Ahh.. I have two vehicles and got my tachs confused with one another. I meant redline, so, 6k it is.

I rarely ever beat on it. Was just doing some tests recently.

Today I started it cold and pulled the dipstick out and there was barely anything on the bottom (definitely not within range). I went ahead and put half a quart in. Im going to wait a couple hours for all the fluid in the dipstick line to drain down, then reevaluate if it needs more, which more than likely will.

 

I believe you are supposed to drive it for a bit (at least 10 minutes should be good) and then check your dipstick. Make sure you don't overfill. That's no good either.

 

OK on the tach but still why if you noticed it slipping 2 months ago would you not immediately check the fluid level? Running the engine up over 5K may not be what you consider beating but it's definitely running one of these trucks hard which in turn is rough on the trans. The trans in the 2003-2007 trucks is kind of a weak link so it's something you want to address right away.


As madmayo states..... drive the truck around a bit, do this without pounding on it. Park the truck on a level surface with it running, wait a couple of minutes and check the fluid level, you may have to wipe the dipstick and re-insert it a few times to get an accurate reading as fluid can work it's way up the tube and give a false reading the first time. If it's still low, add accordingly and recheck until the level is satisfactory. I will also second the statement that you definitely do not want to overfill it.

 

Ok guys, heres an update.

Went to GMC and picked up two quarts of ATF fluid. Came home, poured in half a quart.

Three hours later, I decided to go drive around and warm it up, taking it easy. I drove about 17 miles across an hours worth of time and the tranny was nice and warmed up.

I left the vehicle running while I checked the fluid (as per the service manual instructions) and the dipstick showed barely a drop on the 'cold' setting.

(I also tested it with the vehicle off and it was about 2mm below the 'hot' setting)

What do you guys think? Low about 2 quarts? I plan to put another 1/2 quart in now and resume checking it tomorrow.

 

Ignore the measurement with the vehicle off. It needs to be idling.

So I'm a little confused. Did you just add half a quart total so far?

And are you saying that your measurement after you added fluid is lower than your initial measurement with trans warm?

If so. You need to be asking yourself where it's going?

Do you see any red drops where you park?

Smell burning oil while driving?

Check bottom of pan, bellhousing, output seal, and especially hoses / lines to rad.

 

Id be wondering where the trannie fluid is going also? even when you do have it filled to proper level (make sure you don't overfill) keep checking constantly sounds like a you may have a bigger problem might want to check your trannie filter might find some sludge in there. Ya might want to carry an extra quart or two keep on hand. good luck and learn from this experience hopefully you will get lucky

 

Sorry for the confusing post.

Basically, I added 1/2 quart, drove around until warm, checked it while idling, and it was extremely low. The fluid was still on the 'cold' setting, and only about a drop worth. (This was after driving 17 miles over an hours worth of time...plenty of time for the tranny to be warm.)

After seeing this, I filled up another 1 quart. (for a total of 1.5 quarts all together today). I tried checking it but the fluid was still running down the dipstick tube after 5 minutes of waiting around. I went ahead and gave up for the day because I had dinner plans. Drove the H2 to dinner and didn't see any slipping but it was only about a mile drive there. I will continue this process on Monday.

The last known service was around 75-80k miles and it has 130k miles now. I will get under the truck next week and see if I notice signs of leakage.

 

Just an update.

Driven the h2 about 25 miles since putting in 1.5 quarts of tranny fluid. So far, no noticeable slipping has occurred. Actually, this is the best it's felt in 6 months.

 

Sounds like your tranny has high milage and wouldn't be surprised if a transmission failure is on the horizon. I could be completely wrong, but I just had a new transmission put in mine. First symptoms were light slipping. Then my dipstick kept giving strange levels of fluid.

Do you have the stock tranny cooler?

 

I believe everything is stock. I will continue checking the fluid this week and make corrections if necessary.