Bought my First school bus and it broke down half way home

[Gambler936]

Originally Posted by cadillackid

you can still buy a reman MT643 for about $650.. LKQ in missouri still has a few.. i know of someone who just got one.. im a year-in now with the 643 swap on my DEV bus.. one of the best things i ever did (other than add A/C) to that bus..

-Christopher

How much was the swap in labor?

[EastCoastCB]

Originally Posted by Gambler936

How much was the swap in labor?

He did it himself.

[ralats]

i have never saw a 640 series allison reman for 650.00 lkq is a used parts yard and the trans is much larger than the 500 it has more foward speeds and doesnt just swap out you will have issues with the park brake cable 500 is to short the driveshaft has to be shortened

[EastCoastCB]

Originally Posted by ralats

i have never saw a 640 series allison reman for 650.00 lkq is a used parts yard and the trans is much larger than the 500 it has more foward speeds and doesnt just swap out you will have issues with the park brake cable 500 is to short the driveshaft has to be shortened

LKQ has 643's reman for $650. A 643 has the same amount of forward gears as a 545.

[ralats]

you are wrong 540 allison is a 5 speed transmission mt643 is a 6 foward speed transmission two different units two different units no internal parts are he same

[EastCoastCB]

Originally Posted by ralats

you are wrong 540 allison is a 5 speed transmission mt643 is a 6 foward speed transmission two different units two different units no internal parts are he same

LOL no man you're just dead wrong. The 2nd number in the allison transmission of that era indicates the # of forward gears. 545 and 643 most certainly are both 4 speed transmissions with 1:1 4th gear. Prove me wrong.

I've literally had multiple buses with these transmissions.

[ralats]

look it up you have no idea what your talking about check lkq 545 allison is 2000.00 643 allison 2700.00 with good core dont care how many buses you owned i have been rebuilding them for 40 years

[cadillackid]

Originally Posted by ralats

you are wrong 540 allison is a 5 speed transmission mt643 is a 6 foward speed transmission two different units two different units no internal parts are he same

the AT540 was an 'Auto truck' transmission in the 500 series with 4 forward gears (the second digit in the old allison numbers was the forward speeds).. an MT640 (643) was a Medium Truck transmission in the 600 series with 4 forward gears (2nd digit)..



an MT653 was a 5 speed (4 plus a granny gear) similar to the MT643..


an HT740 was a 4 speed in the Heavy truck 7 series.. (4 forward gears)..
there was an HT750 series also which was 5 forward gears (1st was a granny gear)


the 500 series had an SAE3 bell (big)

the 600 series had an SAE2 bell (bigger)

the 700 series had an SAE1 bell (Huge)


I bought my remanufactured MT643 from LKQ parts in marshfield missouri for $650.. I drove out and got it myself and installed it in my carpenter bus. . and ive driven 1000s of miles on it.. it has 4 (FOUR) forward gears.. theres a thread on my hopping in my didge pickup and going to get it..



they stil have some it appears....



https://lkqheavytruck.com/part-detai...ON&model=MT643






it replaced an AT545 which I blew up that had 4 (FOUR) forward gears. I drove 1000s of miles on that one..



allison manufacturers several 6 speed units as of today which are modern electronic units in the 1000,2000,3000 range.. the 3000 world series started in the mid 90s.. the 1000/2000 units used in everything from GMC diesel pickups to school busses came out in 2000...

I believe they stil make a 7 speed 4000 but im not sure..



a 9 speed was rumored for 2020 as a GMC transmission with allison's name on it..





thats pretty much the allison scoop as I know it..

[cadillackid]

Originally Posted by ralats

look it up you have no idea what your talking about check lkq 545 allison is 2000.00 643 allison 2700.00 with good core dont care how many buses you owned i have been rebuilding them for 40 years

and here the yare for $645.00 these were in the ReNewed program by Navistar.. they are diesel 2600 RPM units and were obsoleted by navistar in 2018 (15 years after allison discontinued it)..


https://lkqheavytruck.com/part-detai...ON&model=MT643

[cadillackid]

Originally Posted by ralats

i have never saw a 640 series allison reman for 650.00 lkq is a used parts yard and the trans is much larger than the 500 it has more foward speeds and doesnt just swap out you will have issues with the park brake cable 500 is to short the driveshaft has to be shortened

yeppers I had to shorten the driveshaft, use a different flex plate, reworked my trans lines. . I have air brakes so no park brake issues on mine.. had to lengthen speed sensor wire.



the little bugger was a tad on the heavy side but thats why I have a garage full of tools and stands and hoist and jacks and such

[EastCoastCB]

Originally Posted by ralats

look it up you have no idea what your talking about check lkq 545 allison is 2000.00 643 allison 2700.00 with good core dont care how many buses you owned i have been rebuilding them for 40 years

you're obviously having a laugh or on something real strong, bud.
Or your google is TERRIBLY broken.

[cadillackid]

Originally Posted by EastCoastCB

you're obviously having a laugh or on something real strong, bud.
Or your google is TERRIBLY broken.

LOL I had google tell me once that AT545 stood for Automatic-Transmission 5 speed and MT643 was Manual-transmission 6 gears so im guessing he found a similar page? i couldnt find the one anymore.. ha!

[johnbloem1974]

Wow!! Just to add to the confirmations... I had an At545...4 forward gears. I blew it up, replaced it with an MT643...4 forward gears with a lockup torque converter. Best decision ever made!!

Cheers, guys!

John

[QualityBusGuy]

i just saw your conversation and thought you might be interested in a school bus recycler out of MN. I know they part out old school buses and sell parts fairly reasonable. It looks like they have plenty of AT545s and a couple MT643s

https://qualitybusandtruckparts.com/parts/

[Gambler936]

Originally Posted by johnbloem1974

Wow!! Just to add to the confirmations... I had an At545...4 forward gears. I blew it up, replaced it with an MT643...4 forward gears with a lockup torque converter. Best decision ever made!!

Cheers, guys!

John

Did you do the swap your self? Or have a shop do it and if a shop did it how much did they charge you?

[Gambler936]

Hey everybody just an update the Tranny and torque converter is bad, he’s going to call me Monday to give me a quote on a rebuild (which I’m not doing) and a swap to the 643( which I want to do) I’ll let you all know how it goes thanks for all the info and support

[EastCoastCB]

Originally Posted by cadillackid

and here the yare for $645.00 these were in the ReNewed program by Navistar.. they are diesel 2600 RPM units and were obsoleted by navistar in 2018 (15 years after allison discontinued it)..


https://lkqheavytruck.com/part-detai...ON&model=MT643

Buy one of these, OP ^^^

[Gambler936]

Originally Posted by EastCoastCB

Buy one of these, OP ^^^

Does it come with a torque converter or do I need to get one as well

[WIbluebird]

Why did International ever think it was a good idea to sell DT466/AT545 buses? Why buy a bus that has been intentionally detuned just so it can barely coexist with that boat anchor of a transmission?

[EastCoastCB]

Originally Posted by WIbluebird

Why did International ever think it was a good idea to sell DT466/AT545 buses? Why buy a bus that has been intentionally detuned just so it can barely coexist with that boat anchor of a transmission?

Penny pinching school districts.