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12-31-2015, 01:43 PM
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#1
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Bus Crazy
Join Date: Apr 2013
Location: Colorado
Posts: 2,362
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
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transmission wisdom
ok fellow skoolies, i'm looking for some future advice.
i predict that my transmission will fail (at 545). it makes noise, it slips on grades, it makes me worry
plus i like to tow with it
it is paired to cummins 5.9 12v in a flat front FE bluebird.
so, if the trans fails..... do i rebuild it?
do i find a donor bus and swap the 545?
do i find a donor bus with a md3060?
do i find a donor bus with a FE 8.3 cummmins and transmission combo? would that fit?
are there other options?
might be easier to move the conversion onto a new bus instead of a repower.
whats the cheapest/best fix on something this major?
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12-31-2015, 01:51 PM
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#2
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Moderator
Join Date: Feb 2007
Location: NUNYA
Posts: 4,236
Year: 1995
Coachwork: Thomas
Chassis: 3800
Engine: DT408, AT545
Rated Cap: 23 500 gvw
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You can buy a rebuilt AT545 for about $1800. That is the simplest option. I have also seen used 545s on craigslist for as cheap as a few hundred. Someone here had one here that the offered for free.
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12-31-2015, 02:13 PM
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#3
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Bus Crazy
Join Date: Apr 2014
Location: EHT New Jersey
Posts: 1,134
Year: 2003
Coachwork: AmTran
Chassis: International 3000RE
Engine: T444E/AT545
Rated Cap: 75
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Swap it with an MD3060
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12-31-2015, 03:01 PM
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#4
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Bus Crazy
Join Date: May 2010
Location: Montana
Posts: 1,626
Year: 1995
Coachwork: Blue Bird
Chassis: All-American R/E
Engine: 8.3 Cummins
Rated Cap: 72
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Tango had one he was giving away.
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12-31-2015, 04:00 PM
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#5
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Bus Nut
Join Date: Jan 2015
Location: Gonvick MN
Posts: 339
Year: 1975
Chassis: Gillig
Engine: Cat 3208t/10 speed transmission
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I have an 545.
Free for bus people.
__________________
Remove hence to yonder place....
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12-31-2015, 05:15 PM
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#6
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Bus Geek
Join Date: Mar 2011
Location: Houston, Texas
Posts: 8,462
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
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Me too. Free to any Skoolie who needs it. In Houston Texas.
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12-31-2015, 06:17 PM
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#7
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Moderator
Join Date: Feb 2007
Location: NUNYA
Posts: 4,236
Year: 1995
Coachwork: Thomas
Chassis: 3800
Engine: DT408, AT545
Rated Cap: 23 500 gvw
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A swap is fine but not a simple task if you don't have the skills. The MD3060 requires a computer. The shifter alone is 500-1000, so is the ECU. If money is no object, go for it.
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12-31-2015, 06:25 PM
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#8
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Bus Geek
Join Date: Mar 2011
Location: Houston, Texas
Posts: 8,462
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
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And if you have ten-grand...the new gen Allison six speeds have double OD and don't need a computer. Just a TPS (Throttle Position Sensor).
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12-31-2015, 07:17 PM
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#9
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Moderator
Join Date: Feb 2007
Location: NUNYA
Posts: 4,236
Year: 1995
Coachwork: Thomas
Chassis: 3800
Engine: DT408, AT545
Rated Cap: 23 500 gvw
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Quote:
Originally Posted by Tango
And if you have ten-grand...the new gen Allison six speeds have double OD and don't need a computer. Just a TPS (Throttle Position Sensor).
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Sure, I'll take 2 please.
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01-01-2016, 09:34 AM
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#10
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Bus Crazy
Join Date: Apr 2013
Location: Colorado
Posts: 2,362
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
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2 ?!?!?! good grief
didnt i ask for cheapest / best?
at 10k, i think, i could transplant the bigger cummins plus trans.
i think the simplest answer is probably the cheapest..... swaping a used 545 in.
therefore, im interested in either of those 545's. googling your locations im half way in between both of you.....from colorado its a 1000 miles either way.
does the fact that one came from a cat motor change the bell? any ideas on the mileage on those trans?
thanks for all the help!!!
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01-01-2016, 10:57 AM
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#11
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Bus Geek
Join Date: Mar 2011
Location: Houston, Texas
Posts: 8,462
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
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Mine is an SAE 3 that was bolted directly to a Cummins 4BT. Same pattern as a 6BT. I never ran it but was told prior to purchase it was fully functional as was the engine I bought with it. It also has a driveline park brake attached.
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01-01-2016, 03:10 PM
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#12
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Bus Crazy
Join Date: Apr 2013
Location: Colorado
Posts: 2,362
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
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dangit! looks like im going to houston
my bus has 300k miles on it...... the engine seems strong, but that trans gives me night mares.
