Strange shifts! Auto! Advice/comments please.

[Red03Mustang]

My car sounds like it is shifting more times than it has gears. I'm driving it normally. Giving it more gas makes the car less likely, or eliminates, it doing this. WOT shifts are excellent, it's only partial throttle, or low RPM shifts that this happens.

I'm pretty sure the 4.10s are causing it, or that the car is doing it because of them. The car never did that before I got those in. I can't tell if the computer needs some tuning, or what exactly is going on.

More symptom details: it only seems to do this in the 2nd to 3rd gear shift. The car will make a noise like it shifted, but it didn't really. It'll hang onto the RPM's for about a second or two more, then it will finally shift to 3rd. It's almost like the transmission hesitates, or like it was going to shift there, or USED to shift there (such as when the stock gears where in) but hangs on a second and THEN shifts.

Also, 3rd to 4rth is not smooth.

Things I've done to sort of even it out, that haven't really worked:
1) Adjust the shift pressures/torque modulation with a Predator tuner
2) Change the transmission fluid
3) Drive it differently, just to see if any particular style suited the tranny more

I've seen someone else on here have similar problem, but they swapped to 3.73 gears and said it went away. I'm thinking the car just doesn't like the steep gears, but I want to keep them in. Any ideas on what I could adjust, or have done to the car to fix this issue? Things I should check, etc.

Things I've heard could be an issue are Torque Converter, and the computer needing a shift point adjustment, which I can't do with the Predator (without sending them the data, anyway).

Any ideas on this would be GREAT, as this has been something that's bugged me for a long time. I'm thinking of trying to find another stang just like mine that's a manual just so I can drive that instead.

 

[03ghoststang]

have you messed around with the partial throttle firmness in the diablo sport??

 

[Kilgore Trout]

When dealing with auto trans always do that which is cheapest and easiest first, in your case do these in this order:

-remove Diablo tune see if problem goes away
-change fluid and filter see if problem goes away
-take it to a transmission shop for estimate

Do the tranny cooler as soon as possible.

 

[triggz]

More than likely what you're feeling is the torque converter locking up. It sounds/feels almost like a shift, and the rpms will drop a bit. This should only be happening just before or just after gearing to OD at cruising speed or WOT.

When you're tapping the throttle, you're changing the computers mind about locking up. (TC lockup only happens at WOT and steady cruising in OD). Plug up your predator and monitor the TC lockup state, watch if it changes as you feel what you're describing.



Try setting your shift firmness back to stock if you've adjusted that as well. The predators adjustment for this seems too harsh IMO and made my shifts feel jerky. It's also possible that theres some damage to the trans/TC causing slippage... but if that were the case it would probably be noticable in all gears though.

You really need to install a cooler ASAP.

 

[kuma]

torque converter lockup schedule needs adjusting at low rpms?

The J-mod will also work wonders on a automatic tranny with gears.

 

[propellerhead]

You have a lot more torque with the new gears. Things will feel different. I can really really notice the converter locking on mine after the 4.10s.

Since you already have a Predator, I would recommend increasing the Part Throttle Shift Pressures, and trying different settings for the Torque Modulation. If you're having issues with it, un-marry/reset the Predator then start over. I've had weird things happen after making many repeated changes over and over again.

If that still doesn't help, I would recommend a custom tune from a Diablosport tuner and have your part throttle shift points adjusted. Runnin' With The Devil has a good program that works great with our cars with 4.10s.

If you didn't have the Predator, I would recommend an Xcalibrator 2. It will allow you to adjust your part throttle shift points.

 

[joshheat25]

I have heard about the J-Mod but how difficult is it to Do? Also Why do you need a different Tranny Cooler you already have one? I feel the same thing it is o/d and it does seem like there is 5 gears!

 

[03ghoststang]

because the tranny is spinning more than when you had the stock gears and heat is one of the problems that would kill an auto tranny, So an aftermarket cooler is recommended to further cool the fluid.

 

[triggz]

I have heard about the J-Mod but how difficult is it to Do? Also Why do you need a different Tranny Cooler you already have one? I feel the same thing it is o/d and it does seem like there is 5 gears!

The j-mod can be performed by anyone who's ever taken apart an automatic trans and worked on a valve body. All that is done is drilling out holes that are already there to slightly larger spec and leaving out the lower springs on the 1-2 and 2-3 accumulator pistons. You can find all the info you need on tccoa.com under their Trans Tech articles.

The stock cooler is more of a regulator. It will heat or [try to] cool the tranny fluid to whatever temp the engine is at (thats up to 220* under normal summer driving). The trans makes a LOT of heat on its own, so its going to see closer to 250 with hard driving if you've got gears and hard shifts. 150-180* is ideal trans temp and will greatly extend its life.

 

[Red03Mustang]

More info.

have you messed around with the partial throttle firmness in the diablo sport??

Yes, I have mine set to:

1-2 = 10
2-3 = 5
3-4 = 5

I set my Torque Modulation to 0% on all, so that i shouldn't have as much 'slip'. This seems to help some.

The Torque Converter lockup doesn't sound like the problem if it only occurs at WOT or Overdrive cruising, because the place I feel the weird "extra" shift most is in the 2-3 shift. Overdrive has a slight "lurch" when it engages, but that's about it.

