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RVAW
New Member
6 Posts |
 Posted - 03/24/2011 : 08:28:50 AM
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| we have an allison at545 that shifts fast first shift is at 6mph the second at 11mph and the final at 25mph the customer says they want the final shift at 35mph any ideas would be very helpfull |
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78fordwayne
Top Member
USA
2868 Posts |
Posted - 03/24/2011 : 09:06:07 AM
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| Does this bus or truck have a "kick down" cable from the trans to the accelerator or is it electric ? If it has the cable , adjusting the cable will change the shift points. |
Robert B.
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RVAW
New Member
6 Posts |
Posted - 03/24/2011 : 1:15:05 PM
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| it is electronic |
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matts4290
Advanced Member
224 Posts |
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C.HARDY
Advanced Member
354 Posts |
Posted - 03/26/2011 : 10:04:24 AM
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| I've got one that shifts up to 4th then back to 3rd. If you dont floor board it it will keep shifting back and forth until it gets up to 40 or so. |
"Hardybusman" |
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bus724
Top Member
USA
1609 Posts |
Posted - 03/26/2011 : 10:23:52 AM
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quote:
Originally posted by C.HARDY
I've got one that shifts up to 4th then back to 3rd. If you dont floor board it it will keep shifting back and forth until it gets up to 40 or so.
I have a 99 AmTran RE that does the same thing once in a while. I asked an Allison dealer tech once, and he said there's a conversion kit to add the mechanical cable from the throttle that might fix it, but that's not an option for mine since it's rear-engine. I can live with it (camper conversion), but if you find an easy fix please share.  |
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bwest
Administrator
United States
3820 Posts |
Posted - 03/26/2011 : 3:39:05 PM
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You can't put a cable on an electronic engine. You are going to have to put up with the "hunting" as I call it. I try to tell my drivers to drive them like there's stolen.  They seem to shift better like that. Seriously though, if you put the throttle to the floor on take off they will not do that. The main trouble I have with them is when you come up to a stop sign and don't come completly to a stop. When you get back into the throttle they will "hunt". Your suppose to stop anyway so no problem right? |
Bryan |
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bluebirdvision
Top Member
USA
1081 Posts |
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Thomasbus24
Administrator
USA
4559 Posts |
Posted - 03/27/2011 : 05:15:05 AM
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quote:
Originally posted by bwest
You can't put a cable on an electronic engine.
Sure can, I've got two of em. Cat 3126 with MD643 behind em in FS65 chassis. Our trouble was that they were upshifting too soon and lugging the engine so the local Allison dealer added a kit at no cost.
More or less just what you'd find on any mechanical engine bus, except that there is a bracket that attaches to the accelerator pedal assembly that operates the cable. |
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RVAW
New Member
6 Posts |
Posted - 03/28/2011 : 05:53:24 AM
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| a mechanic at the school bus garage said they took the pan off and one solenoid had an adjustment like a rifle scope the turned it down 3 clicks and fixed it |
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bwest
Administrator
United States
3820 Posts |
Posted - 03/28/2011 : 10:33:19 AM
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quote:
Originally posted by Thomasbus24
quote:
Originally posted by bwest
You can't put a cable on an electronic engine.
Sure can, I've got two of em. Cat 3126 with MD643 behind em in FS65 chassis. Our trouble was that they were upshifting too soon and lugging the engine so the local Allison dealer added a kit at no cost.
More or less just what you'd find on any mechanical engine bus, except that there is a bracket that attaches to the accelerator pedal assembly that operates the cable.
Really, I'd be interested in that. Who puts it out, Allison? I really don't have a good Allison dealer around here so I'm in the dark most of the time. The reason I responded with "can't do it" is that I know there is no mechanical linkage from a 3126 or a C7. I stand corrected! |
Bryan |
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slippert
Top Member
USA
630 Posts |
Posted - 03/28/2011 : 11:25:42 AM
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| Sooooo, if there's a cable kit that hooks on to the electric throttle pedal inside cab, where does the other end of cable go on a at545 with electronic modulator? or do the md643's have something different to regulate shift. Just curious |
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Thomasbus24
Administrator
USA
4559 Posts |
Posted - 03/28/2011 : 12:18:43 PM
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bwest, I am not certain if it was an Allison kit or not, but like I said it was an Allison dealer that did it for us back in 99. http://www.wwwilliams.com/locations_trans.cfm The Columbus/Hilliard, Ohio location to be exact. If you need one, I suggest calling them, they know their stuff and should be able to get you on your way.
As for the AT545 vs MT643, it should be the same setup, modulator in the left side, halfway back.
