Question for the Mad Dr.
 

Or for the Mad Dr. Jr. (that would be you Jack and Janet)... You know how our trucks reduce power when you manually shift to 2nd or 1st? Can that be programmed to go away with a custom tune? It's really annoying. Is there any other way to override this feature?

I don't understand what you're asking here. Are you talking about the "lurch" down that you feel when you downshift using the lever, but haven't increased the gas yet? I know, with a manual, it's easy to feed in the gas full as you let out on the clutch after a downshift so that the power is immediate, but it's not so easy to time it right with an automatic. I can't imagine there'd be any way to eliminate the lurch, but, maybe I'm wrong.

I think though, you could force a 3-2 downshift by stepping on the gas and then, once it's in the new gear, just drop the shifter into 2nd to keep it there. That would avoid any loss of power.

And, you could do the same thing from 2-1.

Oh, and thanks for the "Jr" title. It feels like an honor (totally undeserved).

- Jack

I think hes talking about when you put it in 2nd or 1st from a dead stop it is not as responsive compared to D.

If you put it in 2nd gear, it stays in 2nd gear...all the time. That includes when you start from a dead stop.

I know. I think he was wondering if you could customize one gear.

When it is put into any other gear than d, an electric bypass of the fluid in the transmission happens. It rather an extensive technical issue the way the tranny is set up like this. My understanding is that it allows for more continuous power with out allowing the torque convertor to lock up at all. It operates like an old power glide at this point.

They probably did this so if you are probably stuck. Its easier on the tranny and power train. I really don't think they engineered it to be used this way on hard surfaced roads.

When in 2nd mine does shift up from 1st.

Lars

It's useful in an uphill climb where the power requirements keep causing a shift in and out of 3rd to 2nd. Better just to stay in 2nd. I would not have thought though, that the converter would not lock if the power demand stabilized. I'll have to test this. If it doesn't lock, why do we have lock/unlock adjustments for 1st and 2nd gears?

I think you're right about shifting up from 1st into 2nd though if the stick is put in the 2nd gear position. But again, I need to try this to see for sure. If so, it's too bad, since it keeps you from using the old start in 2nd trick to keep from losing traction on very slippery surfaces.

- Jack

One of the reasons the tranny does this is at normal d driving you are getting enough air to keep everything cool.

The lock up feature on the tc locks fluid in in there at normal driving. Now if it locks fluid in there you have less fluid to use to cool the system. Now if towing really heavy loads its recommend to turn off the od and essentially that turns the lock up off. Thus allowing for more fluid to cool.

The lock up feature is also used when in d for the other gears also kind of acts like a half gear sometimes.
So by putting into 2nd you are telling it to shut off the lock up and not going to be driving in normal conditions. I do not know if the gryphon can be tuned to change this.

Yes Jack I to use the gears to get out of slippery situations too.

Lars

That is an incorrect statement.

Towing with the OD off allows the tranny TO lock up the TC so that it does in fact run cooler. Towing with the OD on, (in most cases), will have the truck running in 4th gear with the TC unlocked and causing a large amount of unwanted heat.

Yes I was wrong!

Turning off the od will eliminate the back and forth shifts from 4th to 3rd, 3rd to 4th, but not the lock up.

Once again I apologize "put the cart before the horse"

Thanx for the correction.

Lars

Yes, thats what I'm talking about. I read somewhere that it designed to be used in slippery conditions or when pulling a boat out of the water to reduce tire spinnage (i dont think spinnage is a real word but it sounds good, opposite of spinnage would be grippage:cheesy smile:) Anyway, I notice a big reduction in power if I manually take off in 2nd or 1st. Try this next time you hop in the pickup, shift to 2nd and accelerate, then shift up to D. To me it feels real sluggish until I upshift, then the power comes back. I'll have to check the comm gear to see if it's going back to first, but I dont think thats it. I'm wondering if that can be programmed to go away. Incendentally, all four of my Fords (05f150, 88f250, 87motorhome, 67 Mustang) will start and stay in 2nd if manually shifted there. None of them will start in 1st when starting out manually shifted to 2nd. Sorry for the longwindedness.

