Thread: dexron 6 issues in a 2000 GTP

I dropped my pan 2 weeks ago, old dex3 looked reddish brown, not burnt though. There was a thin layer of junk on the bottom of the pan, and the magnet had a layer of stuff on it too. Replaced the filter, filled it with 7.5 qts of Valvoline Dex 6 full synthetic. Now the car shifts really weird at WOT with performance shift off. The shift from first to second seems to take twice as long as it used to, and same with 2 to 3. At anything lower than 3/4 to WOT, it shifts fine. With performance shift on, all the shifts seem perfect.

Is the dex 6 making my transmission slip? Or are the longer shifts ok for my clutch packs.. if its bad I'm gonna drain it out right away because the last thing I need is a bad transmission.

Oh, forgot to mention, the car has 82,000 miles on it as of today.

You will want to drop the pan again and add Dex 3 to it. Why? Becasue DEX 6 is a synthetic (Thinner) Dex 3 on the other hand is thicker.

Originally Posted by BillBoost37

Most people report that Dex 6 makes their car shift better etc.

Was there a reason behind the service? Fresh fluid of any sort can cause an issue if there's a prexisting item going on. Did the filter fit snugly up into the collar or was it loose? Is the level when running and warmed up at the top mark on the dipstick?

There are some that have good luck with it, and others that dont

Originally Posted by BillBoost37

Right...and just like a trans flush, I'm going to ask the important questions. Of those that had "bad" luck, how many had a prexisiting issue that fresh fluid wouldn't have helped?

Most of the time, we are going to find that people don't maintain a trans very well. Once it has an issue, they try stuff and have "bad luck" with different fluid, a flush, a service etc etc. Yet the real issue isn't the fluid, but instead it's the lack of maintenance to that point.

I did make sure the collar in there wasn't damaged, but it wasn't a super tight fit by any means, just kind of slid in there with little effort. Could fluid getting past the filter be my problem?

And if I do drop the pan again, what brand of Dex 3 should I use? I have 4 qts of Mobil1 Synthetic dex 3 in my garage, do people have good results with that stuff?

The dex 6 did make the car a lot smoother in general, but I'm just concerned about the longer shifts. I tried to make it do the weird shifts this morning however, and it didn't do it. I removed the battery soon after the fluid change, could the PCM still be adjusting?

What's interesting is that the trans shifts fine with performance shift active, according to OP. Something you could try would be to remove battery cables and touching (shorting) the cables together, resetting the learned PCM settings. Then hopefully, the PCM will adjust the pressure to compensate for sloppy shifts.

Its free to try.

After driving it around a bit more, I think the issue was just in my head. The shifts arent exactly sloppy, theres just no jerk at all when the car shifts gears. It was probably just me being used to the feeling of having crappy fluid in there.

I'm just paranoid about transmission issues because everyone seems to have them with these cars.

Give it time, you"ll have them too You'll probably loose OD at some point. Judging by the year you probably have about 120K+ on it so its inevitable.

Just save some $$$ up and get a good rebuild when the time comes.

Originally Posted by FordMan77

Give it time, you"ll have them too You'll probably loose OD at some point. Judging by the year you probably have about 120K+ on it so its inevitable.

Just save some $$$ up and get a good rebuild when the time comes.

83,000 miles actually, guy before me (im the second owner) didnt drive much. When do people start having problems with these transmissions? keep in mind that I don't beat on it at all.

Niiiice, low miles FTW. Well it varies depending on how abused it has been, and the maint. schedule. I would say you could get over 160K+ on it if you keep up with it and don't beat on it everywhere you drive.

That and letting it shuffle between 3rd and OD around 45-47mph will cause the 4th clutch hub to strip and loose OD. I usually keep mine in 3 unless I know I will be above 45 for a while and then I shift it into D while cruising.

Originally Posted by FordMan77

Niiiice, low miles FTW. Well it varies depending on how abused it has been, and the maint. schedule. I would say you could get over 160K+ on it if you keep up with it and don't beat on it everywhere you drive.

That and letting it shuffle between 3rd and OD around 45-47mph will cause the 4th clutch hub to strip and loose OD. I usually keep mine in 3 unless I know I will be above 45 for a while and then I shift it into D while cruising.

Haha thats funny... 90% of my driving is going between 45-50 mph on county roads. My car usually drops into OD with performance shift off at around 40-42ish, so I try not to let it hunt too much. Man I miss driving a manual transmission car. So much simpler

Like the 4-2 downshift and then WOT shifts into OD?

Yeah, you want your PCM to relearn now that the fluid is different. I didn't know you could do this by touching the connections together, I just leave one end off the battery and eat a sandwich. Or use a TechII or something to reset the transmission settings.

So the shifts seemed to work themselves out now, but now I'm getting the "chugging" rpm oscillation when I give it just enough gas to not disengage the torque converter at 40-60. If I press it down past where it does the chugging it gets up and goes, but its just kind of an annoying problem. Fluid is at the correct level and looks brand new.