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Edited by - Thomasbus24 on 03/28/2011 12:20:34 PM |
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slippert
Top Member
USA
630 Posts |
Posted - 03/28/2011 : 12:54:24 PM
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| sooo,if it's a electric modulator on the left side halfway back, I'm still curious where that end of cable hooks? or did this kit come with a different modulator with mechanical actuation? |
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Thomasbus24
Administrator
USA
4559 Posts |
Posted - 03/28/2011 : 1:48:04 PM
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| OH, I gotcha!!! The electic modulator is removed and thrown in the trash where it belongs, the cable one replaces it all together. |
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bwest
Administrator
United States
3820 Posts |
Posted - 03/28/2011 : 8:21:06 PM
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quote:
Originally posted by Thomasbus24
bwest, I am not certain if it was an Allison kit or not, but like I said it was an Allison dealer that did it for us back in 99. http://www.wwwilliams.com/locations_trans.cfm The Columbus/Hilliard, Ohio location to be exact. If you need one, I suggest calling them, they know their stuff and should be able to get you on your way.
As for the AT545 vs MT643, it should be the same setup, modulator in the left side, halfway back.
Forgive me for the 20 questions but I am trying to work this out in my mind. When this was done in '99 was it a new bus or was it a year or two old. Because if it was older than a '99 it would have had a 3116 and that would explain a lot. |
Bryan |
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Thomasbus24
Administrator
USA
4559 Posts |
Posted - 03/29/2011 : 12:07:38 PM
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Ask all the questions ya yant!!!
It was done around September or October of 99. We accepted deliver of two FS65 in June of 99, one was a month old. The other was a dealer demo with around 3000 miles on it. It was built 12/97, titled as a 98, and is equipped with a 3126. It has that same electronic pedal that was used up til 2003 or so when they went to that monsterous one.
Perhaps since it was one of the first units and destined to be the only dealer demo in the state at that time, they pushed ahead and put the new engine in it?
Spring break this week, but I'll be in that area Saturday and will get you some pictures. Unless it's on a trip, then it'll be Monday.
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Edited by - Thomasbus24 on 03/29/2011 12:16:25 PM |
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Thomasbus24
Administrator
USA
4559 Posts |
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RVAW
New Member
6 Posts |
Posted - 04/15/2011 : 1:48:12 PM
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| we found that the shift points on our trans are adjusted on the front of the valve body there are threestep adjusters in the front of the valve body just behind a spring roll pin if you turn them in adding more pressure to the spring the shift points go up thanks for the help |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 04/15/2011 : 2:42:39 PM
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quote:
Originally posted by Thomasbus24
http://www.flickr.com/photos/27265743@N03/sets/
Under "Frieghtliner Modulator" set you'll find the buses in question. Man it's a pain to get pictures of that pedal!
That's a nice fix there on the cable modulator. I remember wanting something like that back in 1999 when we first got the Chevrolet BB with the Cat 3126. The damn electronic modulators were not working correctly, some had relays missing, others were CAT ecu signals missing, a couple just flat out were not wired from the factory. The boxes wouldn't communicate with each other, etc. Cat blamed allison, who blamed GM. What did GM say? It's got to be the body builders problem. Guess who had to fix them. :( |
“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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bluebirdvision
Top Member
USA
1081 Posts |
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bwest
Administrator
United States
3820 Posts |
Posted - 04/15/2011 : 8:44:57 PM
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| Soooo.... What does it look like down on the transmission? Is that a whole different pedal? This is interesting! Wonder why I haven't heard of this before? Well, the last one I can answer, I've got a lousy Allison dealer (same as my local IH dealer, arrrgh!!!) |
Bryan |
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Thomasbus24
Administrator
USA
4559 Posts |
Posted - 04/16/2011 : 08:49:25 AM
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There is a picture of what it looks like down under... http://www.flickr.com/photos/27265743@N03/5582637987/in/set-72157626289148399
The entire set of photos... http://www.flickr.com/photos/27265743@N03/sets/72157626289148399/
Just like any older bus with a cable type modulator. That is the same pedal they came from the factory with, Allison just added a bracket to it.
Call up W.W. Williams in Columbus at (800) 336-6651 They are the ones who did it, they should be able to set you up with part numbers at the very least.
I'll have to see if I can get a really good side shot of the entire thing, it's such a pain in the ass to get down in there. |
Edited by - Thomasbus24 on 04/16/2011 08:51:21 AM |
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bwest
Administrator
United States
3820 Posts |
Posted - 04/16/2011 : 2:14:04 PM
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I appologize, I saw that and just thought it was the side of the engine. My bad! So I guess the settings are just like it would be if it was on a 3116 then?
Does it affect the pedal feel? |
Bryan |
Edited by - bwest on 04/16/2011 2:14:40 PM |
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Thomasbus24
Administrator
USA
4559 Posts |
Posted - 04/17/2011 : 05:08:40 AM
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Ya know, I don't really know about the settings now that you mention it. I would assume so, or that Allison has specific specs for a 643/3126 combo.
As for pedal feel, it is a little harder to press than it was before, but not as hard as a 3800 or S series. Haven't had any complaints about difficulty maintaining control at lower speeds (ie pedal being too sensitive) but to be fair, this is a very rural area. |
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allison at545 shifting