The weird shift happens if I'm between 2000-3000 RPM. If I under 2000 RPM when it shifts 2-3, that won't happen. Also, if I'm going uphill (hence giving the car more gas), the odd sensation of another gear won't happen on the 2-3 shift either.

It mostly happens on level ground with a shift somewhere between the 2000-3000 RPM range.

Kuma, you said something about adjusting the torque converter lockup schedule at low RPMs. Is this done via computer and a custom tune?

As I said, I'm not sure that is even the problem.

And yes, I do need a tranny cooler, bad.

Do the Predator's full throttle shift points have anything at all to do with the partial throttle shift points in the car's default? I'm wondering if the computer looks at the entire band's availability, and adjusts accross the whole RPM range, including partial throttle shifts, if for example let's say I lowered the full throttle shift points. Just curious about that.

Thanks for all the replies!

 

[propellerhead]

Yes, I have mine set to:

1-2 = 10
2-3 = 5
3-4 = 5

I set my Torque Modulation to 0% on all, so that i shouldn't have as much 'slip'. This seems to help some.

The Torque Converter lockup doesn't sound like the problem if it only occurs at WOT or Overdrive cruising, because the place I feel the weird "extra" shift most is in the 2-3 shift. Overdrive has a slight "lurch" when it engages, but that's about it.

The weird shift happens if I'm between 2000-3000 RPM. If I under 2000 RPM when it shifts 2-3, that won't happen. Also, if I'm going uphill (hence giving the car more gas), the odd sensation of another gear won't happen on the 2-3 shift either.

It mostly happens on level ground with a shift somewhere between the 2000-3000 RPM range.

Kuma, you said something about adjusting the torque converter lockup schedule at low RPMs. Is this done via computer and a custom tune?

As I said, I'm not sure that is even the problem.

And yes, I do need a tranny cooler, bad.

Do the Predator's full throttle shift points have anything at all to do with the partial throttle shift points in the car's default? I'm wondering if the computer looks at the entire band's availability, and adjusts accross the whole RPM range, including partial throttle shifts, if for example let's say I lowered the full throttle shift points. Just curious about that.

Thanks for all the replies!

I had my part throttle firmness at like 45-35-25.

Full throttle shift points don't affect part throttle, unfortunately. That's where the Xcal2 trumped the Predator. They added more options for auto trans, including torque converter lock up schedule adjustments.

 

[03ghoststang]

the full throtle shifts don't affect the part therottle shifts try increasing the part throttle shift firmness see it that will help..

 

[Red03Mustang]

I had my part throttle firmness at like 45-35-25.

Full throttle shift points don't affect part throttle, unfortunately. That's where the Xcal2 trumped the Predator. They added more options for auto trans, including torque converter lock up schedule adjustments.

Guess I can set it up higher and see what happens.

I'll let ya know. Thanks guys.

 

[propellerhead]

You can max them out and still be ok.

 

[Red03Mustang]

You can max them out and still be ok.

OK. I may do that just to go extreme and see if the shifts improve or not, then fine tune from there.

Setting them all up tends to make it shift hard even when I'm giving it just a little gas. Too bad it doesn't have some sort of "variable shift firmness" where it shifts harder the more gas you give it an easier the less gas you give it. I know there are the partial throttle shift firmness and full throttle shift firmness, but I mean adjustments that would look at say, your RPM, and then determine from that how hard to shift. That way you could drive like granny and get a nice smooth easy shift, or drive a little harder and get a firmer shift.

Something like that.

 

[007]

I have a similar experience. After the 4.10s were installed and I immediately switched to the new chip program. Whenever I reset my computer the tq conv locks and unlocks at partial throttle every now and then. It only does it for a few minutes and then learns not to do it again.
It never does it at all unless I reset the cpu. Installing the shift kit had no effect. I believe this may be a chip/programmer issue, since I know my car "learns" not to do it within a few minutes. Wierd huh? I have a mail order Autologic chip from JMS. Do the programmers have updated software you can download. Maybe they fixed some stuff?

 

[Red03Mustang]

I have a similar experience. After the 4.10s were installed and I immediately switched to the new chip program. Whenever I reset my computer the tq conv locks and unlocks at partial throttle every now and then. It only does it for a few minutes and then learns not to do it again.
It never does it at all unless I reset the cpu. Installing the shift kit had no effect. I believe this may be a chip/programmer issue, since I know my car "learns" not to do it within a few minutes. Wierd huh? I have a mail order Autologic chip from JMS. Do the programmers have updated software you can download. Maybe they fixed some stuff?

Yeah, that is weird. My programmer is up to date. I think it's at a custom tuning point, but I sure would've liked it more if the programmer could fix it without having to pay extra $$$.

I know that some autos have some sort of "engage/disengage" mode. I had a Prelude (2002) and it had this. They listed it in the manual. To be honest, I haven't seen that in the Mustang manual. It's possible it could be something like this, but I kind of doubt it.

The car does it regularly in the 2nd to 3rd shift. I almost can't keep it from doing it, unless I start very slowly. I know my car definitely need to hang on to the gears longer before it shifts, and only a custom tune can do that.

Does anyone think this could be something other than the computer needing a tune? If so, I'd love to hear about it. Thanks!