Is anyone making headway on the defuel/delayed shifts for the lly's. I've spoke with a guy with a SC stage 5 and with people with other variations of aftermarket parts, and haven't heard of a happy customer, that are running high HP, yet.

My truck shifted great in spokane after getting the tranny put into fast learn from a tech 2, hence the 13.04. I drove around all week in the city and did some pulling, then went to the strip. Truck shifted like crap, delayed defueled shifts, was at least .5 off in the quarter mile times.

This problem is driving me nuts, and takes alot of fun out of dragracing. I'm ready to spend the money needed for a fix, and wondering if anyones made advances into the problem.

Thanks for your thoughts,
Rob

Mine shifts very well. What are you running for programming? I find this makes a huge difference. I drive mine like I am at the races all the time. I think that helps a lot as well. Maybe I am not big enough HP to have problems.

Just out of curiousity, do you change programming around (i.e, change tuners, etc. frequently)?

I was towing for about 5 days and loaded up the hot tunes when I got home. Truck was shifting akward, but I gave it sometime to learn. Well, apparently it didn't learn enough (after about 10-20, 0-70mph, half throttle runs) and was flaring the 4-5, then later on, decided to flare the 3-4.:rolleyes: Tried making it learn again; samething. I tried the copilot, still flaring 4-5. Before the trip, truck was shifting flawlessly, but I couldn't tow with all the power (EGT's would skyrocket).

I'm on the same boat with you, Rob. Good luck!

I try to keep it in the highest tune all the time. I find that helps A LOT. I only drop it down when I tow and I try to keep the shifts to a minimum.

I've been running with ppe on max setting for along time. I towed and drove like that all week. I do drive pretty aggressive also. With the twins I've been able to keep everything on kill and still tow and drive with min. smoke. Might be the tuner, but I don't change settings often. Others running the predator/va stack that I've spoken with, have the same issues.

05 2500hd, has the co-pilot helped? I'd pick one up, but I've heard mixed reviews on the lly.

All this time I've been questioning my set-up, but after running a few 1/4 mile passes with the tech 2, I'm not seeing any slippage. I don't think the defuel is due to slippage:help2:

Currently I would not recommend anything sold for LLY Allisons with more than 450rwhp. Neither the Suncoast or ATS will hold big power reliabilily. Sure you can run awhile, but the results are unpredicable. That is my opinion, based on running both transmissions and watching others in the same boat.

Has anyone with a Co-Pilot suffered this condition?

I had zero luck with the CoPilot improving either a stock LLY transmission or a ATS trans. It "feels" like it does something, but track results show nothing.

05 2500hd, has the co-pilot helped? I'd pick one up, but I've heard mixed reviews on the lly.



Rob, copilot does firm up shifts, but I haven't been back to the track in a while to see any 'improved' results. Just last week, it felt pretty strong, but I'll have to wait til Saturday to get any track results.

Do you think there will be a fix out for the LLY transmissions anytime soon?

I've gotten a few emails since I posted. I need to clarify:

If you are not dragracing constantly with over 450RWHP, you should be fine with the current offerings. We have a SCIII in Blue with over 20,000mi on it, and it has never limped even with ~560rwhp (nitrous). With over 450rwhp, you will start to see flaring and erratic shifting.

For guys running stacked tuners with no N20 and stock turbos, you will be fine. Didn't mean to panic anyone. We are just now seeing the kind of power that causes this behavior, so it might take awhile to find a solution.

For guys running stacked tuners with no N20 and stock turbos, you will be fine. Didn't mean to panic anyone. We are just now seeing the kind of power that causes this behavior, so it might take awhile to find a solution.

So true, I have no issues with my tranny on the street or with heavy towing. I've never limped it or had any problems beating it like a red headed step child on the street.

What is the difference between a LB7 alli and a LLY alli? The only difference I know of(very limited knowledge) is the pump and housing. Can the converter lock out valve in the LB7 alli's be the difference?

Rob,

Have you tried resetting the tap cells and into fast learn right before you get to the track then make a couple of mild bonzai runs?

I had zero luck with the CoPilot improving either a stock LLY transmission or a ATS trans. It "feels" like it does something, but track results show nothing.My truck was 3 tenths of a second slower last at the track last Friday. Because my CoPilot controller took a dump.

Trip, I did reset and fast learn last weekend with a loaned tech2. It worked great, the tranny shifted awesome. I don't have a tech2 available though, and haven't found anything that works besides that. My ppe says that it resets the tranny, but it doesen't seem to do anything.

