Reply
 
Thread Tools Display Modes
 
Old 10-19-2018, 12:00 PM   #1
Mini-Skoolie
 
Join Date: Sep 2018
Location: Saint Augusine, FL
Posts: 16
Year: 1990
Chassis: International
Engine: DT360
Swapping a AT545 for a MT643 behind a DT360

Been looking at possible transmission upgrades for my 1990 Blue bird. It has the DT360 and AT545. When I purchased the bus I had about a 40 mile trip on the highway home. The bus would do 65 but really high rpm, managed 60mph easily though. Would swapping in the MT643 net me any MPH and would it bolt up? Found a MT463 about 3hours from me. The person I would be buying it from has a DT466E bolted to it. Said I can have the bell housing adapter, fly wheel, flex plate and TQ converter.
JBK_27 is offline   Reply With Quote
Old 10-19-2018, 12:16 PM   #2
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 21,516
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
Quote:
Originally Posted by JBK_27 View Post
Been looking at possible transmission upgrades for my 1990 Blue bird. It has the DT360 and AT545. When I purchased the bus I had about a 40 mile trip on the highway home. The bus would do 65 but really high rpm, managed 60mph easily though. Would swapping in the MT643 net me any MPH and would it bolt up? Found a MT463 about 3hours from me. The person I would be buying it from has a DT466E bolted to it. Said I can have the bell housing adapter, fly wheel, flex plate and TQ converter.
The 643 won't get you any more speed. It will give you more efficiency and less heat in the cooling system. Its a GREAT upgrade.
But you'll need highway gearing in the rear end to bring the cruising rpm's down. What's your rear axle ratio?
__________________
.
Roll Your Own Build Thread
EastCoastCB is offline   Reply With Quote
Old 10-19-2018, 12:30 PM   #3
Mini-Skoolie
 
Join Date: Sep 2018
Location: Saint Augusine, FL
Posts: 16
Year: 1990
Chassis: International
Engine: DT360
Not sure on the axle ratio, will there be a tag on it??? I can pick up the MT643 for $300.
JBK_27 is offline   Reply With Quote
Old 10-19-2018, 12:34 PM   #4
Bus Geek
 
brokedown's Avatar
 
Join Date: Dec 2016
Location: Weeki Wachee, FL
Posts: 3,019
Year: 1997
Coachwork: Bluebird
Chassis: TC2000 FE
Engine: Cummins 5.9
Rated Cap: 72
Swapping to a mt643 will actually slightly improve your highway cruising speed. The ratios are the same, but you'll be eliminating the slip. But this is more of a technicality, the real advantage is that you'll be putting more of your power to the road instead of turning it into heat.

There might be a tag on the axle. My cluebird lists the ratio on a tag above the windshield, my thomas doesn't. You may also be able to find it by running your vin/body number on bluebird's vantage site.
__________________
Keep up with us and our build!
Follow us on Facebook, Instagram, YouTube, and Twitter
brokedown is offline   Reply With Quote
Old 10-19-2018, 01:11 PM   #5
Mini-Skoolie
 
Join Date: Sep 2018
Location: Saint Augusine, FL
Posts: 16
Year: 1990
Chassis: International
Engine: DT360
I'm really curious if the stall will be correct for my 360 being that the trans is coming off of a 466E.
JBK_27 is offline   Reply With Quote
Old 10-19-2018, 01:56 PM   #6
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 1,603
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
ive had 2 different torque converters in my bus. iirc, i went from as 1300 to a 1900 stall speed.

they both worked fine. the new one, the 1900, launches me faster. which i like.

i have a 5.9 that had an AT545 and swapped into an AT1545.

ymmv
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 10-19-2018, 02:00 PM   #7
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 6,318
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
Quote:
Originally Posted by turf View Post
ive had 2 different torque converters in my bus. iirc, i went from as 1300 to a 1900 stall speed.

they both worked fine. the new one, the 1900, launches me faster. which i like.

i have a 5.9 that had an AT545 and swapped into an AT1545.

ymmv
Is the AT-1545 a direct swap for the AT-545? If so, I would think that would be a good upgrade path for 545 owners.
PNW_Steve is offline   Reply With Quote
Old 10-19-2018, 02:02 PM   #8
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 21,516
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
Quote:
Originally Posted by PNW_Steve View Post
Is the AT-1545 a direct swap for the AT-545? If so, I would think that would be a good upgrade path for 545 owners.
I don't if its direct. Turf is REALLY good at working on stuff and IIRC it took him quite a bit of effort.