I was actually having a bit of trouble with several points in this thread, but I decided to wait just a bit before coming back in.

Isn't it the case that when the torque converter is unlocked, it acts as a torque multiplier? (Since it allows the engine to rev at a higher RPM where it has more power to deliver).

And, my somewhat limited understanding of torque converters suggests to me that if they are unlocked, they generate a lot of heat - that energy coupling through the fluid has to go somewhere. But, if the converter is locked, then it is really doing nothing (relatively speaking) so it's not producing heat at all.

Isn't it the case that there is the least amount of wear on the powertrain if the transmission stays in one gear and the torque converter stays locked?

- Jack

As I said before, when you put your truck in 2nd gear it stays in that gear ALL the time.

So, if you are at a dead stop, put it in 2nd and then proceed to take off, you are starting in 2nd gear - which will feel like there is a reduction in "power" off the line.

When towing heavier loads, you still need to be aware of what the TC is doing. Even with OD off, your truck can still lock and unlock the TC and have heat problems. I always have Comm Gear and TFT Temp on my Gryphon and look at it way more than my speedo or any other gauge when towing.

My driving habits when towing have really improved since my Gryphon purchase and I'm sure my truck thanks me.

:thumbs up yellow:

These are good points, RED4. We're going to tow our trailer up to Sedona in two days. I'm monitoring the gears and TFT now and it will be interesting to see what happens. There are some long hill climbs on this route.

- Jack

After further research and trial by error my ford f150 stays in second.
OD and 3 speed trannies have a built in feature that locks first and second gears together by the use of the torque bands. In manual tranny terms like starting out in second gear with feathering the clutch.
However on the way home in the gmc while from a dead stop put it in second and stayed in second. Did this again with trailer mode on and had a 1-2 shift. Retried same results. The gmc has the 5 speed auto. Does the trailor mode overide the torque bands electronically? All tests in lower gears in both vehicles produced sluggish trannies.

Cool! I'm happy to learn that if you select 2nd, that's what it starts out in. I'd have designed it that way myself. But, you're saying the GMC upshifts when it's in "trailer mode"? That's an interesting way to modify it too and it also makes sense. You'd want a 1-2 upshift when towing, I think.

About this sluggishness, I don't know. I wonder if the torque converter locks up quickly? It has to unlock to allow the vehicle to remain stationary with the engine running, but maybe once it's moving, it locks.

As another observation, I've never seen a lock indication when accelerating in drive with the OD on until I reach 4th gear, no matter how softly I try to accelerate or stabilize the speed early. And, we talked about this in another thread and I think it should lock in third if the OD is off and in 2nd if the transmission is set to run there and so on.

- Jack

Well I was hoping to hear from Bill on this one (I'm sure he is pretty busy) but there is a definate reduction in power. I monitored comm gear while taking off in 2nd gear, after a few seconds shifted to 3rd and it took off like a different truck. Didnt shift to 1st, nor did the tc ever lock. I wonder if it does it in 4WD?

We're back from Sedona. Here's what I learned:

If I start my truck moving with the shifter in 2nd gear, that's the gear it stays in - period! No 1st gear at all.

I observed my torque converter lock up in 2nd, 3rd and 4th gears, depending on the load and speed. Once in a while, it would shift from 3rd with the torque converter locked directly to 4th without unlocking the torque converter and that would feel "harsh". With the speed control on, coming down a hill, as long as the torque converter stayed locked, I could feel engine braking, but if I tapped the brake to disengage the cruise control, the torque converter would also unlock and the feel of engine braking would disappear.

The TC would lock in 4WD, which I used on a few "unmaintained" roads for improved traction and control. But, now I have a VERY dirty truck!

- Jack

Good info thanks Jack:thumbs up yellow:

That sedona red dirt/mud is alomost worse than beach sand isn't it.:gag::whistle:

For some reason, I've noticed that the truck will go into a reduced power mode in Manual 2nd Gear. I'm not sure what the purpose of this is other than to prevent burning up the clutches in the transmission by trying to start from a dead stop in 2nd gear. I've never really been concerned about it since this is not a normal driving situation for most folks.