Maybe I need to buy a tech 2, but that is a lot of money to get the tranny to shift right. I'm getting desperate, so maybe a tech2 is a good buy.

Trip, I did reset and fast learn last weekend with a loaned tech2. It worked great, the tranny shifted awesome. I don't have a tech2 available though, and haven't found anything that works besides that. My ppe says that it resets the tranny, but it doesen't seem to do anything.

Maybe I need to buy a tech 2, but that is a lot of money to get the tranny to shift right. I'm getting desperate, so maybe a tech2 is a good buy.

Does everyone think it's a software issue, or a pressure issue? After fast learning with the tech2, I'm leaning towards software, or does the fast learn change the pressure on shift points?

Are the TCM's different between the LB7 and LLY? Could it be the TCM? Can you swap them? Could the TCM also be why the LLY lays over in 5th?

How are LB7 guys getting 700 RWHP out of their Suncoast Ally's??? And LLY guys can only get 450 RWHP reliably!? Should I wait out on getting my Suncoast IV and see if someone comes out with a better tranny fix? Or should I just do it now. I feel like im gonna buy a SC IV and then the next day they will come out with the Suncoast VI..."the perfect tranny that doesnt lay down in the LLY!!!"

---Ben

im waitin'

I am thinking I may wait too till this is all sorted out

Could it maybe be that with an Edge boost alert set low, that while under hard acceleration boost is reaching max and Edge is defueling.

Jason

In this case no. Idaho Rob is running the PPE. IIRC he will stack with the VA also.

Currently I would not recommend anything sold for LLY Allisons with more than 450rwhp. Neither the Suncoast or ATS will hold big power reliabilily. Sure you can run awhile, but the results are unpredicable. That is my opinion, based on running both transmissions and watching others in the same boat.

McRat,

Your opinion is 100% wrong. LLY tranny can be modified for same capacity as LB7 but it takes more than a SC III clutch pak.
Smoop

McRat,

Your opinion is 100% wrong. LLY tranny can be modified for same capacity as LB7 but it takes more than a SC III clutch pak.
Smoop

Are you not seeing the "layover" issue in 5th on the LLYs with your IV and V kits?

No one that I am aware of has proved that the layover is transmission related. We also don't know if it is a result of slipage or just a fluke of some sort. Unless I missed something.

Are you not seeing the "layover" issue in 5th on the LLYs with your IV and V kits?

What he is trying to say is that with the correct selection of parts, the "LLY" trans can be made just as strong as the "LB7" trans. It just takes a bit more than a kit.

My LLY has the std stage IV Suncoast in it and it is holding fine so far. I haven't tested it extremely hard, but should be in legitimate uncorrected 450+RWHP range.

Not that I am an expert by any means...but Im inclined to think it all has to do with the TCM software written for the LLY's (remember since the LLY's have more power than LB7's, they are instructed to defuel to LB7-power levels in 5th gear). Wouldnt this be exactly what is causing the lay-down in 5th gear? Anyone tried installing an 01-04 LB7 TCM into an LLY???

---Ben

McRat,

Your opinion is 100% wrong. LLY tranny can be modified for same capacity as LB7 but it takes more than a SC III clutch pak.
Smoop

Thanks for chiming in. Good to have some experts give their imput. The parts your talking about, maybe the LB7 pump and housing, do you sell them?

My thoughts on the variables:

Tuner causing problem - I don't think so, using tech 2 and fast learn, trans temperarily fixed shifting problem.

Trans slipping causing defuel - I ran the tech 2 on snap shot for three 1/4 mile runs, and didn't see any slippage, but I'm new to a tech 2, and the truck shifted great when tech 2 was attached.

Pressure/pump difference between the lly/lb7 trannys - Not sure on this one, if that's the problem, why would it shift great for 7-8runs after putting in fast learn.

TCM - ?. Isn't the co-pilot supposed to fool it, if so, why isn't it working on the lly trannys.

I know very little about these trannys and their operating systems. Please correct me where needed, I'm just running things through my head.

My fifth gear lay downs almost gone after installing a lift pump, I sometimes still get a slight flat line right at the end of my run. I need to check rail pressure next time.

McRat,

Your opinion is 100% wrong. LLY tranny can be modified for same capacity as LB7 but it takes more than a SC III clutch pak.
Smoop

My opinion is based purely on experience. I'm willing to try anything.

I have the complete tech documents and specifications of all the Allison tranny's, including the new MW7 6-speed. Line pressure, pump pressure, clutch specs, and speeds at which clutch packs come on-line and disengage are IDENTICAL. ~260 PSI is the max line pressure (stock). Obviously I could not get any info on TCM software though because Allison hoards that away and doesnt even let GM or dealers know.

