QUESTIONS FOR THE WEAVEMEISTER

Doggie Daddy · Mar 8, 2004

Weave, As you know, we have the International 7400 with DT530 Allison 6-speed. This truck has 5.63 rear-end gears. While we love the way the truck accelerates, the fuel mileage is horrendous. Our last truck was an FL-70 (8.3 cummins, 7-speed), this truck got app. 10 to 11 mpg. Our International barely gets 7 mpg (less in 70mph states). I have gotten estimates fron the local IH dealer on changing the gear ratio, $3350 for 3.91 gears and $3450 for 4.10 gears. Using my flawed math, I've figured that the difference between 7 and 10 mpg coule be app. $7800 per yr (figuring 120k per yr @ an average $1.52 per gal). I realize that 10 mpg might be wishful thinking with the automatic, but the point is that any improvement in mpg would pay for the gear change in a very short time. One of my questions would be do you think that by changing to the 3.91 that it would turn this truck into a "dog"? Also, do you think that the gearing in the transmission would also have to be changed? I do not know why this truck was spec'd this way as it appears that it is not set up for the job that it is doing. I suspect that it wasn't spec'd at all but rather it was included in some sort of special deal from IH to the company that put the truck together and that these chassis were not built specifically for expediting, but for some other purpose i.e. dump truck. I won't name the company that put the truck together but it rhymes with "A GLOOMY DUNK"!!!!!!:7 :7 :7 :7 :7 :7 :7 :7
Another question would be has your Dad had any problems with the electrics on his truck, specifically fuel tank sensors and instrument cluster? These are problems that IH knows about on the 7400/7500 series but their position on it is not to replace these parts until they fail. Thanks for any advice you can give us. DDx2

Weave · Mar 8, 2004

I'll start with your last question first. My dad was still home so I saw this and discussed it with him.
Yes, the fuel level sensors have been a problem. He has had his replaced twice, and needs to have them done again. IH still hasn't come up with ones that work right, but they have been addressed under warranty. He has not had any problems with the instrument cluster. In fact, those sensors have been the only problem(s) the truck has been into the dealer for. No permanent solutuion yet.
My dad's truck has the DT466 215HP w/Allison and 4.10 rear axle. He says the truck is getting 9.x MPG, but keep in mind it's a little 18 footer and doesn't weigh much.
The DT530 engine is tuned for a lot of low end torque, and not so much high RPM HP. I totally agree I think you have the wrong rear axle ratio for the highway. Your current setup sounds like how they spec the 7400 w/530 for snowplows with the auto and high rear ratio for max torque. Snowplows and small dump trucks are the chassis #1 application, and it probably came from IH that way.
By using a lower axle ratio, you'll lower the highway RPM and get the DT530 more into it's "sweet spot," which is making power at lower RPM's where it is most effecient. By going with the 4.10, you might very well get the truck into the 9 MPG range, making the swap well worth it over the time you own it. Does the 530 have the "go" for the 3.91? I'm not sure. My guess is it could handle it with the torque it makes, but it might make a few downshifts on long grades, and acceleration will be on the slow side. You won't be able to change anything inside the transmission, and won't have to.
Talk to a decent dealer about the choice on the axle to get some better figures on RPM's and cruising speed with your engine. I do agree with you that one of the lower ratios will get your truck's highway MPG more on the line where it should be, 'cause that 7 MPG and 5.63 just doesn't sound right.
-Weave-

x06col · Mar 10, 2004

DD
What does your tach show at 65mph? Where is your torque range?
I personnaly have my trucks running 16-1700 rpm at 65. Mid torque
range at whatever you call highway speed.

Doggie Daddy · Mar 15, 2004

at 65 mph i am at about 2150-2200 rpm (kinda hard to pinpoint that 'cause the tach is also doing some weird things, but the dealer can not find any problems with that) i talked to the truck manufacturer and international today trying to get someone to listen to me concerning the gear ratio /fuel mileage problem, international says that there is no way that i can go with a 4.10 gearing as the truck would have a top end of 110mph and at normal cruising speed would never shift into high gear.their reasoning behind this is that the transmission is an overdrive model.i told the man that i was sceptical about the not going into high gear part because with the current setup i am into high gearin a very short distance, probably in less than 1/8 th of a mile. as for the 110mph, i said that its not like i am going to be driving at 110mph i just want the gearing to get my rpm's down to a more reasonable range at 60- 70 mph.the discussion is far from being over as far as i am concerned.(they are supposed to get back with me about it)weave,thanks for your advice on this, i'll let you know how it turns out. DD

tazman · Mar 16, 2004

Hi,

I talked to one of our diesel techs here who worked at an International dealer prior to coming over...

He agrees that you will be able to change over you gears to the 3.91 for better mileage and performance...especially if you are not running fully loaded all the time.....

He also indicated that they run the computer programs on the engine and re-tune to the new gears.....this should also reset the Allison trans set-up...be sure they perform this when you have the work done.

The higher gears should be ordered for dump trucks running hard-heavy loads short distances or plow-trucks ( as mentioned before ).....
There is a build program that you use when specing a truck to ask these types of questions and will then recommend the proper engine/trans/rear setup.....sounds like they mis-matched the truck when they got the chassis.....

Hope this helps...

Frank in Pa.

