What dictates the quality of the shifting?
 

Hi everyone. My trans has been shifting funny lately. Like more firm and when I let off the gas, it takes a second to change gears again. The fluid is pink and is not even a year/10,000 miles old, but it has a bit of black dust in it that was stuck to the dipstick (If I let it go for a few days to a week, there is more on there compared to if I check the fluid daily). It has along with the radiator cooler a B&M cooler and a 1/2 qt of Lucas in the fluid. I don't think it is slipping. Before when I was going up a slight incline, it didn't want to go into 3rd. Weird, but it went into 3rd a couple minutes later just fine. The truck has a new TPS and there are no codes. What variables dictate how a transmission shifts? Sometimes this thing shifts hard, sometimes I can't feel the shifts. It also depends on which gear it is going into.

Is your fluid level going down at all?

Not at all. To my knowledge, this trans doesn't leak. Haven't had to add fluid to it at all.

Is it possible that it is running too cold? Can transmissions run too cool that they have problems operating? I held my IR thermometer to the cooler earlier and it was only around 85 degrees. Just hot enough to feel hot to freezing hands when I reach through the grille and touch the bottom where the lines go into it. Normally it is between 100-140 (little more if I am in the mountains) and just hot enough to touch, but not so much that it is too uncomfortable or burns. I learned that what it is at the cooler is normally what it is at the pan or the cooler line.

hmmmm...thats a little cool....most of my cars ran around 175-190. i dont think thats the issue though.....black dust? eh. not sure what that can be,maybe clutch particles..Didnt you just have this rebuilt again?

Never been rebuilt. Original trans. Always been some dust in the fluid, but it looks like there is a little more than usual, especially if I haven't checked it in a while. It is like it is on the dipstick, but the fluid itself looks fine.

The truck also has a deep pan and the mechanic transplanted the original magnet to the new pan and I also had a magnetic drain plug put in. Seems like max thermal and particle protection I can add to a trans on a budget. Deep pan, cooler and magnetic plug.

ahh Therandom1 had the trans rebuilt. your pic looks similar and i was thinking about his blazer..

Pour half a bottle of lucas trans flush in it. then let it idle for 30 min then take it for a drive for a bit and check the fluid...if it gets really dark/brown,you just have a dirty trans. If its dirty then,have a flush done.

Trans flush? Lucas makes a trans flush product? Don't flushes and solvents do damage? I had a fluid change done 11/2007 just after I got the truck at 58k (pan was dropped to replace pressure control solenoid due to bone-shattering shifting. That wasn't it. It was a loose connector on the PCM. $1000 out the door to GMC), flush done 2/2009 (plus filter) and 2/2010 (not with filter) and then had the fluid changed again 12/2010 (plus filter). On average, I have the fluid changed or flushed every 14k and the filter every other change (if it was a flush, but any time the pan is dropped, I have it changed). How could I have a dirty trans if the fluid is changed very often? Could there be any other issue outside the trans? Did GMC release a software update for the trans since 1998? I am an IT student and I realize that updates can fix the weirdest of problems.

holy batman the flushes! lol. i doubt its that then..but yea lucas makes a flush product. What im worried about is the black stuff on the stick. something insides getting eat up. im not sure about the updates,everything i have is from early 90's.

Since I continuously monitor the health of major components on the truck (one way is checking condition of the fluids), I keep a photo record of the condition of the trans fluid. Mainly, it seems that if I don't check it for more than a few days, more dust appears and it is stuck to the dipstick. But in the past, the dust situation is the same way with samples.

See attached. 3 random samples from the month of October, 1 from August and 1 from June. The stain on the paper towel with the most dust is the first one, ones without it are subsequent ones. The ones in August and June don't have much dust, but this was when I checked it almost every day and there was no chance of significant accumulation. But you can see that the color of the fluid has not changed at all.

I found photos from August 2010.