Purchasing transmissions

Jeff Breck

New Member
Joined
May 4, 2025
Posts
3
Location
North Carolina
Hey everyone I just bought a bus and it has a 545 and I'm looking for a mt 643, sae #2 bell housing , torque converter and fly whell. Does anybody know of any used ones available or where we can purchase a reman from?? Thanks in advance for the help
 
I don't know where, I've considered it myself as it's a mechanical option.

It does seem you considered the flywheel and the SAE # so it would seem you've done your research. Last I heard is that there were a majority of them stored in a warehouse somewhere some company bought up and was sitting on them, but I have no reference to where or who that is. Caddilackid who frequented this forum may have had some info on that but he recently seems to have stopped posting. Maybe someone else knows.

Sorry i'm not much more help than that.

A quick search turns up this here:
Transmissions for sale.
 
Hey everyone I just bought a bus and it has a 545 and I'm looking for a mt 643, sae #2 bell housing , torque converter and fly whell. Does anybody know of any used ones available or where we can purchase a reman from?? Thanks in advance for the help
$1925

Then there is sourcing TCM and other associated parts.

have you considered looking for a a donor bus/truck where you can all the parts you need in one place? what engine/chassis are you doing the upgrade on?
 
$1925

Then there is sourcing TCM and other associated parts.

have you considered looking for a a donor bus/truck where you can all the parts you need in one place? what engine/chassis are you doing the upgrade on?
Not sure I need a TCM for this style of transmission. I was under the impression you only needed that for Allison 2000 or an MD 3060. Correct me if I'm wrong
 
Hey everyone I just bought a bus and it has a 545 and I'm looking for a mt 643, sae #2 bell housing , torque converter and fly whell. Does anybody know of any used ones available or where we can purchase a reman from?? Thanks in advance for the help
I just got done doing this swap in a 33' flatnose 95 Blue bird bus with a 5.9 transmission. I started with a AT545 Transmission and went to a MT643 I had on a pallet in the shop. I went to a local junk yard and got all the parts I was missing. (They told me it couldn't be done)
I had to get the bigger bell housing, flexplate, spacer and flywheel. I did this by walking around in the junkyard and measuring every 5.9 bellhousing till I found the right one and then took all the parts off that i was missing.
Other than that, I swapped the yoke from the old to the new, built my own transmission brace to help support the heavier transmission, and swapped all the sensors over. and then shortened the driveshaft at a local truck shop that offered that.

We drove the bus from Pink Hill, NC to Salem OH a few weeks ago. Went through Mt Airy and Wytheville so we could try it out in the mountains.

My goal was to increase speed, mpg, and achieve a lock in torque converter. We accomplished all 3.
New MPG is about 10, it really shifts out of overdrive when you go up the mountains although your speed drops to around 40 mph. and our top speed is about 65 on the flats.

I was very happy with how it turned out and most of the credit goes to the truck shop i did it in. Limestone Creek General Repair out of Beulaville, NC. My cost was about $2,000 for everything and i expect to recoup that because of the fuel savings going from 5 mpg to 10 mpg.
 
Oh, by the way, if anyone needs a 545 i have one i would about give away sitting on a pallet here. 37,000 miles on it. there was nothing wrong with it but i didn't like how that transmission operated for what i wanted to do.
 
I just got done doing this swap in a 33' flatnose 95 Blue bird bus with a 5.9 transmission. I started with a AT545 Transmission and went to a MT643 I had on a pallet in the shop. I went to a local junk yard and got all the parts I was missing. (They told me it couldn't be done)
I had to get the bigger bell housing, flexplate, spacer and flywheel. I did this by walking around in the junkyard and measuring every 5.9 bellhousing till I found the right one and then took all the parts off that i was missing.
Other than that, I swapped the yoke from the old to the new, built my own transmission brace to help support the heavier transmission, and swapped all the sensors over. and then shortened the driveshaft at a local truck shop that offered that.

We drove the bus from Pink Hill, NC to Salem OH a few weeks ago. Went through Mt Airy and Wytheville so we could try it out in the mountains.

My goal was to increase speed, mpg, and achieve a lock in torque converter. We accomplished all 3.
New MPG is about 10, it really shifts out of overdrive when you go up the mountains although your speed drops to around 40 mph. and our top speed is about 65 on the flats.

I was very happy with how it turned out and most of the credit goes to the truck shop i did it in. Limestone Creek General Repair out of Beulaville, NC. My cost was about $2,000 for everything and i expect to recoup that because of the fuel savings going from 5 mpg to 10 mpg.
That's really helpful! Thanks for the input
 
Not sure I need a TCM for this style of transmission. I was under the impression you only needed that for Allison 2000 or an MD 3060. Correct me if I'm wrong
True...my brain fart... it is all mechanical...
 
I did the swap, It was not very straight forward, in heinsight i may not do it again and stay with the 545.

I picked up an MT643 from Eli at Diesel Core with all the needed parts, he currently has one for sale with all the flywheel wheel, bell housing and flexplate.