By the way, you can manually recreate the symptoms. Put the truck in 2nd and take off from a stop. At about 30 MPH, matt the gas pedal and after a second or two shift from 2nd to Drive. You'll instantly feel a change in power output. Make sure you're not downshifting when you switch to Drive or it makes the whole test pointless. :whistle1:

The Sedona dirt is almost like red talcum powder! Super, super fine and all over everything. There was a very nice, steep, "sharp-rocked" road out of Sedona called Schnebly Hill Road that we drove up. Beautiful drive at about 5 -10 mph and a great test of tire durability. My understanding is that it was the original route in and out of Sedona. Doesn't look like much has been done to improve it since then.

Bill, I wonder if the reduced power in 2nd is just to minimize slippage on startup in snow or on ice? I do know though that it's a good gear to pull a trailer up a steep grade (7%+) in the mountains.

- Jack

Yes Bill, thats exactly what i'm talking about. Sometimes I drive in the mountains with some short but steep hills where I like to hold it in 2nd gear, but the power is just not there. I was wondering if it is an electronic thing that can be defeated with the programmer.

I'm still looking at that. We know where the throttle tables are but for some reason it doesn't seem to work on the 2nd Gear settings. :shrug: Fortunately, the Expy does the same thing and as soon as I have a little time I'll be fixing that. :2thumbs:

1st and 2nd gear positions cause the PCM to remap the throttle
essentially the throttle gets cut in 1/2 by placing the shift lever into 1st or 2nd. the throttle then is more "sensitive" and you have better control of the wheels.
this is achieved because you now have full pedal travel to control only 50% of your normal throttle...so you don't inadvertently spin the tires by giving it too much gas
it's a little known feature to help you control low speed situations. like boat ramps, towing heavy loads, 4x4 offroad

This is a response from Tylus on the FTE forum regarding the same issue, if it is the pcm remapping the throttle I would think it could be programmed to not do it. Or, perhaps there is a microswitch somewhere that can be bypassed. What do you think Bill?

That's exactly what it's doing and I do know where the map is. The problem is that when we change it to improve the range, it often (read that as nearly always) sets a Throttle Control DTC. That's what I'm trying to work around. :shrug:

Shouldn't this be "less sensitive"? (But I'm not trying to split hairs here, just trying to understand this). Effectively then, placing the shifter in 2nd (or even 1st) DOES make the truck less likely to spin tires on startup in a slippery situation.

But now, I've got another problem. From Tylus' explanation, it would seem that you are very limited in total power output if you have locked the transmission in 2nd. As I said in a previous post, that doesn't seem to be my experience, at least not when I'm towing my trailer up a 7% grade in the Colorado Rockies and passing every other RV and semi in sight (since I can maintain 65 mph and they can't). I lock it in 2nd to keep it from shifting back and forth between 2nd and 3rd in this situation which it will do on grades like this. This technique even seems to work on very "twisty" steep roads where the maximum speed is about 25 mph. I have no problem whatsoever getting everything moving from dead slow (around a severe switchback) while in 2nd gear. On shallower grades, of course, I can just lock the overdrive out to keep from cycling between 3rd and 4th.

I guess what I'm trying to ask in all this is: If my total throttle input is cut in half, where the heck am I getting all this power from? :shrug: Is it Bill's fabulous tune? :cheesy smile:

- Jack

I've thought about this some more, and maybe it works like this?

If we assume the change in Throttle Position (TP) vs Pedal Position (PP) is nearly 1:1 (linear) when the gearshift is in Drive, then possibly the change in TP vs PP is more parabolic with the shifter in 2nd or 1st? In other words, possibly TP reaches the same maximum point in the lower gears, but it does it more slowly at first?

Thinking about it, that's the way I would have designed the relationship, because there's no reason I can think of to limit the max TP.

(And I know the Drive TP vs PP doesn't have to be linear, I just used that as a base for comparison).

