My transmission slips when in going forward, however, it doesn’t when in reverse. Also, the transmission fluid is brown. What’s wrong?

The simple answer is that the brown transmission fluid is either very old or has been exposed to extreme heat conditions, both of which are predictors of impending transmission failure. The more complex answer is that you need to have the transmission evaluated by a competent transmission shop in order to get a more specific diagnosis and a cost estimate. And, you should be aware that the word “competent” is not normally used in the same sentence with names such as AAMCO, Lee Myles, Cottman, or any other chain transmission operation.

A good independent transmission shop can tell you whether the transmission may be salvageable with just a fluid and filter change, or whether it needs to be overhauled. A chain transmision shop will definitely tell you that you need an overhaul and will then overcharge you for substandard work.

Incidentally, if you will post back with details such as make, model, odometer mileage, model year, and the date and odometer mileage of the car’s last transmission fluid change (probably never, I assume), then you can receive more specific advice. Right now, your question is similar to telling a physician that you have a fever, and asking for a diagnosis based on that scant information.

Any malfuntion in a transmission is a bad sign. If the fuid is brown, it is burned from excessive internal heat caused by slipping bands, among things.

You should IMMEDIATELY take it to a good independent (not a chain) transmisssion shop and have them evalute it. You have not given us the make and mileage or if the trasmission was ever serviced. In your case it is a case of either ABUSE or NEGLECT OR BOTH!

If you are lucky, it will only need a fluid and filter change with an adjustment. About $100 or so. Most likely you will need a partial rebuild at $600 plus, going to $3000 for certain imports.

That $100 service every 40,000 miles is a real bargain; folks that do it get at least 250,000 miles out of their transmissions.

Unfortunately, with the brown fluid and the fact you slip in forward gears, you are looking at an overhaul. If it slips in forward but not in reverse, all that means is that the forward clutches are burned up. I wouldnt waste any money on a fluid and filter change. I would be considering an overhaul. What kind of vehicle are we talking about??? Make, Model, and engine size would help.