I have a 2004 ext cab 4x4 duramax with the lly engine. I have 4inch straight pipe and intake and 33s and 20s. I just purchased a diablo predator.. If I were to make one good 1/4 pass with it all the way up what kind of 1/4 time would be expected? Also will I be ok running it easy on the 85hp tune?

You have to drive it a while before it will learn to shift with the extra power............so your 1/4 mile would probably be off if you just threw it in for one run!!

I imagine my truck would run 14.20's or something ......but I have not ran it yet !!

I limped my trans. the first time I ever got on it hard in 5th gear on the 85 tune !! Some guys run them for a while with no problems !! Your problems will really come in at the 4-5 shift or 5-4 shift...........or like me and all limps will come rolling into it in 5th gear when it doesn't downshift !!

If you do not wan to flirt with tranny problems ..........I'd just run the 40 tune. Even though it's unlikely .......there are guys on here that have limped with just the 65 tune !! Personally I would not run over the 65 on a stock tranny..........it's still a 14.80 or so tune and is much safer on your tranny and your FPRV !!

Same here, i limped my truck with the 85 tune. Plus you put a little more strain on it to with larger tires too.

What makes the transmission go into limp mode and how do you make it to where it won't do that anymore?

The trans. senses some slip and puts the truck into limp mode to protect it. It will drop into 3rd gear an you lose power but you can pull over and give it a minute and it will fire up and be fine(with just a CEL on for many key cycles). But once you limp it.......it's easier and easier to limp. I dropped mine from the 85 tune to the 65 tune and ran it for about 6months before it started limping on the 65 tune..........but by then.......when it started limping it limped easy in 5th gear .

The only alternative at that point is to get a rebuild.........and you might as well get a full blown deal at the point because it cost nearly as much to get it rebuilt back stock !! I opted for a SC3 kit which cost about 4k intalled with fluids, labor, transfer case brace, and all !!

Does the predator defuel on shifts? My girlfriends dad has ppe xcelerator on his 06 and he doesn't have any kind of limp mode.. Is it because it defuels the shifts and isn't such a shock on the trans when downshifting and upshifting?

85 tune makes good power. It is a crap shoot as to your tranny holding it or not. Mine held if for a long time, never limped it and I drove it hard. I drove 10-12 K on 65 tune before moving up, made the move to 85 because I had tranny thoughts.

Might help us if you fill out your sig, so we know you specifics.

Well I g uess Ill just have to load it up and see what happens.. Would the transgo jr kit help any with limp mode?

Well I g uess Ill just have to load it up and see what happens.. Would the transgo jr kit help any with limp mode?

transgo would help, but not solve the problem. The converter needs replaced, and if you are going to do that, might as well just do a SC III.

Predator defuels on shifts but that doesn't help in 5th. Predator's put down more power than they are rated and they are rated at rwhp............PPE rate's hp at the crank. So you have to watch how much torque your actually throwing at the tranny.

Trans-go Jr are good for 6 speed Alli's because they already have some mod's that the 5 speeds do not. But the Jr. is not much benefit to the 5 speeds. Really you need a full trans-go kit and a good convertor........and like Stove said.......by that point you might as well get a SC3 kit !

No free lunch with these things !! If you get lucky.........you may run the 85 with no problem.........but "if" you don't get lucky..........??????

gotcha.. What do yall guys do about valve bodies?

I ran a 14.9 in 2wd with the 65hp predator tune.

My truck limped also on the 85 hp setting. The truck was empty and I was getting on the freeway. I cant believe the trans would sence a slip condition empty. I can have the truck loaded with my camper and boat pull hills in 5th gear with no codes w/o the programer installed. I would think that would have more strain on the trans than rolling onto the freeway:cool:

My truck limped also on the 85 hp setting. The truck was empty and I was getting on the freeway. I cant believe the trans would sence a slip condition empty. I can have the truck loaded with my camper and boat pull hills in 5th gear with no codes w/o the programer installed. I would think that would have more strain on the trans than rolling onto the freeway:cool:


Did it trip the engine light? Did the tranny stay in second? 1093 is often mistaken for a tranny limp, but it is low rail pressure. I never 1093'ed with my predator, with a clean filter. A dirty filter will cause low rail pressure. With my kill tune I could 1093 a will, until the fprv was replaced with a race valve.

I slipped with the 85 hp, had it in only for about 2 weeks, but had 65 hp in for 2 years. Passing a semi and the 5-4 downshift. tomorrow picking it up with a new SCIII

I slipped with the 85 hp, had it in only for about 2 weeks, but had 65 hp in for 2 years. Passing a semi and the 5-4 downshift. tomorrow picking it up with a new SCIII


was it on 65hp when passing the semi or 85hp still???

65hp for 2 years. Then 85 hp for the last two weeks. At the end of second week is when it slipped when I was passing the semi. I could tell with the 65 that it wasn't as strong as when I first put the tune in but thought that I was just used to it.

Dang that really sucks!! Can't believe they slip that easy! Besides buyin a full blown billet trans is there anyway to eliminate that shift problem?

Dang that really sucks!! Can't believe they slip that easy! Besides buyin a full blown billet trans is there anyway to eliminate that shift problem?

Yes and No... My advice is don't play with that 85 tune racing until you have half a built tranny saved up.

You can prolong the life at the 85hp tune by locking the truck out of overdrive. When you need that 5th gear, (NEVER get hard on the throttle in that gear.) downshift the truck into 4th with the OD lockout switch and make your pass... Put the truck back into 5th when your off the throttle.

Its really embarassing when you pull out to pass some ricer, you get up beside him and your tranny limps you.

Once you limp it once, it gets easier & easier to limp it the following times.

Would a transgo kit or anything help?

Would a transgo kit or anything help?

Yes, but in your Allison 5 speed, the tranny must be removed to install the Transgo Kit. If you are spending the 1000 bucks or so for R & R on the tranny, it would be foolish not to do the rest of the work while you are in there.

If you look in the vendors section, Mike L is offering a "Budget Tranny Kit"
It might be something worth looking at.

The stock convertor is a weak link also. So your real benefit is getting a triple disk convertor and a trans-go and it should handle everything the Predator can throw at it..........problem is.......unless you can do it yourself it's going to cost you $2500-$3000 totally installed (fluids, tax, and all). And you can get a full SCIII kit done for only about $1000 more...........so it just makes since to go ahead and get a full stage 3 kit..........or at least it did to me when I had mine done !!