This feature in Pumper reports noteworthy conversations that take place at the Pumper Discussion Forum, an online forum for industry professionals found at www.pumper.com. Pumper Discussion enables exchange of information and ideas on septic and drainfield installation and maintenance, trucks and equipment, portable sanitation, chemical and additives and much more. Information and advice in “Overheard Online” is offered in good faith by industry professionals. However, readers should consult in depth with appropriate industry sources before applying such advice to a specific business situation.

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QUESTION

If you owned a truck with a standard transmission and switched to an Allison automatic, how did you like it? How does the Allison hold up? How many miles can you get out of it before rebuild? I am looking at a truck with an Allison and I’ve never driven one. I have heard not all of them are adaptable to a PTO pump. How can you tell?

ANSWERS

I have a 1989 with an Allison transmission. Other than the low gears, it is great. Off road or on grass, once you get a feel for letting the torque converter load up and get you moving, ease into the throttle until the truck starts to crawl without spinning. Downhill is a bit different. Also you don’t get the positive braking feel of a standard transmission, but once you get the feel, it brakes as well as a standard. For a lot of guys it is a love or hate thing. I love mine. As far as PTO-adaptable, call the local Allison shop and they should be able to tell you. Also, if you pull the PTO cover off, there will or will not be a gear visible. As far as longevity, it is all in the driver. My truck still has the original trans with no sign of needing a rebuild. I have seen Allison transmissions outlive the truck and seen them blow up in the first year. Mostly they hold up well. They don’t like tire-spinning or quick change of direction under load.

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I have an MT635 transmission, and the PTO mounts on the right and appears to be the same as any other PTO. As for fuel mileage, l have never had a 4,000-gallon tanker get much better than 4 mpg working around town. When I am running empty any distance, I have seen 6 mpg when empty on the highway.

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In my opinion, the Allison is the only way to go. It is smarter than the driver. It knows exactly when to shift, it never misses a gear and there is no clutch to go bad. The very best testimonials for Allison are the millions of school buses and all the millions of military vehicles running them. The easiest way to know if they will take a PTO is to look for the letters RDS at the end of the model number. If you find a truck you like but it doesn’t have an RDS transmission, any Allison dealer can install the gear that makes it PTO ready.

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I come from a long family history in the trucking business. I was in trucking before septic service. Overall, I do not like auto transmissions. The truck will get less mpg and maintenance is a lot more, plus the overall cost of the automatic is higher. My all-time favorite is a 13-speed transmission. My background is all from dump trucks hauling out of the quarry. The clutch is almost shot on my Mack with 225,000 miles. The price to replace my clutch is $1,800. Not too bad if you ask me.

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My experience with a Ford dump truck with automatic is if you got in soft dirt it would hardly pull itself. Even on level ground, if I was pulling a dozer or backhoe, I have had to unload it many times. That’s why I was interested how it would work on a septic truck.

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Most (septic service drivers) are using medium-duty trucks with transmission options being five-, six-, seven-speed standard shift or various Allison automatics. The smaller transmissions that I speak of in the medium-duty trucks make going with the Allison a no-brainer. If you’re going to run a 33,000-pound GVW truck or under you will absolutely be much happier with the Allison.