P.S. - When you spend this kind of money on a truck...as a rep I would ask the dealer or the salesman for some assistance on the pricing.....They should have asked you these questions ahead of time
Perhaps you can speak to the dealer principal about getting a discount....????? It can't hurt to try...
"The Beast in the East"

dieseldiva · Mar 16, 2004

Tazman, that's some really good "stuff" you've brought to the table!! Doggie Daddy will be along later to comment, I'm sure. Thank you so much.

Of all the things I've lost in my life, I think I miss my mind the most!!

Doggie Daddy · Mar 17, 2004

thanks for the great info tazman.the estimate that i got for changing out the ring and pinion also included a $140.00 charge for reprograming the trucks computer.the person that i talked to from IH said that he didn't think that they would go below a 4.88 gear, because of the top speed factor. in my opinion i would think that by reprograming the computer that they could go with a 4.10 or 3.91 and then set the computer to limit the top end speed. again, thanks for the reply. DD

teacel · Mar 20, 2004

This site may be of some help:
[link:www.expeditersonline.com/cgi-bin/classifieds/classifieds.cgi?db=general&website=&language=&session_key=405c5d2739ed0607&search_and_display_db_button=on&results_format=long&db_id=6&query=retrieval|Click Here!]
His site is in the ad!!!
Maybe he can confirm or add more info! Good Luck DDx2

RichM · Mar 20, 2004

7 MPG is a real bummer these days,sound to me like you got a Dump or Tow Truck power train.A Bunk likes to say they deal with Expediters every day and know the business.Well 7 mpg doesn!t cut it in the expedite business. In my opinion they should change out the rear gearing for free.

guest · Mar 21, 2004

Rich couldn't have said it better. It seems that buying anything these is a gamble only to the customer. Once the dealer gets it sold, it's your problem. If they are going to be in the business of selling these trucks and pre-spec'ing them, they should stand behind it. 7 MPG sucks..to put it mildly... and they know that. I'm afraid that I would loose it if I were DD or some of the folks with the Mercedes engines that are giving so much trouble. Anyone who shells out $75-100K or more deserves much, much better equipment than these folks have recieved.

It would be bad enough if DD had bought this truck from a dealer that wasn't experienced with expedite equipment, but these people are not only experienced, they specialize in it. I would think personal pride in your business would be enough to warrant the attention that DD obviously deserves.

DD, if I were you, somebody wouldn't get a good nights sleep until something was done to improve the fuel mileage on that truck. They have phones and my guess is that they home telephones. My experience is that a phone call or 3 or 4 in the middle of the night to let someone know that your still unsatisfied gets the point across very well

.

I held off posting on this thread as long as I could..lol. I knew i couldn't be nice.

Best of luck DD, I hope you get something worked out.

teacel · Mar 21, 2004

I AGREE 100% My guess is that AB got a deal on this truck built and spec… for a dump truck buy the manufacturer. Because of what they do AB should have known or if they didn’t know should stand by their reputation and correct the problem. But before we all go flying off the handle and pointing fingers at AB did you even call and discuss it with them???

dieseldiva · Mar 21, 2004

Well guys I hardly know where to start. We made a promise to someone concerning our public writing on this issue and that promise has now been fulfilled so you'll probably be hearing more and more about it as we go forward. I am more the "mouth" of the family and Jim is pretty quiet however he's starting to steam up on this issue and I don't look for him to be silent much longer. He has been back and forth on the phone to AB and International and so far no one can decide what if anything is going to be done. I don't want to get too deep into this as I feel like he should post most of the stuff concerning the truck and he is out doing solo right now while I take care of some business here at home. Just wanted you all to know we're not sitting down on this one.
What I DO want to say and I mean this from the bottom of my heart, I am so moved by the concern and the comments from our friends here on the forum. It is no nice to know that you have good folks that are in your corner and I know when Jim gets home and reads this he'll be pleased too. Thank you all so much for your support, it means the world to us.
We'll post more about this as time goes on and I would like you all to know that we are not in this alone, more and more we're meeting up with people on the road that are having the same problems and frustrations with getting things done. We are communicating with these people on a regular basis and trying to stay on top of everyone's situation so we can all stick together. Enough said. We'll keep you posted. DDx2

Of all the things I've lost in my life, I think I miss my mind the most!!

SHARP327 · Mar 22, 2004

WELL AB IS ABOUT TO START HEARING FROM ME TOO! I'VE BEEN SITTING BACK LONG ENOUGH JUST TAKING IN WHAT DDX2 HAS BEEN GOING THROUGH AND EVEN THOUGH I'VE BEEN TRYING TO KEEP MY MPH DOWN MY FUEL USAGE IS REALLY STARTING TO HURT! AND WITH THESE FUEL PRICES IT'S KILLING MY CENTS PER MILE!

ENOUGH IS ENOUGH! TAKE CARE OUT THERE! SHARP327

Doggie Daddy · Mar 29, 2004

i was at the MATS on saturday, and the AB guys were nowhere to be found.from what i hear they had a very limited prescence at the show. hmmmm, could the handwriting be on the wall? by the way, this was my first time at MATS but by no means will it be my last. to put it mildly, it is AWESOME!!! worlds largest "candy" store for truckers. if you have not been to this show you have got to check it out. also, it was good to see you again lawrence and nice meeting you debbie.DD