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2015 Lml transmission ? (Greg?)

gonefishin

gonefishin

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so I have a couple questions. My truck has ppei tunes and trans tuning. I keep it on the max effort tune. Supposed to be 600hp 11** Tq. I tuned at 25k miles. Now have 35 k.

They said with the trans tuning the stock trans can handle 650hp. I think I feel my converter or something slipping when I'm really getting on it. I'm not easy on my truck by any means. It's on the floor a lot.

1. should I be running in tow haul mode when I'm ripping on it? What does the tow haul mode do for the trans?

2. When I shift manually with the buttons it seems to shift faster and harder. What extra is going on in the trans when I shift manually? Is there any way to make it shift like that all the time?
 
Are those specs flywheel or rear wheel? Are they PPEI canned tunes or efi live tunes. I believe that they have different tunes for stock trans and built trans. 600hp/1100tq at the flywheel is up there on a stock trans.

Look on duramax forums dot com. They have a section called "Mike L's trans talk" Mike owns Inglewood Transmissions and is the Allison guru.
 
It's his efi live tunes. I think flywheel hp. I also have full deletes, 4 inch exhaust, lift pump, and k&n filter.
 
Normally, if the trans even starts to slip, the lml's will defuel to save the trans. Allisons will kick a check engine light if they slip. Converter slip feels like a chatter more than a slip.

Are you sure it isn't just spinning the tires? My lb7 tuned around 600 at the motor will spin 35" tires into 3rd or 4th when provoked. I usually keep it in the 525 tune for better drivability, and for the sake of the poor tires.
 
I agree it has no issue spinning the tires. I'm well into my second set already at 35000 miles.

It feels like The converter is loose. It will flash to 3000 rpm very easy and then starts grabbing kinda. It's like the converter isn't locked good.

And i do have it tuned for stock trans. I feel it defuel on shifts. And occasionally it feels like it defuels extra and totally falls on its face after a shift.

Also trans seems to hunt for gears while downshifting sometimes.
 
The falling on its face after the shift, is the defuel to save the trans.
Change the spin on filter. Cut the old one open and see how much crap is in it. It's always amaizing to see how much better an Allison behaves with a new filter.
 
ChrisPerry said:
The falling on its face after the shift, is the defuel to save the trans.
Change the spin on filter. Cut the old one open and see how much crap is in it. It's always amaizing to see how much better an Allison behaves with a new filter.
Click to expand...
and for Allison spin on filter changes if its your first time check for the magnet .

remove it from the old filter / clean it / stick it back up on the spin on thread post and install new filter .

I have seen lots of them were someone did a filter change and didn't save/reuse the magnet as it sticks to the filter more than the center post .
 
My uncle had his ally built by MIke L he is he shiznit on ally transmissions.. that's money well spent.
 
Running in tow haul and manually shifting does change the pressures in the trans so you are probably feeling that difference. As others have mentioned if this trans slips the computer catches it right away and will store codes relating to the slipping component circuit. If you drive hard, frequent services will be a good idea.
 
Thanks everyone for the replies. I feel a little better knowing that the computer catches it so quick. I think I might be right on the edge of what the converter can hold. Or the converter is just a little looser than I expected.
 
Fuel filter also plays a very big role in the defuelling/shifting. My Dmax is long gone now but whenever the shifting started to act up the fuel filter was the first thing I would change and then the spin on trans filter. Sounds like yours needs to be changed anyways. Be sure to use a genuine Allison filter and they are WAY cheaper at an Allison dealer vs the GM dealer

Also like said before the computer instantly catches any slippage in the driveline and will jump in to limp mode. If it happens you'll know it.
 
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