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01-01-2016, 03:19 PM
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#13
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Moderator
Join Date: Feb 2007
Location: NUNYA
Posts: 4,236
Year: 1995
Coachwork: Thomas
Chassis: 3800
Engine: DT408, AT545
Rated Cap: 23 500 gvw
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You want to try for a trans that was behind a similar engine if not the same. They have shift patterns tailored to engine rpms.
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01-01-2016, 03:24 PM
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#14
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Bus Crazy
Join Date: Apr 2013
Location: Colorado
Posts: 2,362
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
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hmmm, ..... edjumacate me
this is over my pay grade
thanks for all the kind replies!!
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01-01-2016, 05:47 PM
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#15
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Bus Nut
Join Date: Sep 2013
Location: Denver
Posts: 489
Year: 1982
Coachwork: Blue Bird
Chassis: International S1800
Engine: DT466 Trans: MT643
Rated Cap: 65
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There are some 5.9s with MT643s behind them. That would be an upgrade
__________________
Patina enthusiast and professional busman
www.bustoshow.org
Blog: www.lookatthatbus.com
Instragram: @lookatthatbus
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01-01-2016, 08:41 PM
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#16
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Moderator
Join Date: Feb 2007
Location: NUNYA
Posts: 4,236
Year: 1995
Coachwork: Thomas
Chassis: 3800
Engine: DT408, AT545
Rated Cap: 23 500 gvw
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Quote:
Originally Posted by turf
hmmm, ..... edjumacate me
this is over my pay grade
thanks for all the kind replies!!
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Different engines have different power bands. Here is a definition that
probably explains it better than I can. An AT545 from behind a 4 cylinder diesel probably shifts at a higher rpm than a 6 cylinder. An Allison shop can probably make adjustments. I don't know if I can do better than that. Anyone else want to chime in?
https://en.wikipedia.org/wiki/Power_band
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01-01-2016, 09:53 PM
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#17
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Bus Crazy
Join Date: May 2010
Location: Montana
Posts: 1,626
Year: 1995
Coachwork: Blue Bird
Chassis: All-American R/E
Engine: 8.3 Cummins
Rated Cap: 72
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I've read using a C-3 oil in them gives them better performance. C-3 hydraulic oil or 5W20 or 5W30 engine oil, which is C-3 rated as well.
They're pretty bombproof trannys. But you need to like to coast to a stop with them.
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01-01-2016, 11:47 PM
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#18
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Bus Crazy
Join Date: Jul 2011
Location: Winlcok, WA
Posts: 2,233
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If you have an AT540 series transmission it would be best to replace it with a like transmission.
If you shop around you should be able to get one installed for less than $3.5K. Good rebuilts that are built for your specific engine and application are available for under $2K.
A transmission that was behind a 5.9 is not going to have the same valving and governors as a transmission that was behind a 7.3.
While a good Allison tech might be able to swap stuff out to make it work it is a lot easier and cost effective to get what you need at the beginning.
Swapping up to an MT640 series would be a big step up but the costs would be considerably higher since you wouldn't have a core to swap so you would be purchasing the transmission outright.
The same would hold with going to any of the newer WT series transmissions.
Personally I don't understand the angst about the AT540 series transmissions. I agree they don't hold back going down hills and not having a lock up makes them a little less fuel efficient. But at the same time I have seen them go well over 200K miles in 11-12 row conventional or TC2000 buses.
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01-02-2016, 08:46 AM
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#19
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Bus Crazy
Join Date: Oct 2015
Location: Spring Valley AZ
Posts: 1,343
Year: 2000
Coachwork: Bluebird
Engine: 5.9 Cummins
Rated Cap: 2 elderly children, 1 cat
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AT54_s are TH400s on steroids. Open one up and there's a TH looking at you (almost).
There are 100s of thousands, of ATs running around in trash trucks, skoolies and every large rental truck I've used. Basic, sturdy power delivery.
I used to run a long bobtail from Sun Valley CA to Vegas with one behind a DT466 many times. Most of our line trucks at (now) AT&T had them. (I retired in '94 so don't know what they have now)
I mine will downshift from 4th at 55, 3rd at 32 and 2nd at about 24. Not a lot of engine braking but enough that I utilize it often.
The best...perhaps not but they work hard.
YMMV....... Mine does
__________________
Don, Mary and Spooky the cat.
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01-02-2016, 08:08 PM
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#20
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Bus Crazy
Join Date: Apr 2013
Location: Colorado
Posts: 2,362
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
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i agree, your mileage may vary.
this AT545 has 310,000 miles on the clock, slips, overheats, makes noises you never want to hear, has the fragrance of burnt oil, but has kept on going.
after all the inputs..... i dont think i'd have a problem with a rebuilt 545. i think thats smart money.
however, fixing it doesnt address any of the shortcomings of the setup.
if money were no object, i'd go for the mt643, plus a new ring gear in the differential.
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