What/When Should Be My Next Maintenance?

I've had my 03 Denali for a few weeks now. It has just under 45k miles. I bought because not only was the price right, but it was so clean in & out. I mean CLEAN, you could eat off the inner fenders. Both the diff's are squeaky clean, no drips or leaks. But since I don't know the exact maintenance history of the truck, I wanna go through it to make sure I don't run into any unforseen issues. Any recomendations is appreciated! :thumbsup:

Transmissions build up lots of heat and go through a lot. They aren't cheap to rebuild. I would change the fluid and filter in the tranny. I try to change mine about every 30K-35K miles.
Change the fuel filter.
Brake fluid absorbs moisture. The more moisture in the fluid, the less its effectiveness. And if that is the original fluid, I would look into changing that also. Mileage isn't a concern with brake fluid like time is. The older the fluid, the more contaminated it is with moisture. This should be changed about every two years.
Even without any noticeable symptoms, cleaning the inside of the throttle body isn't a bad idea either. Use some throttle body cleaner on a clean rag and wipe the inside walls of the throttle body. Spray a little around the area of the air bypass passage also. This will help keep it clean and help prevent any idle problems in the future from a dirty TB.

JKmotorsports said:

Transmissions build up lots of heat and go through a lot. They aren't cheap to rebuild. I would change the fluid and filter in the tranny. I try to change mine about every 30K-35K miles.
Change the fuel filter.
Brake fluid absorbs moisture. The more moisture in the fluid, the less its effectiveness. And if that is the original fluid, I would look into changing that also. Mileage isn't a concern with brake fluid like time is. The older the fluid, the more contaminated it is with moisture. This should be changed about every two years.
Even without any noticeable symptoms, cleaning the inside of the throttle body isn't a bad idea either. Use some throttle body cleaner on a clean rag and wipe the inside walls of the throttle body. Spray a little around the area of the air bypass passage also. This will help keep it clean and help prevent any idle problems in the future from a dirty TB.

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Ya my mechanic told me to change the fuel filter pretty often, cause these trucks like to go through fuel pumps. The tranny fluid/filter is a must too. But what about the diff fluid? I was reading the diff fluid should be changed at 50k. But I read a few threads where guys changed there fluid and got a squeal afterwards. That would suck.

Any tips to changing the transmission fluid? Is there a way to flush the torque converter when doing it? I've done it on my F-350 but haven't had any time to look under my wife's Tahoe.

Also, where is the fuel filter located at? Again, haven't had time to really look, but there wasn't a fuel filter listed in the Fram catalog with the oil filters.

Thanks Alot.

I changed my fuel filter and rear diff oil on my 2000 yukon last night. The fuel filter is on the driver side, inline btween the tank and injectors (about middle of truck). The rear diff oil was very easy to change, I used Moble 1 75w-90 Synthetic. No squeels or any noise afterwards. The truck was about a Qt low and very dark, so it needed a change. Im doing the front, and transfer case tonight.

pwrstroker00 said:

Any tips to changing the transmission fluid? Is there a way to flush the torque converter when doing it?

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Here's a way that you can do it yourself without doing any damage to your transmission and without removing the torque converter. You'll need at least two people to do the job, but not because it's that difficult. You just can't be in more than one place at one time.

Here's the plan. Find out how much fluid your transmission holds. Then find out how much fluid your torque converter holds. Add the two together and then add about two quarts to that total. This should be a total of about 13 qts for the 4L60E and 15qts for the 4L80E. You'll probably need the extra to do the job, but if you don't at least you'll have some extra for topping off if it ever becomes necessary.

Now, drain the fluid from the trans pan drain bolt, remove the pan, and change the filter. Once the new filter and pan has been replaced, you must refill it with fresh ATF. Pour in as much ATF fluid as your transmission holds - for a filter change/pan removal, this should be about 5 qts for the 4L60E and just over 7.5 qts for the 4L80E. Once you've topped off the system with new ATF, you're ready to flush the torque converter.

There are going to be two lines which run from your transmission to a cooling system of some sort at the front of your vehicle. This will either be a special section on the bottom of your radiator or a separate transmission fluid cooler. It shouldn't be that difficult to find.

Disconnect one of those two lines. If this line is flexible, then disconnect the end that attaches to your transmission (making sure to clean any dirt off the end of the hose and the area around the connection first). You'll use this disconnected end to drain fluid from. Don't disconnect the other end.

If it is not flexible, you'll probably need to have some extra temporary, flexible hose on hand to use. In this case you'll disconnect the same line, but disconnect it where it comes out of the cooling system, NOT where it attaches to the transmission (again making sure to clean the area around the connection first). Then connect one end of the flexible line (brake line should work - ask your local auto parts store) to the fluid cooler (where you removed the other line) and leave the other end unconnected to drain into a pan.

No matter which way you have to do this, keep in mind that although there might be a small amount of drainage when you first disconnect the hose, it should be minimal and should stop quickly (far less than a half quart). The hose will not drain again until you start the vehicle. If you're not sure you're following, don't worry. It will all become clear.

Now, this is the part where having two people will come in handy. You want to have one person in the vehicle turning it on and off. The other person will be at the front of the vehicle taking care of the draining and filling of the fluid. First comes a little draining.

Have the person up front hold an empty ATF quart bottle with the fluid drain hose in the mouth of the bottle. It will be easiest if the ATF bottle is clear, but it doesn't have to be. As long as you have some way of seeing the fluid level as it rises (you don't want to overfill the bottle and have fluid run all over your hands).

Once someone is in place with the "drain hose" pointed into the "drain bottle", start the vehicle. When the bottle is about full, the person holding the bottle needs to yell to the person in the driver's seat to shut off the vehicle. Once the vehicle is shut off, the hose will stop draining.

Now, you know that one quart of old ATF has been drained. So, have the person at the front of the vehicle, pour one quart of new ATF into the transmission fluid fill tube. Then, you're going to repeat the process. Put an empty quart bottle under the drain tube, have the other person start the car and run it until you fill the bottle again. Once the bottle is full of old ATF, shut off the vehicle and pour in another quart of new ATF.

This process is going to continue until you see a definite color change in the fluid draining from the hose. In other words, what you're looking for is the drain fluid should eventually look exactly the same color as the new ATF you're putting in. When it does, that means you've got the entire system flushed. At that point, you can stop, reconnect the hose and take the vehicle off the ramps. Then, you simply need to check and make sure that you're ATF fluid level is up where it needs to be (and it should be pretty close).

I did that whole process with a explorer. It worked great and it was easy for a newb mech like myself to do. The only thing I did differently was I waited till the fluid was all flushed, then I changed the filter and gasket so I didnt run old fluid through a new filter. You have to use a few more qts of ATF, but your filter is clean for the new fluid.

Also, for the hose, I just cut a old garden hose down to about 5 feet. I just made sure the trans line flowed down into the hose so it didnt come out the top and stain my driveway more than it already is. And it defenetly helps to have two people like JK said.