Allison 5sp: How to make a high HP allison live???

Righteyeblind

Righteyeblind

Member
Aug 29, 2008
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Fairbanks, AK
So i'm fed up and racing season is over. I got in ZERO good passes this year and am going on my 6th time of pulling the trans. Other then sending my trans to Mike, which is not feasible from up here, what do I need to do to make my trans live? I had it on a real small tune ran 11.99@115 and then turned it up and adios C1 clutches.

I have replaced the whole drum, seals, pistons. C1's have fried twice, c-3's once, c-2's once, c2 hub/p2 planet once. Im am careful when I build my trans clearances all good. I have never had a problem until I put the horsepower to it now it won't live.

Whats done:
Alto C-5
GMAX C-4
Dual sided C-3 that Suncoast sent me because the GMAX ones didnt hold
alto c-2
16 SS C-1
Transgo/lockup valve with check ball removed and longer spring
ML pressure spring/Drilled seperator plate at pump
Cooler
1055

I am at a loss and would appreciate tips and advice.

Thank you
Reece
 
duratothemax

duratothemax

<--- slippery roads
Aug 28, 2006
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Reece have you tried a 6-speed front rotating assembly?

What pressure are you running? Have you checked it with a gauge to make absolutely sure you defeated lockup knock-down completely?

How many clutches in C2 and C3? I would switch to all alto's IMO. At extreme HP levels the GMAX clutches just dont hold up. (personal experience, seeing in real life, thats not hearsay or something I "just read")
 
Righteyeblind

Righteyeblind

Member
Aug 29, 2008
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Fairbanks, AK
Ben I havent check the pressure during lockup yet.
If my memory serves me correctly:
C2:7 frictions 8 steels I used 1 .086 steel in place of the .067 steel to bring clearences into spec.
C3:6 steels 5 frictions? this is what I think I forgot what George sent me but I think this is right. They are Dual sided frictions.
 
duratothemax

duratothemax

<--- slippery roads
Aug 28, 2006
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I would probably start by tracking down a 6-speed front rotating assembly. Thats the first thing that you should do IMO.

Or, even better, just buy a whole 6-speed core trans and put your 5-speed valve body in it. Remember you'll have to swap bellhousings through, due to the cooler-line-fittings difference in your 2002.
 
Righteyeblind

Righteyeblind

Member
Aug 29, 2008
712
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Tim my c1 clearance was at .100. As far as the c3 pack I talked to George and he knew what I'm up against so you might be right on the c3 amount of frictions.
I will look into getting a 6 speed drum. I had no idea they were that much stronger.
 
Burn Down

Burn Down

Hotrodder
Sep 14, 2008
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Boise Idaho
Righteyeblind said:
Tim my c1 clearance was at .100. As far as the c3 pack I talked to George and he knew what I'm up against so you might be right on the c3 amount of frictions.
I will look into getting a 6 speed drum. I had no idea they were that much stronger.
Click to expand...

Time to call the russian... :D
 
duratothemax

duratothemax

<--- slippery roads
Aug 28, 2006
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well its not really that they are "stronger" per se.

They just apply C2's much more cleanly, evenly, etc. Balance piston is eliminated. Reduces risk of tie up on the 3-4 in high HP applications...
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
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Chesterfield, Mass.
Righteyeblind said:
Tim my c1 clearance was at .100. As far as the c3 pack I talked to George and he knew what I'm up against so you might be right on the c3 amount of frictions.
I will look into getting a 6 speed drum. I had no idea they were that much stronger.
Click to expand...

In my opinion, that's why your c1 are frying. Set them looser. More volume of fluid behind that apply piston, the stronger it is
 
duratothemax

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
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Wyoming
juddski88 said:
More volume of fluid behind that apply piston, the stronger it is
Click to expand...

fluids are incompressible, and you arent changing the size of the piston........

Its not like the mainline pressure is being increased/decreased based on how much fluid goes into the piston when it applies, so how does "more volume" of fluid make it "stronger"? :confused:
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
4,655
120
63
Chesterfield, Mass.
call me crazy Ben, but isn't fluid dynamic? properties change between hot and cold conditions. there is a fill and exhaust, the exhaust is not "closed off" per se. with more volume there is more fluid starting behind the c1 apply plate when fluid starts to leak out. I know you run your c1 clearance the same as me bud, not sure why you wanted to disagree? I run .115"-.125"
 
IOWA LLY

IOWA LLY

Yes, its really me
Feb 23, 2007
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When did C1's let loose? Spool-up, launch, or down the track a ways on a shift?

You really need to monitor mainline pressure so you can see whats really going on.
 
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