Help! Allison transmission control problem!

[truk4u]

Michael,

Divide your scale weights by 2 per axle, then use the dual numbers for the drive and single numbers for the tag and steer. Here's an example:

Steer - 15,340/2=7,670 Use the single weight from tire chart
Drive - 19,580/2=9,790 Use the dual weight from the tire chart
Tag - 15,060/2=7,530 Use the single weight from the tire chart

I know nothing about Firestones, but be sure your not exceeding the tire pressures for the weight. Look at the max pressure numbers on the tires. Also remember, your tire pressures are going to really increase when they get hot, so it's important that you don't put in too much air when cold.

On your way home, stop at exit 306 and re-weigh at the Q-T Truckstop. If they're not busy, you can weigh each wheel position by moving off the scale with each side of the bus. The concrete apron is wide enough to weigh one side then circle around and weigh the other side. Make sure someone is outside helping so your sure to split the axles evenly and not get bad readings. On any of the scales, you can screw up and not get the axles split evenly on each independent scale platform. Also, are you sure your toad didn't end up on your tag axle scale ticket? Always unhook the toad.

[michaeldterry]

Tom - thanks for spelling it out for me! By George, I think I've got it! (finally!!!) I intend to follow your instructions to the letter tomorrow on the way home and will post the results tomorrow night after we get home.

[garyde]

Gary - I get the whole "inflating a few lbs more than the chart" thing - makes sense. I'm still struggling with making sure I'm reading the charts right and how to compare my axle weight numbers from the weigh ticket to make sure I'm comparing "apples to apples" (dividing axle weight numbers by 2 or 4 depending on which axle to get indivual tire weight numbers?).

Also, I'm going to take Steve Bennett's recommendation and get the bus re-weighed at a different scale on the way home tomorrow to validate the weight numbers I have now. I'll do it in two passes - once by individual axle and next weighing the bus in total.

Divide your weight by two not four on the drive wheels. So ,if you overall weight on the drive is say 19500 lbs, you would look for 8750 lbs on the chart under duals. If you read the instructions at the top, it indicates weighing each tire individually. If say one of the front tires weighs more than the other on the front, use the heavier weight for air pressure on using the chart.

[Larry W]

Just my two cents on getting the wieght for eaxh axle. I use a truck scale at a local farmers COOP store that has a flat approch and exit. I put the front axle on the scale, record the wieght then move forward so the drives are also on the scale and record the wieght of the two axles. Last I put all the axles on the scale. This gives the total wieght. Then do the math to detremine the wieght of each axle. I think using a scale with a flat approach and exit is very important. Ever notice when stopped on a less than level spot how the tires on the low side of the coach willl look low on pressure due to the additional load cause by the coach not being level.

[Larry W]

Forgot to say. My 99 XLV chassis has a Prevost weight and inflation plate on the inside of the rear engine door on the passenger side.

[Jon Wehrenberg]

Larry et al,

The inflation pressures recommended by Prevost or the converter are at best starting points until you can get your coach weighed with all your stuff on board.

The only correct way to learn inflation pressures is to get your coach weighed with full fuel, full water, all your normal stuff on board.

[Ray Davis]

A little caution here. IN looking at both the Firestone tables, and the Michelin tables, they are reported differently.

The Firestone tables (which match the tires that Michael has) give weights per wheel, even under the used as a dual section.

The Michelin tables, however don't, and the weights are listed for both tires combined as a dual axle. So, Tom and Gary's suggestion works fine if you're looking at the Michelin tables. If you're looking at the Firestone tables, a divide by 4 is needed.

Ray

[michaeldterry]

A little caution here. IN looking at both the Firestone tables, and the Michelin tables, they are reported differently.

The Firestone tables (which match the tires that Michael has) give weights per wheel, even under the used as a dual section.

The Michelin tables, however don't, and the weights are listed for both tires combined as a dual axle. So, Tom and Gary's suggestion works fine if you're looking at the Michelin tables. If you're looking at the Firestone tables, a divide by 4 is needed.

Ray

Good catch, Ray! Thanks for saving me from a potentially serious error (I'm using the Firestone tables that correspond with my new Firestone FS 400's)! As they say - "ignorance is bliss" and I'm downright giddy with bliss!

[michaeldterry]

I stopped at the QT Truck Stop at exit 306 on the way home, as recommended by Tom to have the bus reweighed with the toad unhooked. for more accuracy, I filled my fresh water tank before leaving Chattanooga this morning and topped off the fuel tanks at the QT before weighing. Vita went inside and explained to the "Weigh Master" what we were trying to accomplish. He understood exactly what we were trying to do, but unfortunately, the CAT scales have a metal framework over them that holds up the CAT Scale sign and the intercom box that allows the driver to talk to the Weigh Master. The frame is very close to the edge of the scale pads and prevents you from weighing one side or tire position at a time. Also, he said that because of the way the bus axles are configured that the Cat Scales are not set up to give accurate separate weights per axle on the drive and steer axles (the steer and tag axles are too close together). He recommended weighing the bus in total and the weigh ticket would reflect a separate weight for the steer axle and the combined weight of the drive and tag axles. He then said to take our weight ticket from Saturday from the Pilot Truckstop and subtract the drive axle weight on the Pilot ticket from the combined weight on the QT ticket to get the actual tag axle weight.

Here's the good news: on the QT scales, with full fuel, full fresh water, golf cart in the front bay, approximately 600 lbs of human cargo (two teen girls asleep in the back and one overweight driver - Vita was outside directing me onto the scales), two small Shih Tzu dogs weighing a total of 18 lbs, and various and sundry clothes, food, toiletries and personal electronic gadgets - the bus weighed a total of 47, 060 (only 60 lbs over the data plate GVWR numbers)!

The steer axle was 15,220 lbs.
The combined drive and tag axles were 31,840 lbs.
Total Gross Weight was 47,060 lbs.

Now, if I do what the Weigh Master suggested and subtract the drive axle weight from the combined drive/tag weight, (31,840 - 19,580), I get 12,260 lbs. for the tag axle! This is much closer in line with whats on the data plate!

Data Plate numbers:
•Steer axle - 14,600 lbs
•Drive axle - 20,400 lbs
•Tag axle - 12,000 lbs
•Gross weight - 47,000 lbs

Now, all I've got to do is make sure that my actual tire inflation is the correct psi for what the chart recommends! Whoopee!

As far as the weight difference from Saturday to Monday - all I can figure is the the toad somehow was on the scale pad at the Pilot scales and got included in the weight.

[Ray Davis]

I'm not sure I understand. This time you weighed the tag and drives combined, and you are subtracting the weight of the drives from previous weighing? I'm not sure I would do that. I guess it's a pretty good estimate, but.

When I've weighed at these CAT scales, I've been able to split the drive and tag onto separate parts of the scale. Obviously this is prone to some degree of error as it's really hard to get this situated so that you get an accurate weight.

But, I'm glad your overall weight came down.