Well, I can't speak for other tuning, but PPE's defuel is HORRIBLE with the bigger tunes (at least on my truck). After Mike's warning about tie-ups with big tunes and no defuel, I only ran w/o it on 90 and lower. My main concern is/was tie ups and MAJOR catastrophic damage. If/when Mike figures out how to prevent tie-ups altogether, I'd be very interested. I can handle replacing clutchpacks every year or two due to accellerated wear from non-defueled shifts. IMO, once the TCM learns, non-defueled shifts feel TONS better. I just want to avoid KA-BOOM! Anyway, I'm going to probably try to get the truck on a lift somewhere soon, get the trans out and get an autopsy done, then go from there. I probably won't run anything big once it's fixed until I get my engine work done (HOPEFULLY this summer, if this doesn't cost a fortune).
Allison 5sp: P0776 - Do I have big problems?
- Thread starter Cougar281
- Start date
if the truck is tunned properly , and you have a well learned tcm , and are not having low fuel pressures issues you would be suprized how fast and crisp the shifts will be with keeping the defuel in tact . if your shift are slow and drug out there is a reason and its not due to defuel . just my opinion .
GMC_2002_Dmax
The Still Master
I believe I mis-read your post Dave,
You are not running a TCM tune with the defuel request disabled are you ???
If you were not then I apologize for mis-reading the post.
Tony
You are not running a TCM tune with the defuel request disabled are you ???
If you were not then I apologize for mis-reading the post.
Tony
I have in the past, but at the time this happened, I was running with defuel. After Mike's warning about tie-ups with big tunes, I haven't run without defuel on anything over +90.
I have been having rail pressure issues (I have KD Twin lift pumps), so sounds like that may be part of the defuel issue. I was going to get into fixing that with a LBZ CP3 and WD regulator, but when I found the stuck glow plug and bad injector (in the same cylinder), I shifted my plan to converting the truck to LBZ engine, ECM/TCM (and all associated wiring, of course), then once I know it works with stock tuning and such, pull it and build it up, then go from there.
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Ok, trans is out (that was fun without a lift!) and apart. to my very untrained eye, none of the clutches look real bad, none where welded together. On a quick look, there was what appeared to be a burn spot or two in a place or two. The fluid was nasty compared to that dripping from the other Alli in my garage. The only "visible" issue to me was what I'm guessing are chatter marks on the C2 drum. I'll post pics of the clutches and C2 drum tomorrow. Anything else you'd like pics of Mike?
Is the P3 carrier supposed to come out with the extension housing? Any reason why I couldn't get the snap ring on the end out? one side of it would slide out, the other wouldn't budge.
I'm guessing that what happened is what I thought: the 3-4 blew through the clutches. It wouldn't surprise me if some of the frictions are thinner than the where new.
Is the P3 carrier supposed to come out with the extension housing? Any reason why I couldn't get the snap ring on the end out? one side of it would slide out, the other wouldn't budge.
I'm guessing that what happened is what I thought: the 3-4 blew through the clutches. It wouldn't surprise me if some of the frictions are thinner than the where new.
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Mike said that's normal. We don't like it, but normal. It's because of running big power, and having the thin steel always hitting the drum in the same place... Kinda like how the transfer case pump likes to rub through the housing.
Yeah, I'll try to do that tomorrow. I've also got to take apart the front pump assy. They're ok though, no hot spots or burn marks etc. Also, as noticed in a few of the pics, most notably #5 where the steel looks bronze near the inside, the fluid makes things look odd.
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Is that something new, I dont remember them being black. Im not disagreeing at all that the clutches are perfect judging by the steels there looks to be no problems at all, I just though they were orange??