MT 643 arived today

[Skalbus]

My MT 643 arrived today.
Now it's time to start collecting any other parts I need to do the swap.

Any advise on sourcing parts will be greatly appreciated.

 

[bluebird90]

Please give more info on the bus, engine, what parts you need. We can't help unless you fill us in.

 

[Skalbus]

Please give more info on the bus, engine, what parts you need. We can't help unless you fill us in.

No problem. It's the one in the user box to the left.
95 Genesis Amtram with the DT466.

From what I've been reading I may only need to source a flex plate and bolts.
Any tips on figuring out what flex plate???

 

[bluebird90]

Are you going from manual to auto or at545 to mt643. Because there are different things you will need.

 

[Skalbus]

Are you going from manual to auto or at545 to mt643. Because there are different things you will need.

I suppose that would help.
at545 to mt643

 

[Drew Bru]

check out this thread http://www.skoolie.net/forums/f37/crapped-out-20640.html

it may be of some help. page 3 is where the 643 swap comes into play

 

[bluebird90]

O K, here goes.
The trans must be matched to the application. The guts are the same but the valve body and governor is not. Install the trans with the wrong valve body and you will get early or late upshifts, over revving or bogging. If this trans came from a bus with the same engine and size bus with the same axle ratio, you are golden. otherwise send the valve body to allison for reconfiguring.

Flywheel, same.
flexplate maybe same.
shift linkages, same
modulator, same
drive shaft, different, uses different U joints and length.
Oil cooler lines on the 643 are bigger. using the 545 lines may cause running hot and restricted flow to the converter. Some 643s used the smaller lines tho. check for fit.
The cooler in the radiator may be smaller too on the 545.
You will not be using the adapter ring on the flywheel housing, unless yours is a #3. then you need the whole housing, flywheel , etc..

 

[bluebird90]

The same place you got the trans should have everything else. otherwise any medium truck wreckers should have them.

 

[cadillackid]

these LKQ transmissions are designed for DT's they are 2600 RPM 643's with the proper converter, they were ReMan for Navistar who dropped them off of their official parts list..



you'll need a flexplate for a mechanical DT, if your 545 was a deep pan then your dipstick and trans tempo sensor are same, modulator same, shift cable same.. hydraulic brakes *MAY* require some mods to the park brake drum bracket.. you will need to shorten the front driveshaft. you'll need new flywheel to engine bolts as you'll yank the spacer out... you'll remove the 2->3 ring off the flywheel housing.



things are different if you have a 466E .. what I described is for a mechanical 466 / 360


-Christopher

 

[Skalbus]

Yes, Christopher is correct. The trans is from LKQ and came off of a DT466 mechanical which is what it's going back onto.
Bluebird90, sounds like I just need to get the 545 off and do some comparing of parts. If I'm lucky like the guy in that thread Dru Bru posted it will bolt right up.
With just a quick look it's hard to tell what spacer is on the housing. Looks like about .5". It's dirty so not sure.
The pan is the same depth so I should be good to go there.
Lot's of drive line shops within 80 miles of me so that should work out ok as well.
I wonder, will I need to source a tail shaft for the MT643?
I should be able to make up the fluid lines myself also.
I really appreciate everyone's feedback and guidance to helpful threads. I hope to have it ready to go to Quartzite next year.

 

[cadillackid]

the yoke should bolt up.. do you have a drum on the back of your 545 or are you air-braked?



im doing the same swap on my DTA360 mechanical..


go in from the top to get the converter nuts off... much easier than pulling the starter.. your 643 will be MUCH heavier than the 545.. be prepared for that. the DT doesnt require a secondary mount, however care needs to be taken when getting it intoi position.. when I swap a trans I have 4 bolts that have the heads cut off and are about 2 inches out.. I can line screw those bolts into the flywheel housing.. and then the trans can "ride" those into position.. I dont put as lot of weight on those bolts, however they are good slide-guides.. then I use a ratchet strap to the front frame member of the bus.. I do a lot of crawling and pushing that last little bit but ultimately i end up not under the trans when I pull the trans jack that final bit into position.. it will mate right into the pilot if you get the angles just right.. then you can start the top few bolts from up above.. remove your test bolts.. and bolt in the rest..



since the converter is studded.. I pulled the jack in till the converter studs hit the surface of the flexplate and pulled a tad bit of pressure.. then used a mallot and sacrewdriver to turn the converter till one or 2 of the studs popped into place.. the rest will line up because you asre riding on the long bolts for the mounts..

remember to use Loctite on your converter nuts and flexplate / flywheel to crank bolts.. measuring the front driveshaft is easy... you mount up the yoke and install the front shaft U-joint on the trans yoke and snug it into position.. leave the 2nd driveshaft splines out.. place the front driveshaft on a jackstand.. rotate the carrier bearing to its position and then measure fro mthe center of adjustable slides on the carrier bearing to the center of the hole in the bracket.. thats how much you need to have cut out of the driveshaft... center is important and make sure the rubber surround on the carriuer is seated straight and in its middle position. . that way you still have about 3/8 - 1/2 inch to play with when installing if you got a measurement slightly wrong..



cooling lines should be #12 ORB instead of #10 like the 545 is.. grainger / parker/ and others sell adapters..



hope this helps a little..



be safe a 643 is a heavy bugger
-Christopher

 

[Skalbus]

Christopher, Thanks for all the tips. I saved them to a word doc for future reference.

I do have air brakes so no drum to worry about.
The bolt with the cut off heads is a great idea. I've done that before on a small vehicle trans but didn't even think about it since it's been so long ago. Thanks for the reminder.

I here ya on the weight of the trans. I won't be getting in it's way. I don't have a trans specific jack but a do have a motorcycle jack and three floor jacks so hopefully I'll be able to make those work.

Now I just gotta set aside a weekend and stock up on the ibuprofen.

It's been way to hot here in S.Cal the last couple weeks to work all day. Last week we hit 122 a couple days in a row.
Thanks for all the help, Eric.