2006 Chevy 3500 Duramax-Cummins Swap - The continuing saga

deerefanatic

Always learnin...
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Aug 27, 2011
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So, many of you probably thought I dropped off the face of the planet.. Well, life got crazy and the project stalled out.. For those not in the know, the original thread (which is closed) is here: 2006 Chevy 3500 Duramax-Cummins Swap - Competition Diesel.Com - Bringing The BEST Together

I had the truck to the point where I needed to purchase the trans controller from Jason at transmission tuner.com, and then get driveshafts redone... And odds and ends like radiator hoses, fan belt, ac hoses, etc... Then I lost my day job and money dried up.. Got a new job at a heavy equipment shop, but wasn't making the kind of money I used to.. Throw in marriage and a kid on the way and the project stalled out. then I had some jacka$$ co-worker at work that just HAD to have the truck, and wanted to leave it a Duramax.. So I bust tail to pull the cummins and related stuff out, send the torque converter to be restalled, and then he totally flakes on me.

So I'm pretty much set on moving forward with this. I thought briefly on building a good LBZ, but when I found that just the parts bill to rebuild it to be a reliable 1200 ft-lb tow rig is over $3600 (and that's wholesale price, not retail) I said screw that noise.

1st question: Who has had a 1000-1200 ft-lb mechanical cummins in front of an Allison 1000 and had it hold together? That's what is scaring me. The trans has been gone through completely by my buddy Stan (he's a long time member here.. He was one of the first guys to put a VGT holset on a 12v back in the late 2000's). It's got Alto G3 clutches throughout, increased line pressure, some pump mods, Transgo Jr. No billet. Stan says he'd consider the trans good for a 900hp duramax, minus the billet parts. Being my truck will never see a track, I didn't feel Id need them.
 
Pm T-man on here. He has a 2nd gen with an Allison that is dialed in. Truck runs low 11's.
He's a helpful guy, wouldn't mind.
 
Your trans guy is lying to you about that 900hp capable build. You could get buy at 600hp for a while. Just don't try using 600hp alot while towing and expect that trans to live.

Sent from my SM-J260A using Tapatalk
 
Your trans guy is lying to you about that 900hp capable build. You could get buy at 600hp for a while. Just don't try using 600hp alot while towing and expect that trans to live.

Sent from my SM-J260A using Tapatalk

How so? The shafts or the clutches? My understanding is the G3's are one of the better clutch choices out there. He also said that line pressure is up about 30 psi at peak, and the cutback valve only will drop about 5 or 10 psi. T-Man and I talked at length today and he seems to think I'll see hard part problems before clutch issues.
 
I've had the same mods doing the same thing your wanting to do. I'm just stating my experience. Clutches went first time. Clutches went the second time. Hard parts third time. Everything back to stock for the fourth one. Been fine ever since.

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Tell me more... Who's trans controller setup? Allison Medium Duty or an 8.1 style controller? What kind of weight were you towing? Rear end gears?
 
First one was a stock rebuild, transgo jr. Second was alto's ,full trans go, third was a (stage 4) blah blah from ats, 5 star, copilot, total waste of money. Never broke a shaft, but I've cracked drums, and chipped/grinded gears from harsh tie-ups. I put an average of 60-70k miles on all of those, except the ats. It only made it 40k. I tow a 8k lb trailer almost every day, and mix in 13-15k at least 4 times a week. With the occasional 20-22k a couple time a month. plowed snow while towing 2 skid steers on my goose neck to open up sites quick. Usually average 50-60k miles a year. Truck has 400k and it's not my daily anymore. It's currently waiting for a injector to be replaced. Dam lb7's..... but I just can't bring myself to sell the dam thing...

Sent from my SM-J260A using Tapatalk
 
I've had the same mods doing the same thing your wanting to do. I'm just stating my experience. Clutches went first time. Clutches went the second time. Hard parts third time. Everything back to stock for the fourth one. Been fine ever since.

Sent from my SM-J260A using Tapatalk

This is what I actually said, basic kit and mods ….. clutches were burnt. built a better mouse trap and raised line pressure and burnt clutches, third time I made my own setup with the clutches and steels available on the market, put the line pressure north of 300 and started having issues with the p2 hub.. 3 of them actually. after that it was billet p2 and c2 hub and I haven't looked back after 70+ passes and about 750 hp. Tuning is 100% key to these things living after you get clutches setup right. A tie up is hell on the hard parts. I will say each time i broke a hub the clutches still looked perfect after I got them straightened out. If the trans was set up correctly and Jason tunes it towing with 600 wont be an issue. The c3 clutch is the troublemaker. And I agree 900 hp while towing wont fly for very long
 
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