---Ben

Ben,

What about the lockup valve that is installed on the lb7 aftermarket trannys, and not the llys. I think this increases line pressure to the clutches when converter is locked up. So when the lly converter locks, there is less line pressure to the clutches, yes?

How much boost are you guys seeing before/after laydown?

Off hand I don't know but definately less boost and less fuel.

hmmmm ill have to dig around and look for the line pressure when the TCC is locked up. So when I get my Suncoast IV done, cant I just have them install an LB7 lockup valve??

---ben

You'd have to go to a Suncoast V to get that done...

You'd have to go to a Suncoast V to get that done...

Is that because they're giving a LB7 tranny with the stage 5? As far as I've heard no one makes a lockup valve for a lly tranny, and if you want the benefits you need to swap out the pump/housing from a LB7, and what happens when all the cores are 04.5 and newer lly's

LLY pump is different and it handles the cutback in a different manner, that's why there is no valve avail.

Cutback/lower line pressure will not cause a laydown, it cant.

So if I got a Suncoast V...it would most likely be an LB7 core and therefore I would have no more laydown?

---Ben

Let clarify my problem, the few I've spoken with have the same issue.

Delayed/defueled feeling on shifts is my biggest problem. People who watch the truck run down the quarter can see the truck settle badly on the shifts. Fifth gear laydown happens sometimes, but not my biggest worry. Maybe the two are related?

Eric, any idea on what the problem is? I'm not seeing slippage on tech 2, same problem with different tuners, after a fast learn it shifted great for about 5-6 passes and then started to slowly get worse again.

I have spoken to someone with a SC stage 5 in their lly, and he is having the delayed shifts also.

Thanks,
Rob

LLY pump is different and it handles the cutback in a different manner, that's why there is no valve avail.

Cutback/lower line pressure will not cause a laydown, it cant.

Yes it can when it reads a slip which it probably will. it will pull fuel and timing. It will be subtle but it will happen.

Yes it can when it reads a slip which it probably will. it will pull fuel and timing. It will be subtle but it will happen.I do agree with that, I was just assuming that there was no slip.

I put an Extreme trans in an LLY and I dont know if he is getting that lay down or not, I dont think he has ever made a full run on it, uses it for truck pulling.

I though that the pullers werent having the same issues though as the drag racers?

I though that the pullers werent having the same issues though as the drag racers?

I think the issues is mostly 5th gear, shouldn't be an issue for the pullers

With the cost of fuel, that Ally is smart, by defueling it's saving you money.

Jason

Rob are you coming to Seattle this weekend, the T2 will be there.

Rob are you coming to Seattle this weekend, the T2 will be there.

Karl, I'd like a rematch. I've got the propane and N2O hooked up:D But... the bull elk are bugleing in the hills and my broadheads are sharp, so I'm off to shave some weight off my frame chasing critters.

Have fun, wish I was part of the trans-plant team, but looks like you have all the bases covered with opie:ro)

Good luck, and have fun this weekend,

Rob

After looking more at your run I think you should have been high 12's you were only 4 hundreths shy of it. Propane and N2O, no doubt you're going to send me packing.

Good luck on your hunt, I dont get to until Nov for elk. My brother went out last weekend and saw deer, elk and a big a$$ bear. He never got an arrow off though, it's his first archery season.

I have the SC V in the LLY that Rob is talking about.

I have horrible defueling at the track on Predator/VA/N2O passes.
The fuel pulls back enough that boost falls to less than 15 psi, and my N2O will shut off. I rarely get 5th gear laydown. The problem doesn't seem to get any better with repeated passes on the track. I don't have access to a tech 2. I drive around with the Pred/VA stack on high at all times.

I have never limped the SC V. The fluid has good color and smell and it is at the correct level. Other than high HP shifting I don't have any complaints.

I have not heard the LB7 guys complaining about the defuel problems. It seems that all tranny combinations in the LLYs can have the problem. We need to see if an LB7 TCM swap is possible. If there is anyone who has a workable solution I would love to hear about it.

I wish I would have bought an LB7. My attention span is just about exhausted. If I had submitted my order 1 week earlier, I would have gotten an LB7.

Mike

Are you running the Hot VA 130hp box?

There is only one VA available for the LLY (120 HP)

I seen an add on ebay for a "Hot" 130hp LLY box, that is why I asked.

We were unable to run at the strip yesterday after the dyno day (due to rain).