CaddilacKid will know ALL about what you need to swap a 643 for a 545 behind a DT360. He JUST did this swap on his bus.
$300 for the whole kit and kaboodle is a good deal, IMO.
__________________
.
Roll Your Own Build Thread
EastCoastCB is offline   Reply With Quote
Old 10-19-2018, 04:12 PM   #9
Bus Crazy
 
turf's Avatar
 
Join Date: Apr 2013
Location: Colorado
Posts: 1,603
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison AT1545
Rated Cap: 2
EC is right, it is not a direct swap.

no one knew until its too late.
the lockup makes the TC sticks out about an inch further than the non locking 545.

pretty sure any swap is going to take some custom parts. i don't know the details of 643 swap. but find a 643 that was behind the same engine you have now. that will make sure you have all the parts you need.

the AT1545 was only mated to a cat motor with a much larger flywheel. i ended up making my own spacer to match the distance between the cummins flywheel and the TC.
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 10-19-2018, 04:33 PM   #10
Mini-Skoolie
 
Join Date: Sep 2018
Location: Saint Augusine, FL
Posts: 16
Year: 1990
Chassis: International
Engine: DT360
If the deal holds I’m going to go pick it up next weekend. Like I said he has the bell housing and everything. That bell housing should bolt to my 360 with no modification.
JBK_27 is offline   Reply With Quote
Old 11-02-2018, 06:54 AM   #11
Mini-Skoolie
 
Join Date: Jul 2016
Location: Michigan
Posts: 32
Year: 1999
Coachwork: Bluebird
Chassis: 3800
Engine: DT466E
Rated Cap: 42
I have a 545 behind a 466 in a 1999 Bluebird. It would only do 60 mph because the speed governor in the computer was set at 60 mph. I had it changed by a tech with a laptop and now it goes 75 mph at about 2500-2600 rpm, which is not too fast for the inline IH engines. My fuel mileage is about 7.5 mpg on the long trips at 70 mph, but I can only get about 8 mpg at 60 mph, so I feel it is a good speed for fuel tradeoff. I do have to watch the trans temp on long uphill stretches, but I think a trans cooler would let me keep the hammer down all day.
siloguy is offline   Reply With Quote
Old 11-02-2018, 08:54 AM   #12
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 12,848
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
i just did a DTA360 AT545 to MT-643 conversion.



the 643 comes as an SAE2 bell.. its not swappable. your AT545 is an SAE3.. heres what you need to do..



1. secure a flexplate.. you'll need a new one. the AT545 and MT643 have a different offset and bolt pattern. the part number i used is. navistar 46703C1. thats an 8 bolt flexplate for mechanical dt-466 and all DT-360 engines.. the later DT466E flexplate wont work it is 12 bolt.



2. take out your old 545.. (you access the converter bolts from an access hole in the FRONT of your flywheel housing just above the starter. I used an extension and socket and reached that acess hole from inside the bus with the doghouse off) . from the 545 remove your speed sensor (tailshaft).. neutral safety switch(near shift linkage), reverse light pressure sensor (other side of trans)..and Rear Yoke. you will re-use these on the 643.



3. remove the inner ring on your flywheel housing.. this ring converts the factory SAE2 to SAE3 so that the AT545 would fit. removing this ring gives you the SAE2 mount pattern that the MT-643 utilizes.



