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I have a buddy with an LLY that is having issues. He has a PPE stage 5 with an ML converter. He has broken his flexplate and flywheel it is shifting so hard around 54 mph, it barks the tires when it does it, or drags them not sure which. I had Rob build a custom tranny tune to lessen the torque converter lock and smooth out the shifts as much as possible and it is still shifting VERY HARD, only at this one shift. The truck does have a 6" lift with 35's on 20's and is running tunes built by Rob. I am trying to figure out if his low fuel pressure could cause it to shift this hard or if we need to have my builder pull it and check the tolerances in the C2 and C3 clutch packs. it does the hard shift no matter if it is in t/h or not so I don't think it's the converter. Anybody else have an issue like this before they resolved?
 

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whooooooooaaaaaa, that's a hard shift. Even without a lift pump and having low rail pressure on a high tune I don't think it would back down that hard out of a gear. I really think it would something with the trans, I'd get with the builder.
 

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Something is not right -- you should not have that hard shift. The problem is not the tune or the converter-- you have a big problem with the trans. It is not the PPE kit causing the problem. It is how it was put together.

Who did the rebuild-?
Does it shift OK at lower speeds?
Do you have any codes-?
 

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Discussion Starter #4
Something is not right -- you should not have that hard shift. The problem is not the tune or the converter-- you have a big problem with the trans. It is not the PPE kit causing the problem. It is how it was put together.

Who did the rebuild-?
Does it shift OK at lower speeds?
Do you have any codes-?
The same builder who has built all of mine, the others shift great.

It shifts perfectly through the rest of the gears, even the one that shifts hard under WOT?

No codes except for ABS codes?
 

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The same builder who has built all of mine, the others shift great.

It shifts perfectly through the rest of the gears, even the one that shifts hard under WOT?

No codes except for ABS codes?
mine sort of does the same thing. under WOT or light throttle it shifts great but mid-3/4 throttle it will bang into gear right about 55. kind of a trans confusion all most. I am wondering if maybe the stock gearing and 35" tires are putting a load on the trans and making it shift harder under mid throttle? mines not barking the tires but it does kind of surprise you. It gets really bad if your WOT and then let off right before the hard shift spot
 

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mine does the same thing . shifts really hard from for to fifth and on TC lock up in fifth gear. only happens from 3/4 throttle and up.
 

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I have a friend that has this same problem...not as bad but we attributed it to his torque converter he runs a ATS five star. but after hearing this it must be somthing internal.
 

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Might be a good question for Mike L. He is considered by most as the allison guru. I'd give him a shout.

jm .02 cents
 

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When i first had mine done it would rattle your teeth it would shift so hard going into 5th....4-5K miles later its as smooth as glass....guess it takes a 1058 a little while to wear in!:eek:
 

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My dmax-4 kit with a Precision converter has been smooth and solid from day one..... Have any of yall tried resetting TAPS with a Tech-2?
 

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Discussion Starter #11
My dmax-4 kit with a Precision converter has been smooth and solid from day one..... Have any of yall tried resetting TAPS with a Tech-2?
I always reset with a tech 2, nothing else makes them act so funky after.:cool:

Every other trans that this guy built shifted SMOOTH from the dig, hell I had mine at the track running the 1/4 four days after the build with 400 miles on it!

I talked to the guys at Trans Go, they said to remove the filter magnet, it restricts flow and reset the taps and cells, then give it 400 miles to relearn.
If that dosen't work the valve body is comung out for a cleaning and inspection and most likely the springs in the jr part of the kit will be replaced. I will keep yall posted on the progress, I too am curious if the 35's are the culprit.
 

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I always reset with a tech 2, nothing else makes them act so funky after.:cool:

Every other trans that this guy built shifted SMOOTH from the dig, hell I had mine at the track running the 1/4 four days after the build with 400 miles on it!

I talked to the guys at Trans Go, they said to remove the filter magnet, it restricts flow and reset the taps and cells, then give it 400 miles to relearn.
If that dosen't work the valve body is comung out for a cleaning and inspection and most likely the springs in the jr part of the kit will be replaced. I will keep yall posted on the progress, I too am curious if the 35's are the culprit.
Pulling the magnet out is just plain insane. Spin on filter works off of much lower pressure. ( 125psi in and out ) There is no restriction there. I am suprised Transgo would say this. They know better.
 

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Discussion Starter #13
Pulling the magnet out is just plain insane. Spin on filter works off of much lower pressure. ( 125psi in and out ) There is no restriction there. I am suprised Transgo would say this. They know better.
I thought that was a little off myself. What do you think the issue might be Mike?
 

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Clutch clearance cannot cause a hard shift. Problems with the trim valves and balls can. Misplaced balls for the trim valves will cause all kinds of nasty problems.
 

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Discussion Starter #15
Clutch clearance cannot cause a hard shift. Problems with the trim valves and balls can. Misplaced balls for the trim valves will cause all kinds of nasty problems.
Is it best to just install a new jr kit to try and correct it, or do you have another method? Thanks Mike.
 

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Discussion Starter #16
Replaced the A and B trim solenoids and the truck shifts great now, no banging.

Only problem is that the owner had GM reflash the tcm and now it won't let me load his trans tune from Rob. Anybody else ever expirence this?
 

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oldschool
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Replaced the A and B trim solenoids and the truck shifts great now, no banging.

Only problem is that the owner had GM reflash the tcm and now it won't let me load his trans tune from Rob. Anybody else ever expirence this?
maybe running a different OS, it happened to me

so is that shift just as smooth as the rest now? seems mine might be the TC lockup. 5th has a hard shift when I'm driving the truck hard, if I keep it in 4th it will start shifting hard in that gear also
 

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I have pretty much the same issue. Violent shifts from 3-4 in a fairly fresh rebuilt transmission by a person that has done many trans and came highly recommended by many. Experimented last weekend and it seems to shift great when coolant temp is under about 160-170 degrees. I am unsure on these but in a gasser I don't believe that the torque converter can lock up until about that temp. Is that the case on these transmissions as well? Does this make any sense? I considered getting a separate temp sensor and hanging off outside of the coolant to further verify this.
 

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Discussion Starter #19
maybe running a different OS, it happened to me

so is that shift just as smooth as the rest now? seems mine might be the TC lockup. 5th has a hard shift when I'm driving the truck hard, if I keep it in 4th it will start shifting hard in that gear also
As far as I know his is fixed..........................
 

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Discussion Starter #20
I have pretty much the same issue. Violent shifts from 3-4 in a fairly fresh rebuilt transmission by a person that has done many trans and came highly recommended by many. Experimented last weekend and it seems to shift great when coolant temp is under about 160-170 degrees. I am unsure on these but in a gasser I don't believe that the torque converter can lock up until about that temp. Is that the case on these transmissions as well? Does this make any sense? I considered getting a separate temp sensor and hanging off outside of the coolant to further verify this.
Get someone with a V2 or a Tech2 to look at the trans, you might be having pressure flairs that are causing the hard shifts. That is what this trans was doing, we replaced the A&B trim solenoids and the pressure are normal now and the truck shifts great.
 
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