Issues I ran in to,

1) 643 bell housing was too wide, I had to get it shaved at a prescision metal work place.
2) 643 starter position was on the opposite side. Rewire starter and main buss bar connections.
3) Speed sensor port was open, had a challenge finding a plug for the threaded hole as my speed sensor is / was on the front wheel drum.
4) Dip stick tube position different, had to bend the tube to get it to kind of fit.
5) Piping to existing oil cooler (factory oil / water radiator) was too small for the oil flow from a 643, had to buy and install a derale hi efficiencey cooling rad and fan, all new piping.
6) The trans is 200lbs heaver, it will add extra weight to you 5.9 that it was not designed for, in our situation the extra weight it lifting the front of the engine on its mount and vibrating through the chassis.
7) could not get it in the gap between the front axle and engine, had to tip it up on its end to get it up and over the front axle,
8) needed to shorten the drive shaft by 1.25" as 643 is a little longer

Although I do have locking now in 3rd and 4th, no real gain in MPG, no change on top speed as the 643 has NO overdrive so 4th is still 1:1, same as the 545
 
Yeah if I'm going to to into that much work I'd rather put that work into an AT1000 or MD3060.
 
I had to do a lot of the same work and you probably are right that for all of this why not go with a different transmission.
I did not have to shave anything down to fit and as I said, we added a crossmember to support the extra weight of the heavier transmission.

I hope to drive my bus down to Guatemala and back and didn't want any computers. There are plenty of parts for 12 valve cummins engines available in Central America and I figured a transmission without any electronics would be a safer bet.

I'm happy with my swap but it may not be for everyone.
 
I had to do a lot of the same work and you probably are right that for all of this why not go with a different transmission.
I did not have to shave anything down to fit and as I said, we added a crossmember to support the extra weight of the heavier transmission.

I hope to drive my bus down to Guatemala and back and didn't want any computers. There are plenty of parts for 12 valve cummins engines available in Central America and I figured a transmission without any electronics would be a safer bet.

I'm happy with my swap but it may not be for everyone.
WOW, When you driving to Guate ???

I did several trips back in the '80's to Honduras...the wife and I were dreaming about doing another trip but going solo is out of the question for me.

Back when we did the trips we always formed a caravana with others going to either Guate or Honduras for safety...

sorry, not trying to hijack the thread...
 
Short answer: We don't know when we are going. We hope to leave the end of the month if we can get a title by then. We have never driven in a caravan but I have family who does that when taking vehicles down to sell.

Long answer: Maybe someone who reads this will know how to fix something like this.

We bought the bus from someone who had titled the bus in Vermont as an RV but lived in another state. Vermont allowed that for a while but apparently they didn't give you an actual title if the vehicle was older than 2004. They gave you this cool registration that had places to sign ownership over to someone else when you sold it just like the titles we use in NC.
However, in 2024 Vermont discontinued allowing people who don't live there to register their vehicles as motorhomes in VT. So that won't work for me.

But the NC DMV refused to accept that signed registration as a valid title transfer.

I called Vermont and asked them for a title and was told that I cannot request one since i am not the registered owner. Yes, they said, the registered owners had turned in the registration showing they sold me the vehicle, but they would have to request a title and mail it to me if I needed one.

The previous owners were very kind and paid the $42 to request a title be sent to them and VT says they mailed them a title in March, but the owners say they never received the title.

I finally applied for a bonded title here in NC and have the tags and plates in my name but i do not have a physical title in my hand until some mysterious person in the special title division sends me one in the mail? I can drive the Skoolie anywhere in the US but I am pretty sure I need the title with me to cross the borders to go through Mexico and Belize. I had to last time we went...

So, if anyone knows how to get a title quickly from Vermont who doesn't live there, or if you know how to talk to the mysterious person in the NC DMV who makes out the bonded title divisions... I'd appreciate help.

Long answer is that we plan to drive down this summer if the title comes in time to be back before school starts in the fall.
 
Short answer: We don't know when we are going. We hope to leave the end of the month if we can get a title by then. We have never driven in a caravan but I have family who does that when taking vehicles down to sell.

Long answer: Maybe someone who reads this will know how to fix something like this.

We bought the bus from someone who had titled the bus in Vermont as an RV but lived in another state. Vermont allowed that for a while but apparently they didn't give you an actual title if the vehicle was older than 2004. They gave you this cool registration that had places to sign ownership over to someone else when you sold it just like the titles we use in NC.
However, in 2024 Vermont discontinued allowing people who don't live there to register their vehicles as motorhomes in VT. So that won't work for me.

But the NC DMV refused to accept that signed registration as a valid title transfer.

I called Vermont and asked them for a title and was told that I cannot request one since i am not the registered owner. Yes, they said, the registered owners had turned in the registration showing they sold me the vehicle, but they would have to request a title and mail it to me if I needed one.

The previous owners were very kind and paid the $42 to request a title be sent to them and VT says they mailed them a title in March, but the owners say they never received the title.

I finally applied for a bonded title here in NC and have the tags and plates in my name but i do not have a physical title in my hand until some mysterious person in the special title division sends me one in the mail? I can drive the Skoolie anywhere in the US but I am pretty sure I need the title with me to cross the borders to go through Mexico and Belize. I had to last time we went...

So, if anyone knows how to get a title quickly from Vermont who doesn't live there, or if you know how to talk to the mysterious person in the NC DMV who makes out the bonded title divisions... I'd appreciate help.

Long answer is that we plan to drive down this summer if the title comes in time to be back before school starts in the fall.

Real simple, this time you pay the fee, have the seller get another title (lost in mail) but this time have it sent to your address.
 
Actually I called Vermont and they said the title must be lost in the mail, so with the permission of the registered owner they mailed me a title directly.
WOW! I should have thought to ask the lady who helped me if she was an angel, because if she was i wonder what she would have said.
and if she was just someone doing her job it would have made her day.
but I am very grateful for having a title in the mail coming to me.
 
Doesn't it feel really good that when something that we overthink gets easily fixed by a simple phone call!

Congrats!
 

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