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Discussion Starter #1 (Edited)
Hesitation when accelerating

It has the basic power mods (injectors, edge, exhaust, intake) and a built transmission with 300M and billet internals + a DTS converter.

The truck pulls great with one exception........

When asking it to do more than standard crusing on the highway (example = accelerating up a long hill) is gets a miss.

It seems to hook up great off the line and runs fine while getting up to speed but it is the 55+ area where it acts up.

The RPMs hold solid and the torque converter stays 100% locked.

Any advice is really appreciated!!
 

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see if you can pull some codes and dose the truck have a trans temp gauge on it
 

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I noticed this after installing my quadzilla adrenaline when I cruise along at a higher power settting. Only around 50mph, in 4th gear with light throttle. Maybe around ~1500 rpm. To me it feels like the motors lugging and you can feel each cylinder fire. Best way I can describe it. I figured the things just getting a lot of fuel but the motor can't spin faster as it wants to due to the big load and lower RPM. As long as I don't have the programmer turned up while trying to lightly accelerate just after dropping into OD with the converrter locked I'm fine. If I turn the quadzilla down the problem goes away.
 

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Discussion Starter #4 (Edited)
see if you can pull some codes and dose the truck have a trans temp gauge on it
It has a gauge and the temps stayed very low (less than 125 degrees the entire time)
 

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Discussion Starter #5
I noticed this after installing my quadzilla adrenaline when I cruise along at a higher power settting. Only around 50mph, in 4th gear with light throttle. Maybe around ~1500 rpm. To me it feels like the motors lugging and you can feel each cylinder fire. Best way I can describe it. I figured the things just getting a lot of fuel but the motor can't spin faster as it wants to due to the big load and lower RPM. As long as I don't have the programmer turned up while trying to lightly accelerate just after dropping into OD with the converrter locked I'm fine. If I turn the quadzilla down the problem goes away.
This is interesting, I unhooked my EDGE box last night and it seemed to help the issue. There was noticeably less power but MUCH less of a shutter/hesitation problem.

I figured if it was a torque converter issue that it was helped by having less power but maybe it is fuel/engine related???
 

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shudder

I'm haveing same prob.I have run without adren.Is better but still does it.Also mine is worse with trany ats commander locked up.
 

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Im having the same problem with Quad in settings above 2, the power settings. It shutters or stumbles under a medium pedal. I just posted a simular thread hope we'll get a fix. Im thinking redownload program to see what that does, until someone has a better answer.
 

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shudder

Mine does it with quad on or off the truck(is def worst with it turned up past o)but mine will do it with box off the truck completely.
 

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Discussion Starter #9 (Edited)
I did a little more testing today - this time with no trailer.

The truck still had the issue. These are my observations:

- Grips very hard and shifts fine in first and second gears
- 99% of the problem is when it hits overdrive and I stay at medium + throttle
 

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Well, I'm not much of an expert on the 48RE trans (which is what I presume you have), but shudder at medium-to-heavy throttle in OD sounds like torque converter clutch (TCC) shudder to me. Does the shudder go away as the engine speed increases?

The engine torsional vibrations increase as engine speed drops. Your crankshaft torque is not constant, but rather fluctuates as the individual cylinders fire. Let's say, for example (to pull numbers out of the air) you are at 400 ft-lbs nominal engine torque. At 2000 RPM, the actual torque may be 400±10 ft-lbs (10 ft-lbs being the torsional fluctuations). Let's say further that your TCC can hold 435 ft-lbs. So you are OK at 2000 RPM. But as your engine speed drops, the torsionals go up. So let's say at 1600 RPM you are making 400±30 ft-lbs, and at 1500 RPM you're making 400±40 ft-lbs. When you get down to that speed range, each time the torque peaks (at 440 ft-lbs) it breaks the TCC loose. Then when it drops back down, the TCC grabs again. The TCC breaking loose is what gives you the shudder. Note that I have no idea what the actual numbers are; these figures are just for an example and may bear little resemblance to reality. But I suspect, if the shudder goes away above a certain engine speed, that you are likely breaking the TCC loose due to the torsional vibrations.
 

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If this is the case is it just a new torque converter that is needed or total rebuild w/torque. Also what type in torque can the input shaft handle vs billet?
 

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If this is the case is it just a new torque converter that is needed or total rebuild w/torque. Also what type in torque can the input shaft handle vs billet?
I don't have any specs on input shaft torque limits, and in any event, life is inversely related to torque, so the real question is not "what is the limit?" but rather "how long can i run at XXX torque level?" Higher torque will give shorter life, but really the "limit" would be the level that snaps the shaft in half the first time you nail it. But you probably don't want to be anywhere near that "limit." You want something that will last for thousands of miles (at least) I would think. So I can't give you any numbers, unfortunately. The weak point is typically the cross holes, so the most critical thing for shaft life is not necessarily whether the shaft is made from a billet, but how smooth the edges of the holes are, how well they are shot peened and heat treated, etc.

As to the TCC slippage, hard to say since it could also be one of the clutches inside the trans that's slipping. Best solution is either back off the torque level, or shift to 3rd gear to raise the engine speed and avoid the shudder.
 

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shudder

But why would it be worse with the tc locked with (comander in my case)then in reg mode???and thanks for your input
 

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But why would it be worse with the tc locked with (comander in my case)then in reg mode???and thanks for your input
The converter is a fluid coupling, so torque is normally transmitted via fluid (oil) that circulates between the impeller and turbine. When the TCC is unlocked, this fluid coupling dampens out the torque fluctuations from the engine. But the TCC is a direct mechanical link, so the torque fluctuations are passed through, rather than dampened out.

The impeller and turbine speeds normally vary from each other (and this doesn't cause any vibration or shudder). You only feel shudder when the TCC slips and grabs.
 

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Why is it so difficult to understand TC Shudder as converter clutch slippage/attempting relocking. The modded diesel makes tremendous torque at light throttle and low RPM. Even a manual clutch is more likely to slip at similiar low rpm high power levels. If you increase power, you must also increase capacity of other components. sometimes the fixes by aftermarket with limited test capability are not adequate...
 

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Discussion Starter #16 (Edited)
Are there any other common causes of shudder in our trucks that I should be looking at?

I have read some Ford forums where they struggle with injectors and fuel delivery creating very similar symptoms.
 

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I have a DTT triple disc converter and I don't think an adrenaline on a low setting could makeit slip as described in this thread. I still think its that its locked up so tight, and at lower RPM each combustion event is more pronounced and separated and that's what we're feeling.

If your worried about your Trans maybe a check of the band adjustments may give a lil piece of mind or help in some way?
 

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Quote: The frustrating part about all of this is that the truck has not been changed in 5+ years.

Same power mods, same ATS converter and built trans.

Truck was running fine when I pulled it into the shop. Dropped the pan and changed the tranny filter...............now I have the shudder (end quote]

What type of fluid was in tranny before and what did you put back in? Brand and type??
 

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Discussion Starter #20
Quote: The frustrating part about all of this is that the truck has not been changed in 5+ years.

Same power mods, same ATS converter and built trans.

Truck was running fine when I pulled it into the shop. Dropped the pan and changed the tranny filter...............now I have the shudder (end quote]

What type of fluid was in tranny before and what did you put back in? Brand and type??
Had AMSOIL ATF in it before, filled it back up with the same.
 
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