- Jack

Why mess with it? Someone along the lines must have thought it was important for something.

Good example Jack of mountainous driving.

Okay what if we get it changed and then one day we need it the way it was designed? Are we going to sit there and reprogram it while in potentially dangerous situation?

Just a thought

Lars

Thanks for looking into it Bill, let us know if you find anything out.

Jack... maybe the power is there in the upper rpm range allowing you to pull the hills, and the power reduction happens in the lower rpm range which is where you would be in a slippery condition. Just a thought. It seems as though Ford would have made this feature optional, (it's there if you need it).

From what I've seen, this phenomena only occurs at lower RPM ranges. Once you approach a certain RPM point, the map transitions to the standard throttle mapping. It just seems to make the throttle less aggressive to avoid losing control in slippery situations such as wet or icy roads.

This is one area I'm still trying to get figured out as far as when it transitions and just exactly how it fully functions. As Lars said, it's there for a reason. For some people it's an inconvenience and if they want it removed I'd like to be able to add it as an option.

Take care.

Orygun and Bill - I was trying to say what you just said in my post where I described the TP vs PP curve as parabolic. A slow rate of increase in TP at first, but climbing more rapidly at upper PP values until reaching the same (rates?) or TP values as happens in Drive.

And yes, this seems like a perfectly reasonable design strategy.

I probably should have tried to include a graph describing the effect, but I needed to do some work on the trees in our property.

- Jack

Now I am not trying to drag this out!

I agree with Bill if people want that option let them do it.

This just for curiousity: Does any one have a f150 stx with a mt and if so does it have a traction control button on the dash? I know most later model gm cars with mt have them and they act the same way once slippage is sensed. My parents windstar van has this button also and its an at.

I am just trying to show that in some other vehicles its just a button. It should make it easier to track down knowing that little piece of info.

From experiance in a 02 camaro mt the tc button did not help to win a race it made it feel like the f150's 1st and 2nd. Glad it wasn't for pinks.

Lars

On the 6.4L diesel, there is a switch to engage or disengage traction control if excess power causes traction loss. Many high performance vehicles such as Mustangs also have traction control, often with a switch to manually shut it off.

Jim,

In regards to the throttle control, as near as I can figure it isn't using a parabolic sort of curve... at least not as you described. It appears to be more that it transitions from the lower map to the normal map. I guess the effect would be the same, but it isn't handled in a single map.

Jim??? :confused: :giggle: :hehe:

Glad I'm not the only one that has momentary lapses!

A discontinuous curve makes perfect sense too. I was just trying to explain why I didn't seem to lose any high PP/PRM power.

- Jack

Had the chance to do a little wheelin the other day.... seems as though the infamous power reduction does not occur in 4LO. Hmmmm.

Well that one there might give Bill some more info on where the switch is in the program or module.

Good info.

Lars
:thumbs up yellow:

That is incorrect, I hate when people correct me but if in 2nd gear it will shift from 1st to 2nd and back down. In 1st it will not shift up to 2nd. :beers:

I guess my trans is messed up then. :shrug: If I place mine in 2nd it stays. No down shift no upshift.

It has been my experience that with most, not all, when you select 2nd with the shifter in an AT it stays in 2nd will not shift up or down. I have a 6.0 PSD with the 5 speed AT and when you select 2nd it will not leave 2nd, same is true when you select 3rd from a dead stop you start out in 3rd.

It has been my experience that with most trucks, not all, when you select 2nd with the shifter in an AT it stays in 2nd will not shift up or down. I have a 6.0 PSD with the 5 speed AT and when you select 2nd it will not leave 2nd, same is true when you select 3rd from a dead stop you start out in 3rd.

Sorry for the 2 posts... I am at work and the editing is not working and then I hit the browser back button... computer locked up... :cursin: I will try and the first one tonight when I get home and am on a decent computer:shrug:

That's the way it is on Fords. On GMs you'll often find that when you select 2 or 3, that's simply the highest gear you'll go. The vehicle will still start in 1st gear. Of course, this may be different on the very late model vehicles, but that's how I remember it.