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Allison Diagnostic Plug-in
2005 Prevost Shell XLII, 2004 DD60
Where is the Allison transmission diagnostic plug-in location?? (i.e., where do you plug in the laptop?)
I’ve got an appointment with Clark Power Systems – Knoxville next week to change my Pre-Select downshift from 5th to 4th. I’m sure they know where to plug-in, but I don’t.
Thanks
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14 Replies
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One under dash left side and one in the rear under the electric box above engine if I remember correctly. These connectors are where everything gets read or programmed through….engine, tranny, antilock brake system etc. You need software for it, but they are all there.
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Why do you want it do go to 4th? Just curious. Usually a one gear downshift is going to work fine and you can manually downshift from that point. (That is why you are called a driver).
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Jon: Driver’s are overrated. I’ve been advised by my s/o that as soon as the self-driving Prevost is available, it and a divorce will be the order of the day.
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With Jon on this one…most people want it changed to 5th if they get one that is 4th. Very annoying to have it automatically go to 4th all the time. Geo.
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New, inexperienced driver in the family.
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Dropping a single gear is going to work fine and if you know your top speed in each gear as soon as your speed slows to that speed you can push the down arrow to engage the next lower gear, but if you drop into the lower gear at the top of its speed range, as the gears go lower each succeeding downshift becomes more harsh.
If you manually downshift you can lessen the abruptness of the shift by adding a little throttle as you downshift. If you program the downshift to lower gears like 4th as soon as your speed reaches the top speed in that gear it will downshift and then the entire gear train has rather harsh forces acting upon it while it tries to spin the engine up to 2100 RPM
If you want to know what it feels like take the coach on the road and let it shift into 6th. Slow down gradually without allowing a downshift. As soon as the speed gets to 54 MPH hit the down arrow twice quickly without touching the gas pedal. You will see what I mean by harsh.
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I absolutely know what a harsh downshift feels like as my previous SOB with ISX600 called for 2nd gear.
I don’t want my new driver needlessly hunting for the shift pad when he failed to realize the bus had picked up more speed down hill than safe.
I totally agree that a more experienced drive can better control by manually downshifting. A new driver – not so much.
Anyway, I understand what other people’s need are, skill level, and mechanical consequences.
Back to my original question, is the diagnostic port the same for the Allison as the one used for the Detroit ECM? Mark, that seems to be what you are saying. Easy then.
Thanks.
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Les, are you teaching Glen to drive the bus? Geo.
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Geo,
In our neighborhood ( https://gardensrvvillage.com/ ) we are fortunate to have a professional person that has trained thousands of “better halves” to drive RVs.
Glen had driven our previous coach just enough to be able to get it to a safe place in case of an emergency. He is now progressing well in a multi-level formal training course. On our recent trip to Orange Beach, Glen drove twice and did extremely well, passing Rain 101, Rain 201, Construction 101, and Extended Bladder 101.
I see a huge advantage of me NOT being the actual trainer. I had to pass the trainer’s course of how to be a passenger. It was tough and I’m still in therapy.
Happy Trails
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Les, I get it on all levels. LOL Geo.
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Les, Glen is not going to be looking for the shift pad. If he is taught to anticipate hills and control his speeds he will have topped the hill and proceeded down in the correct gear at his target speed. Using the jake or retarder for speed control going down a hill is a procedure to practice and unlike emergency stopping it is something dealt with easily in a routine manner. A quick glance is all it takes to select the correct jake or retarder setting along with hitting a shift pad arrow, up or down. Managing speed just takes practice but if you reprogram the downshift it actually will make it harder for a driver hoping to avoid harsh downshifts.
I hope his trainer emphasizes as a driver he will get a lot of performance from the coach, going up or down hills by manually shifting up and down and using the throttle in concert with the shifts. He needs to fully understand climbing a hill requires manual downshifting, the use of “performance mode” and use of the cruise control to get maximum HP. Then going down the opposite side of the hill uses similar control, but in the reverse way. With practice the use of brakes can be avoided. Going down the hill the thing to avoid is over revving the engine and a transmission programmed to drop multiple gears can do just that.
Also, as a driver gains experience his hand can go to any switch or device without seeking for it.
1999 XLV X-6872, liberty #440 -
Yes Les…everything goes through that port…either the front or rear…makes no difference.
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Thanks Mark.
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