spec'ing a shed hauler - axle ratio etc

[DVT873]

At the risk of getting shot, or banned I am going to mildly disagree on the Allison vs manual. First he stated fuel economy is not a major issue. The torque converter locks up in all the higher gears if not all of them. The last I looked at drive cycle data, especially urban/suburban, fuel economy difference was something like 1 or 2%. It sounds like this is going to be an urban/suburban drive cycle vs. OTR so a lot more shifting going between lights, intersections etc. His leg will like the auto at the end of the day.

I have been around medium-duty trucks for a long time. Most all of them have been Allisons since the mid-90s. Over time I have developed a lot of respect for those transmissions, especially the 2000 and 3000 series. I have seen them live in applications where I would have never speced them or would have speced heavier i.e. a 3000 vs a 2000.

When I was selling new I never had a single customer go back to manual after going auto. Virtually every garbage truck you see and a lot of smaller tandems, or tri-axles like 16 to 18 ft dump beds are automatics. Almost all Allison. I am not a fan of the automated manuals.

The electronics do an excellent job of protecting the trans without being a PIA about it. Follow the filter and lube change recommendations, use OE fluid and filters. IF he would wear it out, not likely in his application, the last 3000 series we put in was around 6K from Weller.

As far as a performance vs economy mode there will be a button that will let him choose. Default is usually for performance. All it does is change the shift points. About the only issue I've ever seen is with the right combination of grade, weight and speed the trans may "hunt" between 5th and 6th. If that happens select 5th until your over the hill or whatever.

Whoever is specing the truck SHOULD be able to provide with all the data he would ever want to see on ratio choices, gradability, etc., IF the salesperson is competent. Allison distributors used to have somebody on staff to do just that if the truck dealer wasn't providing the info.

On the exhaust brake aka potato in the tailpipe vs a tru Jake-type the exhaust brake works well when it is coupled with an automatic. Much better than with a manual. With a manual you barely feel it. The exhaust brake slows the engine's RPM quickly enough that the transmission downshifts. The downshifting is what slows the unit. It is very noticeable. Note that you have to tap the brake pedal or nothing happens.

All of the above is based on my experience with vocational equipment in the medium-duty category.