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2003 Impala Trans fluid level question

I have a 2003 Impala with about 115,000 miles on it. I check the fluids pretty regulary (about twice a month) and I have noticed that my transmission fluid is a tad below the area that has the X pattern that shows where the max level should be. I was wondering should I add some fluid and is it uncommon for a car of mine age wise and milage wise to loose some transmission fluid over time? It’s not a lot that has gone out and not like just recently, I have just noticed over time a slight decrease in it and now it’s below that X pattern area. Also how do I know which type of transmission fluid would be the best to use in this Impala. The engine I think is the 3.1, automatic transmission.

You should add a little. You probably have a very small leak and it might be difficult to find at this time, but do keep an eye on it. You can use either Dexron III or Dexron VI. The III was the OEM fluid but GM recommends using the VI for adding or changing.

Add only a little at a time when the transmission is warm and the engine running (in park). Do not overfill.

If you haven’t changed your ATF, you should consider doing that. No flush, just a drain, replace filter and refill.

I have not had it changed, I bought the car in Dec 2014, and it was changed by the dealership prior to me buying it as I got all the paperwork that was done on the car prior to me buying it. It is a nice pink color to it and was about at the middle of the XXX lineage on the stick when I bought it now 15 months ago. I watch my drive way closely for any signs of any leaks.

Why do you put it in when the engine is running and warm?

It only has to be warmed up when you check it. It doesn’t have to be warmed up when you add it.

A “little bit” is a pint or a half pint at a time, and agree it needs to be warm when checking. Those pan bolts can loosen up over time and cause some leakage. A lot of times the trans shops want you to come back after 30 days so they can check for leaks, so its not uncommon.

Check the transmission fluid level when warm? Absolutely not. This is one reason late model vehicles do not have transmission dipsticks, do-it-yourself owners overfill their transmissions. If you add transmission fluid when the transmission is warm, (after 3-4 miles of driving) the transmission will be overfilled.

Transmissions on late model vehicles are checked when warm, 105 to 130 F. This older vehicle is to be checked when the transmission is hot, about 5 miles of driving after the engine has reached operating temperature.

From the owners manual;

To get the right reading, the fluid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C). If it’s colder than 50°F (lO°C), you may have to
drive longer.

Don’t confuse engine temperature with transmission temperature, they don’t warm at the same rate.
Check your transmission fluid level after you get home from work.

As for where the fluid is going, I presume you see no leaks under the car. Then you might have a tiny amount leaking from the pan gasket. But it is so small it isn’t leaking on the ground, but just blowing away as you drive. One idea, if getting to the bottom of the fluid loss is your objective, ask your shop to check the torque on the pan gasket bolts. There are probably some sensors and solenoids that screw into the case that could have a small leak too.

Another idea, there’s a pump inside the transmission that forces fluid around to various places inside under pressure. That pressure is used to push on various gadgets, usually against a spring inside a tube, and some of those gadgets – like the transmission clutch packs – can wear with time. That wear reduces the dimensions of the gadgets and creates some extra volume in the fluid path, similar to how the brake master cylinder fluid goes down over time even though there’s no fluid at all leaking out.

If the transmission has never had a proper service – drop the pan, change the filter – at 115 k miles, now would be a good time. Ask at your Chevy dealer parts department which transmission fluid to use. Tell them your VIN and they should be able to tell you the proper fluid straight away. They’ll probably have some in stock to sell you. Often dealerships sell transmission fluid for about the same price as other stores for some reason.

The whole point of adding any fluid…or even checking the level … when the transmission is at operating temp, is so as you add fluid you can then check the level again and add more if needed.
If you add fluid to a transmission without it being at operating temperature you may over fill it before you realize it.

But as said by others, you should have the fluid changed and filter replaced. It will give you a longer life to the transmission.

If you change this out yourself, just drop the pan and drain the fluid into a drain pan. Then just pour the old fluid into some old milk jugs to dispose of (many auto parts stores take old fluid).
With it in jugs you can get a pretty close idea of how many quarts you need to add.
Also any good auto parts store will have data on the amount you need for a drain and fill.


Another transmission service this soon should be unnecessary, transmission services are recommended every 50,000 miles with severe service.

I always check my trans fluid after driving the car for a decent amount of time to make sure the transmission is warmed up. The fluid was changed out by the dealership at 103,000 and it’s now at 115,600, so don’t think I should need to do it again so soon.

One other possible leakage/seepage point is along the fluid lines that connect the transmission with its cooler (which might inside the radiator, or separate from it.) I found these connected with small hose clamps on one of my vans, and tightening up the clamps eliminated small leaks.

Nevada, when I say warm, I mean normal operating temperature. A lot of us do that. To me, Hot means overheated or very close to overheated.

Most temp gauges have the normal operating temp somewhere in the middle range of the gauge. Cold is to the left or most CCW and the red zone or hot zone is to the right or most CW, so the middle is “warmed up”.