2003 auto GT - Shifts seem too rough, could use some of your thoughts.

[Red03Mustang]

Hey guys. Got a transmission question for you.

I have 4.10 gears in my auto GT, 2003. Even though I have programmed my car with a Diablosport predator, the car seems to act like it still wants the 3.27 gears. What I mean is, even though the speedometer is calibrated, the rest of the shifting process doesn't seem to accept the shift change like I expected it to. The car will jerk more on shifts, plus it shifts into overdrive pretty hard on a regular basis.

Is there anything I can do to help my shift be more smooth? I have already set the shift pressures back to Stock on the predator tune. I prefer a smooth shift over a hard shift.

Also, this isn't related (that I know of) but my car has been having a harder time starting lately, and sometimes when I first take it out of the driveway it acts like it is going to die when it hits end of first/first of second gear. Then all is well after that. Any ideas? I have a stock air intake (prefer it over anything else actually) and just 4.10s, catted x-pipe and Magnaflow exhaust.

I bought 3.27 gears to put back in the car since I'm eating some gas with the 4.10s, plus I prefer the smoother shifts. Does this seem like a good idea, or is there something else I should check?

Thanks!

 

[2001sleeper]

the shifting is dealt with in your tune.

 

[blksgrl]

Tuned mine yesterday and had some issues at first because we set it for 3.73 gears, but it didn't react right so we just kept altering the shift point until it was back to normal! My car was also doing the same thing when I'd start it...I'd put it into gear and it would almost feel like it was going to die...changed the plugs and cleaned the MAF...today it seems to be runnin perfect again

 

[rjstaaf]

There is more than one setting that affect the auto.

# WOT Shift Pressure
# Part throttle shift firmness
# RPM Shift Points
# Torque Modulation (for better shift feel)

Not that familiar with the Predator. Can you just change the gear ratio on the stock tune without uploading a performance tune? If so, that is what I would try.

Also, just to hit the basics, have you double checked the fluid level in the tranny? If the fluid is low that would cause shifting problems.

 

[Red03Mustang]

There is more than one setting that affect the auto.

# WOT Shift Pressure
# Part throttle shift firmness
# RPM Shift Points
# Torque Modulation (for better shift feel)

Not that familiar with the Predator. Can you just change the gear ratio on the stock tune without uploading a performance tune? If so, that is what I would try.

Also, just to hit the basics, have you double checked the fluid level in the tranny? If the fluid is low that would cause shifting problems.

Yes, I have checked all of those. I've set my shift pressures all to Stock. Now, I did leave my RPM Shift Points at what the predator tune sets them, which I assumed is stock because it doesn't seem any different when driving. I could be wrong. But, I'm not hitting those shifts unless I go WOT, which I am talking about daily driving shift really. So that should be under the part-throttle category, which those are all set back to stock. Also, Torque Modulation is set to 0%, or none.

Thanks for the input so far. Anyone else have any ideas? Thanks!

 

[propellerhead]

Also, Torque Modulation is set to 0%, or none.

0% means it won't modulate the torque during the shift. This means it will NOT pull back the timing during the shift, like the factory tune does. Torque Modulation at 100% means the EEC will pull back the timing during the shift so you won't have the full torque as it engages the next gear, which means the shift will be smoother. 50% means it will do it but half ass.

 

[Red35th]

The problem is that you are now at a different point in the rpm band at the shifts. At part throttle the stock tranny shifts are done using the TPS and mph.

The stock settings short shifted bad enough, I had to push mine back a few mph to help this. I would guess that you are using more throttle now due to the gears, that along with being at a different rpm per mph has resulted in harsher shifts. The shift pressure is also determined by the TPS. Now you are higher in the rpm band and using more throttle for each shift, even though it is coming at 12-15-32 mph accordingly

So in short, either the tune automatically firmed shifts across the board or it is the result of the gears. If you can adjust the part throttle shifts with the Predator try lowering the mph of the shifts a little. (This answer is way to long, it's prob just the predator tune).

 

[95CobraStang]

Thats not right. 1= all torque available.... 0= much less

-from the manual

0% means it won't modulate the torque during the shift. This means it will NOT pull back the timing during the shift, like the factory tune does. Torque Modulation at 100% means the EEC will pull back the timing during the shift so you won't have the full torque as it engages the next gear, which means the shift will be smoother. 50% means it will do it but half ass.

 

[Red03Mustang]

thanks for the replies

Thats not right. 1= all torque available.... 0= much less

-from the manual

That's what I was thinking.

Thanks for your thoughts guys. I'm trying to figure out what I should do at this point. I have the option of trading my current '03 GT for an '05 V6. I would miss the loss in power, but to be honest, I don't think I'd miss it that much. I don't use it a whole lot as it is, especially since I am more than likely going back to the 3.27 gears with my current car as it is.

I think an '05 V6 Manual would be a lot of fun, plus be a better car. But, I do like my '03 a lot, and a V8 is great. I've just never really gotten along with the auto's shifting, even though I can live with it. Plus the rattles that come with these models drive me crazy. A friend told me he read an article that said with the '05 models they have fixed most of the rattles and squeaks that the previous models had. If that is true, that's worth a lot to me. It makes the car seem more solid and quality-built.

I can never make up my mind.