We went for a ride with the Tech2. PPE Hot+VA+N2O and... THE TRANSMISSION SHIFTED PERFECTLY.:wtf:

It was clicking off shifts no problem. It did it for 2 WOT runs.

There was no requested defueling on the Tech2.. There was no laydown.

I don't know what to think. Maybe its time for a race-only TCM. I have been flogging the truck for the last week and maybe it helped.

On edit: The only thing I did to the tranny was change the spin-on filter Friday afternoon.

Maybe having the tech2 hooked up scared it.:eek:

Well if a Tech 2 is successful in scaring it into shifting RIGHT and not laying down, then im in luck cause I have a Tech 2!! Well it should arrive in a few days...its still at the dealer getting the latest updates put on it. Ill have to do some research on how to use the durn thing first though...:rolleyes: They're not that hard to use right? I figure if the dealer can figure it out than they must be idiot proof.:) :rolleyes:

---Ben

We only had the Tech2 plugged in to watch for defuel/torque management. I really wish we could have run the 1/4.

If the TCC spils it will & P.S.I.=CLAMP LOAD
LOWER LINE PRESSURE = LOWER CLAMP LOAD
TOM
LLY pump is different and it handles the cutback in a different manner, that's why there is no valve avail.

Cutback/lower line pressure will not cause a laydown, it cant.

It seems like the lay down phenom has to be software related. I don't understand how a hard part would know to "Lay down" in 5th gear.

After reading all of this I can't remember if anyone saw any defueling on a tech 2, but generally that's all CAT does when they want to derate. Simply put an algorythm into the ecm and at a certain condition or criteria the engine derates and pulls fuel away.

I was recently a victim of the lay down, at least that is what it felt like. Truck ran fine until well into 5th, then it felt like I lifted off the throttle, and acceleration leveled off.

I was recently a victim of the lay down, at least that is what it felt like. Truck ran fine until well into 5th, then it felt like I lifted off the throttle, and acceleration leveled off.

Two different problems.

Lay down during shifts(takes forever to shift) and, fifth gear laydown(stops pulling hard in fifth)

The fifth gear lay down problem seems to be fixed by shimming the return valve. I haven't heard of anyone with the fifth gear laydown that shimmed their valve.

Defueled shifts are another problem that takes hard parts in the trans to increase line pressure. The fix seems to be available now.

If anyone needs any Tech 2 work/monitoring done on the truck, id be happy to help out and run tests/take snapshots with my tech 2. My tranny is stock, so it will probably always show some defuel, but we could see where its pulling back the most fuel. And I could also watch line pressures in 5th gear...

---Ben

Thanks Ben,

Funny thing with my stock tranny and a Predator on 100hp, the truck shifted great and I never had a 5th gear laydown. Although I was only running low 14's and 94mph.

The fifth gear laydown used to happen to me almost all the time. Right at about 100MPH the truck would flatline. After shimming, I've yet to have the problem. Truck pulls hard now all the way through the traps. Nothing else was changed.

what return valve are you referring to? Can you point me in the general direction for some info on shimming the relief valve?

The truck seemed to shift ok, I have nothing to really compare to. So I think it shifted some what quick for a stock ally.

http://dieselplace.com/forum/showthread.php?t=37711&highlight=shim

ok, that's the thread i was reading. Thanks for that, but those guys are all setting 1093's, I haven't set one of those since I put the finger stick on. And even when I layed down the tranny in 5th, last weekend, I still never set a code.

I just wanted to make sure that was the same problem?

after taking some allison classes at work i really believe that if someone could hack the tcm they could make the allison shift awesome. everytime i reset my trans from slow to fast it shifts perfectly. thats with a ppe hot and the edge attitude. i was thinking about looking for thicker trans fluid or some kind of additive to increase the viscosity when the trans fluid is cold my truck shifts awesome!

oh yeah and the bully dog shift kit is just a waste of money$$$. shifted hard for a while, the must just turn down the pressure to make it grandpa style. hmm

oh yeah and the bully dog shift kit is just a waste of money$$$. shifted hard for a while, the must just turn down the pressure to make it grandpa style. hmm

The alli learned about the high pressure and cuts it back.
Many have been told to burn the money vs getting the 'shift kit' ):h

after taking some allison classes at work i really believe that if someone could hack the tcm they could make the allison shift awesome. everytime i reset my trans from slow to fast it shifts perfectly. thats with a ppe hot and the edge attitude. i was thinking about looking for thicker trans fluid or some kind of additive to increase the viscosity when the trans fluid is cold my truck shifts awesome!