4. unbolt the existing flexplate, remove the outer washer ring (save this!), existing flexplate, and 2 inch spacer. its also a good idea to go ahead, pull out the flywheel (its about 25-30 pounds).. and inspect your rear main engine seal.. if its dry then no issues.. if its oily.. change it while things are apart.. also clean any metal shavings off of the Tach RPM sensor that you'll see sticking into the flywheel housing.



5. obtain shorter bolts for the flywheel.. (I used grade 8 2 1/2" but measure yours to be sure.. you want as much thread engagement as you can get without bottom out in the holes)..



6. set your flywheel on the hiub and rotate for all holes to line up. (it will only fit one way.. make sure its not inside out).. then place your new flexplate directly on the flywheel.. (pay attention its marked, trans side and engine side.. dont flip it).. (dont use the thick spacer you removed).. after the flex plate.. install the washer ring.. then bolt it down.. I put a dab of Blue loctite on the threads of each bolt. and then you tighten to 110-115 ft lbs.. (I lodged a wrench in the flywheel so the engine couldnt spin).



7. install the parts you removed from your 545 to your 643.. yoke, and sensors..



8. install your 643 on the bell housing.. its heavy.. be sure to use loctite on your torque converter nuts.. I used blue.



9. test fit and measure in your front driveshaft.. I installed the U-clamps on the front yoke and use a trans jack to jack the shaft up to the correct height.. then madse sure the carrier bearing rubber was center-seated against the bearing.. I measured center line from bracket on bus to carrier bearing bolt holes.. this is the amount you need to shorten the front driveshaft.. I took both shafts to a shop and had the front one shortned.. new U-joints and carrier bearing all around and balanced together as a set. in my case i had to remove 2 1/2" inches.. but measure your own!.


10. plug in your connectors for the switches.. i had to make a 1 foot extension so my speed sensor would reach the harness.. its just a male-female weather-pak connector 2 pin.. you can buy the connectors and make this.



11. install your shift modulator, and dipstick.. Noted on mine.. the dipstick was previously in the middle of the pan height wise and on the 643 its at the bottom. (my 545 was a deep pan like the 643).. I determined id always fill the fluid 1 inch higher on the stick than the marks show.



12. you may need to drill new holes in your shift bracket to get the correct geometry on the cable.. i did...



13. cooler lines.. the cooler line fittings on the 643 are #12 O-ring-Boss.. the lines you disconnected from your 545 are 7/8 flare.. I used some 90 degree #12 ORB to 7/8x14 flare fittings to adapt my lines.. one of my lines was in bad shape, i replaced it using AN fittings and braided steel high pressure line.



14. fill it up with fluid (5 gallons or so) and drive.. i put in 3 gallons.. started the engine... checked it.. added a gallon.. checked it for cold-fill.. i sporung a leak first time out so I pout a couple quarts on the ground.. I ended up just a bit over 5 gallons..



thats a nuitshell of how to do it.. im sure i forgot a detail here or there..



enjoy having lockup - you'll feel like you got a new bus!
-Christopher
cadillackid is offline   Reply With Quote
Old 11-20-2018, 08:35 AM   #13
Skoolie
 
OrionsComfortBus's Avatar
 
Join Date: Jul 2018
Location: Poteet, Tx
Posts: 134
Year: 1993
Coachwork: International - AmTran
Chassis: 3800
Engine: DTA 360
Rated Cap: 25,500 lbs
^THAT^ Should be Pinned or made a Sticky or something. A condensed write-up of the AT545 to MT643 swap.
Very Nice. Thank You Christopher.
__________________
The price of freedom is eternal vigilance. - Thomas Jefferson
Ongoing project of maintenance and replacement of things in and on the Comfort Bus https://www.skoolie.net/forums/f9/up...bus-24772.html
OrionsComfortBus is offline   Reply With Quote
Old 11-20-2018, 08:59 AM   #14
Bus Geek
 
Tango's Avatar
 
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
Brilliant write up! Thanks for sharing. And yes...we need a Tech Library where info like this can be housed forever!
Tango is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 01:48 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×