6 speed input drum

mike diesel

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Sep 6, 2012
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Curious where a guy finds a 6 speed input drum assembly at?..

Figured if I'm pulling my trans to refresh it, I would want to swap in a 6 speed input drum assembly in place of the 5 speed drum assembly. Also, what is the going rate on a 6 speed input drum assembly?
 

greendury

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Jan 28, 2011
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You would be able to get one at any Allison distributer dealer. I can look at work Monday to see what list price is for one.
 

mike diesel

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Sep 6, 2012
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You would be able to get one at any Allison distributer dealer. I can look at work Monday to see what list price is for one.

That would be good thanks. If you or anyone else has a part number that would be good to. I'vegot an allison dealer just down the street but unless you have a specific part number to give them, it's a circus show watching them try to find what you need.
 

dmax02

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May 30, 2009
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Don't get it from transmission parts technology still trying to get my refund for the wrong parts they sent me! Ended up calling Transtar they got me one for around $200 :thumb:
 

Mike L.

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If you do not mind, could you explain the improvement this makes on a 5 speed?

The 6 speed C2/C1 pistons offer larger apply area ( pressure X area = force ). Plus the 5 speed C1/C2 pistons do not hit the direct center of the clutches on apply, so you loose almost 50% of holding power. Thicker apply plates have more or less solved that problem.
 

Slowmax

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Aug 3, 2013
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The 6 speed C2/C1 pistons offer larger apply area ( pressure X area = force ). Plus the 5 speed C1/C2 pistons do not hit the direct center of the clutches on apply, so you loose almost 50% of holding power. Thicker apply plates have more or less solved that problem.
Thank you very much for the knowledge it is greatly appreciated.
 

mike diesel

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Sep 6, 2012
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So since I doubt I will be able to find an entire 6 speed c1/c2 input drum assembly unit ready to drop into a 5 speed minus the "go fast" upgrades, does anyone have part numbers (or the rest of the parts) I will need to make a bare 6 speed drum ready to use?

I've never seen a 6 speed drum and internals so right now I'm not entirely sure what one looks like compared to the 5 speed drum and internals.
 

Mike L.

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I'm not all that enthused with the idea of using a 6 speed rotating assembly. They will twist the spline on the C2 hub and planet. Properly set up 5 speed rotating assembly will not.
 

mike diesel

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Sep 6, 2012
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I'm not all that enthused with the idea of using a 6 speed rotating assembly. They will twist the spline on the C2 hub and planet. Properly set up 5 speed rotating assembly will not.

That was actually my next question.. I was going to ask if I should even worry about spending time and money gathering parts for the 6 speed drum when I already have something to work with. I guess that answers my question:D
 

Evan@InglewoodTrans

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Aug 5, 2010
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That was actually my next question.. I was going to ask if I should even worry about spending time and money gathering parts for the 6 speed drum when I already have something to work with. I guess that answers my question:D

If it isn't set up right you will have the same problem as 6 speed drum for sure. The last time I tore down a fairly high horse power 5 speed with a 6 speed drum we had zero issues with tie ups. The first time around we had issues with the same drum and twisting splines. When the Trans came to me to be built the first time it had a properly set up 5 speed drum and the p2 was twisted as was the sleeved hub so I've seen it go both ways. No tuning changes were made between builds.
 

mike diesel

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Sep 6, 2012
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The main reason I wanted to switch to the 6 speed drum was because I thought I saw the 6 speed drum doesn't use the balance piston like the 5 speed drum does, no balance piston results in much less chance of tieing up the 3-4 shift. Which i already know my c2 clutches aren't ideal (8 red eagle clutches) as apposed to 7 clutches in a much better laid out trans "kit". So I figured between a 6 speed drum and a properly spec'd set of c2 clutches, I would have slim to no chance of tie ups.

But if a properly set up 5 speed drum is acceptable then I will stick with what I have and refresh the trans with better parts this time around. I'm sure my c2's and c3's have seen better days. Stock tcm tuning has hopefully kept my c2 hub and planet splines in good shape.
 

Mike L.

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The main reason I wanted to switch to the 6 speed drum was because I thought I saw the 6 speed drum doesn't use the balance piston like the 5 speed drum does, no balance piston results in much less chance of tieing up the 3-4 shift. Which i already know my c2 clutches aren't ideal (8 red eagle clutches) as apposed to 7 clutches in a much better laid out trans "kit". So I figured between a 6 speed drum and a properly spec'd set of c2 clutches, I would have slim to no chance of tie ups.

But if a properly set up 5 speed drum is acceptable then I will stick with what I have and refresh the trans with better parts this time around. I'm sure my c2's and c3's have seen better days. Stock tcm tuning has hopefully kept my c2 hub and planet splines in good shape.

8 clutches in C2 has not helped your tie up.
Remember that the Transgo shift kit was designed for a stock trans. The bottom C2 piston holes that you restrict with the cup plugs eliminates what the balance piston does. So in theory; you have gone from about 11" of apply area to about 19". so to speak. Doing this caused a violent 3/4 shift. hence the stronger return springs supplied for the C2 piston to tame the shift down and stop the big tie up that was caused by this mod. Now we add 8 Alto Red Eagle clutches which are far more aggressive than the 6 Borg Warner clutches and all bets are off. You now have the worlds biggest tie up.
Anytime you feel a hard shift in a Allison trans; the rear wheels locked up for a split second. Not good.
What a lot of tuners don't realize when they play with TCM tuning and think they cleaned up the shift and made it feel more like a turbo 400; they screwed it up. It is a proven fact that you will go faster with defuel than messing with it and locking the rear wheels up with your so called tuning.
The Allison needs to go into neutral for a millisecond to make a clean hand off to the oncoming clutch. I've seen a Allison engineer play with the TCM adjusting the ramp rate on the trim solenoids and clean up the shift very nicely. We can not do that.
 

mike diesel

I'm alright.
Sep 6, 2012
4,005
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36
SLC, Utah
8 clutches in C2 has not helped your tie up.
Remember that the Transgo shift kit was designed for a stock trans. The bottom C2 piston holes that you restrict with the cup plugs eliminates what the balance piston does. So in theory; you have gone from about 11" of apply area to about 19". so to speak. Doing this caused a violent 3/4 shift. hence the stronger return springs supplied for the C2 piston to tame the shift down and stop the big tie up that was caused by this mod. Now we add 8 Alto Red Eagle clutches which are far more aggressive than the 6 Borg Warner clutches and all bets are off. You now have the worlds biggest tie up.
Anytime you feel a hard shift in a Allison trans; the rear wheels locked up for a split second. Not good.
What a lot of tuners don't realize when they play with TCM tuning and think they cleaned up the shift and made it feel more like a turbo 400; they screwed it up. It is a proven fact that you will go faster with defuel than messing with it and locking the rear wheels up with your so called tuning.
The Allison needs to go into neutral for a millisecond to make a clean hand off to the oncoming clutch. I've seen a Allison engineer play with the TCM adjusting the ramp rate on the trim solenoids and clean up the shift very nicely. We can not do that.

Oh yes i remember those plugs in the c2 piston. What can I do to eliminate the tie up other than getting rid of the 8 clutches in the c2? Or will that alone keep things happy?
 

mike diesel

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Sep 6, 2012
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SLC, Utah
I understand some of this info you learned the hard way and probably don't want to give it out which is perfectly fine and I understand fully. I figured there is no harm in asking and worst you will do is tell me to take a hike:hug:
 

trailler2004

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Jan 14, 2013
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thanks for sharing knowledge mike l
ive also contemplated on trying a 6 speed drum but maybe keep doin the 5 speeds the same lol