Thicker fluid will not help. Ally shifts more firm when cold because the TCM taps converter clutch on for a second during upshift, it is part of the cold program strategy.
mike

The cold shift is always more firm, but I attribute it to the reduced power of a cold engine. The Allison is simply expecting more power input than it is getting. This is ESPECIALLY true with the Edge as it is essentially off until you come up to operating temp.

Is the shim modification the correct fix for the 5th gear lay down?

The cold shift is always more firm, but I attribute it to the reduced power of a cold engine. The Allison is simply expecting more power input than it is getting. This is ESPECIALLY true with the Edge as it is essentially off until you come up to operating temp.

Never heard of such a thing. I can flip my switch to the extreme program when cold ( without relearn ) and it shifts firm. Allison DOC will show converter tap on every shift till warm. Tech 2 will not always show it . Check it out .

MIke Is right, i read about it on Allison's home page. It is programmed to shift like that for a faster warm up ( Diesel's only) Im have a problem w/defueling on shifts, cleared my taps and ran just fine,but put my programmer in and back to hard shifts and 3rd to 4th is very fast. I know this is the LLY fourm and i have the LB-7 but could you tell me why it wont defuel on its own,and has to have taps cleared?
Thanks, cody

Less power on a cold engine is a definite regardless of the program. The TCC thing is could also likely true although I'm not sure what the logic behind it would be. TCC lockup and overdirve is supposedly delayed as cold shift strategy to make more heat in the engine through increased RPM.

Just did some tests (PPE 90hp, Edge on 5) with the Tech 2 hooked up heres what I found... I saw not one bit of torque managment; it stayed at 0%. Slip RPM went up to about 20 RPM on locked shifts, and rolling into it HARD in 5th gear resulted in only about 10 RPM slippage for a couple seconds, then it dropped to about 1-2 RPM. At around 80 mph or so, the truck "popped" two or three times, and when it did this, I noticed the rail pressure dropped to 21,XXX PSI, down from the commanded 23055 PSI. It popped a LOT more with the twin KD pumps OFF, but still never threw a 1093...

Hope thats of some use to you guys...it seems I would definetly benifit from a shimmed releif valve to stop the rail pressure from dropping..

---Ben

Here is a picture of the Actual rail pressure vs. commanded rail pressure graph...you can see how the actual rail pressure is all over the place, but could this also be from my fuel pressure regulator thats crapping out???

---Ben

what do these trucks have on them for hepa pumps? Why does this only seem to happen in 5th gear? Is that the only gear we hold long enough to feel it? The engine doesn't know what gear it's in, so do we just not build that much rail pressure in the lower gears? Duratothemax, can you record some rail pressure runs as you go through the gears. I'm curious to see what rail pressure does while it shifts through the lower gears, and what it does when it lays down in 5th.


Generally we try to keep the rail pressure as high as possible usually 26.5kpsi. So why would they set the spring rates low enough the pop at 23kpsi, or is it just a poor manufacturing job of these relief valves?

The LB7 and LLY fuel rails max out at 23055 PSI IIRC...the LBZ will operate at up to 26,000 PSI I think...but the older engines are a lower max rail PSI..

---Ben

The problem with some of the springs I think is when they get hot, they expand/contract/soften etc.. and therefore their popping pressure changes.
Kappa-- The actual rail pressure stays pretty darn close to commanded rail pressure until ~80 mph or so in 5th gear, thats where it drops..why it only drops then as opposed to in other gears? Dont know...maybe since the engine is under more load in 5th gear, it requires even more fuel. I forgot to check injection rate (like actually how much fuel each injector is dumping in, which does not neccessarilly correspond with rail PSI)..but say for example, the engine is not under as much load in gears 1, 2, 3, and 4...the rail pressure may be up at its max of 23055 PSI, but the injection rate may not be way up because the engine isnt under as much load and does not require as much fuel to make the correct amount of power. Do you see what im getting at? Then 5th gear comes on, and engine load goes way up. Because the rail pressure is already at its max, the ECM responds by holding the injectors open longer and dumping more fuel in. This is where the problems start. The CP3 cant really supply enough fuel (especially without a lift pump) when the rail pressure is up AND the injector duration is lengthened. The injectors are just asking for too much VOLUME of fuel...and when the rail PSI is high and injector duration is high, there is so much fuel going thru the rail that it "pops" the valve.

That's what I was wondering if 5th gears just loads the engine harder or what. I guess my original question still remains.

Is this the right mod for 5th gear lay down. I haven't set any 1093's yet, so this is where I'm getting confused.

As I understand it, the releif valve can "flutter" allowing the pressure to drop, but not drop enough to throw a 1093.

---Ben