Torque down in 5th gear

[rickdlance]

I read that the torque on the new LLY is backed down in 5th with the allison. I just bought a truck today and the literature states 590 foot pounds of torque. Does somebody know where I can find this backdown in print. I would be very unhappy if my new truck does not deliver advertised power.

[OC_DMAX]

Look in the LLY update article that was posted in March on The Diesel Page. It indicates the new uprated power levels are only applied in gears 2,3 & 4. Gears 1 & 2 remain the same rating as the LB7.

Reference the article here:

http://www.thedieselpage.com/duramax/lly2004.htm

I am certain companies like Edge, etc will address this issue.

[DURA-MAX3]

I wish i had known that before, I just told my local dealer to go get a new truck that i am going to buy if it is ok...I did not know that the power was set up like that...How stupid...

[JB6600]

That would be 1st and 5th.........and I doubt you could tell it..........JB.

[rickdlance]

I pull 28,000 pounds thru the mountains once a month. 70 foot pounds of torque would be noticed. I know I can tell a big diferance when I kick the Attitude up 1 setting.

[rickdlance]

That is gross vehicle weight, before anybody asks.

[OC_DMAX]

Total torque is not the only thing to consider, but also where the torque is made. You would need to overlay the measured LB7 & LLY torque curves (as measured in 5th gear) and take a look at (say 2000 rpm) where you do most of the real pulling. Then look for the difference.

Looks like you have the Juice on your other trucks, so once a box is available for the LLY you will be all set.

[More Power]

Interstate overpasses, rolling hills or headwinds would produce the same felt power and frequency of downshifting as a stock LB7 when running in 5th. I doubt anyone will notice a lack of power in 1st.

While in the mountains and heavily loaded, the Allison transmission will spend more of its time in 3rd-4th gears where the LLY power increase will be available.

MP

[JoeyD]

It does seem odd they would limit power in 5th. It would be very usefull in avoilding a downshift as 5th gear at highway speeds is where max tq is rated.

[JB6600]

I think the torque does come in earlier though........at 1600 rpm's instead of 1800...........JB.

[k30]

I've yet to see any factual proof from articles on here or press releases from GM that this "power down" in 5th and 1st actually occurs.Everything I've read says that its "rumored" or "sources say". I would like to here from a tech that knows for a fact whether or not this is an actual feature and has some sort of proof to back it up.

[More Power]

Sources also indicate that the ZF LLY is operating at LB7 levels in all gears.

We report - you decide.

MP

[k30]

The ZF rating is official and has been verified in documents by GM while the 1st and 5th issue has not.

[More Power]

I was the first automotive journalist to tour the DMAX engine production facility in March of 2001. The illustrated article that appeared in Truck Trend magazine a few months later was the first published about (that showed) DMAX engine production. I managed to get a TDP member tour of the DMAX and GEP engine production plants later that year during the 2001 TDP Rendezvous. Representatives from DMAX, GM, AM General, Isuzu and Allison were in attendance to talk to our group.

GM has helped sponsor TDP's current Duramax Diesel Power Project truck.
http://www.thedieselpage.com/features/project2-5.htm

We have dozens of GM, AM General (GEP), Isuzu and Allison (or their subsidiaries) employees as TDP members.

Editorial policy here at The Diesel Page is not to divulge sensitive information that has been embargoed or related to me "off the record". In addition, it is our policy not to divulge information sources that might jeopardize someone's career.

Now, you can choose to believe the LLY power specs I've published or not. That's your choice. Just remember, you read it here first.

MP

[DmaxMaverick]

....Not to mention ethics.

We can't all be lawyers.

[k30]

I'm not saying that the I believe that this alternate power rating does not exist, I just find it odd that there is no concrete evidence to back it up so far.Yes, this is a credible site and I wouldn't post here or read your articles if I thought otherwise, but I am simply interested in whether or not this "power down" feature really exists as I have found no evidence thus far to prove that theory. I appologize if it sounds like I am questioning anyones credibility I would just like to find out once and for all if this is true because it would seem that a drop in 70 ft/lbs of torque in 5th gear would be quite noticeable especilly when towing.

[More Power]

Hey K30... I'm with you.. Till GM officially publishes the data, it will remain a "reported" power/torque rating - for the different Allison gears. GM has surprised me in the past, but I think these "reports" are pretty solid.

Rumors are that we'll be all smiles in 2005...... ;)

MP

[dmaxmule]

More Power
What are the rumors for 2005 that you are refering to? :confused: I am Debating on wether to change my order to an allison or leave it as a zf 6. :confused: Dealer says most likely my truck will not be built till then anyhow. :rolleyes: It is just a few weeks away till 2005's hit production. :D

[rickdlance]

I now have the 2004 truck and compared to both my 2001 Dmax's its a dog. Only 200 miles so far. I hope it gets better. A BUNCH BETTER.

[rickdlance]

I now have 27,000 on the LLY. Still a dog and poor fuel mileage to boot. GM customer service promises to do something soon.

[Mile Hi Guy]

Rick
Is GM listening to your complaints or is the fact that it starts and stays running have them saying that it is fine? Mine is doggy too and the mileage is below the 6.0 GM gassers in our fleet here at work. :(

I positively cannot stand the way it takes off from a stop. It's does not smoke and that is probably the primary goal.

MP
I don't think anyone is questioning your call on power levels, but it seems odd that GM does not disclose this in the literature. Mazda/Ford is going through a problem right now because the first RX-8's have 15 or so less hp than advertised.

Thanks for listening.

[ 06-19-2004, 06:19 AM: Message edited by: Mile Hi Guy ]

[rickdlance]

Still waiting on GM to make a decision. 3 people have driven the truck towing and all 3 say it seems to go limp sometimes. The turbo goes dead, the power goes down, the temp goes up and the fuel gage goes down. When this happens it will have trouble running the speed limit on level ground. No reason and no way to tell when it will go back to normal, which still won't keep up with my 01 with the Juice off towing. They do seem to have solved the downshifting out of 5th gear, maybe a little too much.

[rickdlance]

GM called today with bad news. They know they have a problem, they don't know how to fix it, and I have to live with it. If this is what being loyal to GM is all about I will own 3 Dodge or 3 Ford trucks within the week.

[More Power]

Do this:

Take the truck to the dealer and request that they contact the General Motors Technical Assistance Center. The Technical Assistance Center will start a case for your truck, and will work with the dealer and technician(s) to resolve the problem. If they (GM-TAC) need help, they contact a group of Powertrain engineers who deal specifically with the Duramax.

This situation is resolvable.

MP

[rickdlance]

I have already done that. I have a case file.

[Mark Heiken]

When I had a 6.5 with a case file on it, it made no difference on the support from GM. The service manager at my dealer got a total of one phone call on the problem. The service manager called 3 to 5 times a week to try to get help. I finally got GM to trade me into a new rig on what I felt was fair terms.

[More Power]

Rick,

Send me an email message. I have one more approach to try.

MP