, whereas in neutral there is no load. Of course it has to be in gear for the symptoms to appear, but being in gear isn’t causing the problem, merely illustrating it.
The problem could be in the ignition system, fuel system, or electronic engine control system. Spark plugs and spark plug wires are a good place to start, but there are lots of other possibilities as well. A competent repair shop can find and fix the problem.
EGR valve stuck partially open is a good possibility…assuming it has one…only Ford that new I’ve worked on is a diesel. Fuel pressure regulator failure could be another possibility.
Go to autozone and see if they can read the trouble codes for you. (It’s free) 95 is kind of a transition year between the old, stupid simple, way to report codes, (EEC-n) and the newer, gee-whiz, stuff (OBD-II) so don’t be to supprised if they can’t.
Even though it’s probably not the problem, you definitely should change the transmission fluid if it’s burnt. If you don’t, the clutches will start slipping and will wear out quickly. I’ve even had mine start jerking, I believe because the torque convertor pump was having a hard time with the thick oil. Change the oil and the filter or prepare for a rebuild.
It depends how burnt. Dark red, orange, yellow, even brown fluid is usually safe to change. If it’s black, it’s a virtual certainty that fresh fluid will push the (already badly worn) transmission over the edge and cause it to fail now rather than later.
Out of curiosity, how can burnt fluid help a worn transmission? All I know of that happens to the fluid is the viscosity rises and the friction modifier burns up and I can’t imagine either being beneficial for any transmission. I’m sure I’m missing something.
I’m not sure I understand the question. I didn’t say burnt fluid helps a transmission, and it doesn’t.
What I was saying, was that in cases where the fluid is badly burnt (typically black), the transmission has significant internal wear and is to some degree on its last legs. Fresh fluid with its aggressive detergent additives will clean out some of the varnish that’s helping seal some internal passages, and those “last legs” will get kicked out from under it. A typical scenario is the car is driven into the shop, the severely deteriorated fluid is changed for fresh fluid, and the car won’t drive out of the shop. Overhaul time.
Rather than worn fluid helping a worn transmission, it’s more like fresh fluid hurting it. Keep in mind this doesn’t apply to moderate wear, and generally a fluid change does some good, certainly no harm. Regular fluid changes are good maintenance. It’s in those cases where maintenance has been neglected for way, way too long that a fluid change is inadvisable.
The viscosity isn’t the problem, although the wrong viscosity in a transmission can’t be a good thing.
The problem is having a delicate, crud-encrusted system that is basically working, and then dumping detergents into the system.
At that point, your caked up crud may flake off of where it was and wind up in some of the more sensitive areas of the transmission. Enough of this freshly released sludge may cause your tranny to go downhill.
This is why, if you’ve gone around 80K to 120K without changing your fluid, garages will tend to refuse to change your fluid.