My new MC-5C - Allison swap thread!

bevans6 · October 11, 2016, 10:02:33 AM

The supplier I am talking to has a off-the-shelf SAE-1 to SAE-2 adaptor ring that has a built in 1" offset spacer. Is that what I am looking for, or would I need an additional spacer ring? I guess I won't be able to tell for sure unless I also have the flex plate and the crankshaft adaptor, then I could expect to be able to measure from the bellhousing flange to the flex plate and know how deep I need to be at.

Clifford or anyone, do you have or know where I might find a flex place with SAE-1 ring gear and the crank flange adaptor to suit?

Brian

bevans6 · October 15, 2016, 12:15:36 PM

Well, an update of sorts. After delays from not being able to get the driveshaft out, a semi-hurricane and around 30 hours of blackout/no power over two days, and me just plain working slow and taking a day or two off, I pulled the engine out this afternoon. I used a pallet truck and built a wooden framework to pick up the rear bellhousing where the engine mounts bolt on, and the front lip of the engine where the oil pan bolts on. Tomorrow I'll take the transmission off and have a look-see at the clutch to see if I can find anything obvious wrong with it. I suspect the friction facings on the discs are what is causing the dragging. I am off to Fredericton, New Brunswick (a four hour drive one-way) to pick up my new MT-647 on Thursday next week. My new flex plate is on order, they are installing a short yoke instead of the flange plate, they found a steel SAE 2 to SAE 1 adaptor, and I'll be able to start measuring and fussing to figure out if I need a spacer and what crank adaptor I'll have to make. After that I can trial fit it so I can measure so they can shorten and rebuild my driveshaft. Then I have to measure for a modulator cable and start to figure out a shifter, get a transmission cooler and filter, and all the stuff that nickle and dimes you to death. Anyone has parts to offer, I am happy to try to make a deal!

Brian

lostagain · October 15, 2016, 12:52:35 PM

Starting fresh like you are with an automatic transmission, I would look for a Stone Bennett control pad up front to activate electric or pneumatic solenoids at the transmission. A cable shifter is fine if well lubricated, but, at least in my bus, the shift tower is in the way of getting in and out of the seat. It would be better on the left side if you go with a cable system. And I would cool the transmission with its own dedicated cooler, to avoid putting heat into the engine coolant. Although it sounds like you already got that figured out.

Have fun.

JC

Dave5Cs · October 15, 2016, 01:02:42 PM

JC agree with you as far as it always is in the way on the right or as we say PITA if you know what I mean.

Dave5Cs

bevans6 · October 15, 2016, 01:44:02 PM

Has anyone ever adapted the manual shift lever as a shifter? I hate to throw away stuff that's good, and there it is... I was thinking of hooking a push/pull cable up to the shift rod in the engine bay. Probably a stupid idea, but there you go. Initial examination shows no cracks in anything anywhere, my bus has a cross-member which earlier buses did not and there may be other reinforcements. I am worried about transmission clearance over the cross-member though.

Brian

chessie4905 · October 15, 2016, 03:56:19 PM

You could probably get a shifter assy from city bus junk yard. Morse makes cables that will outlast your coach and almost friction free. You will need to accurately measure.Oh, and also check with school bus junk yard. They've been using automatics in many of them for some time. Some shifters are on the left of driver.

Dave5Cs · October 15, 2016, 06:33:57 PM

Would it be possible to get a longer cable and then move the shifter to the other side and have it reach?
Dave5Cs

Ed Hackenbruch · October 15, 2016, 06:45:11 PM

Brian, the PO used the original lever and rod on my 5A when he put in the 644.

luvrbus · October 15, 2016, 07:05:10 PM

LOL the dash switch for a Stone/Bennet is the way to go I have used the Stone for over 20 years.
Brian I am trying to find you a couple of lock up valves to send in your care package,you are not going to like the 647 just locking up in 3rd and 4th gear it makes the Jake even more useless

eagle19952 · October 15, 2016, 07:29:19 PM

my Allison has the shift lever is on the left. i like it.
Probably a good reason not too

luvrbus · October 16, 2016, 05:34:19 AM

I have moved a couple to the left side, people with seats that swivel prefer it on the left it cleans the floor area up

bevans6 · October 16, 2016, 08:20:11 AM

I took the transmission off this morning, and strongly suspect spline wear as the reason for the dragging clutch. Visible wear where the discs ride against the spline, the wear area is .015" smaller than the unworn section of spline. Everything else looked reasonably fresh, finger height was good, disc thickness was .420", visible grinding marks on the pressure plate from when it was blanchard ground, and the other friction surfaces looked clean. Just a tiny bit of bluing from heat in a few small sections. I had used grease on the splines, now not sure if that was a bad idea or not.

Brian

eagle19952 · October 16, 2016, 08:27:47 AM

i have often suspected metal fatigue/age contributes to splines "off set" and wear.
just a fact of life.

are you still going to go with the allison ?

bevans6 · October 16, 2016, 09:32:00 AM

Yep. My knees are going, so sometimes I can't drive the clutch for very long. Getting an new input shaft for a Spicer is a bit of a long shot. I have another used input shaft but it was outside for a year or so and is a bit corroded.

Brian

bevans6 · October 17, 2016, 10:57:20 AM

Well, even working as slow as I do (I tend to mosey on out around 10:30 am, lunch from 12 - 2 pm, and nap time at 4 pm...

) I pulled the engine and split the tranny off on the weekend. Number one trick, remembered from troubles last time, was to level the bus side to side and front to rear so the engine cradle was as level and plumb as possible so that when I picked up the engine it cleared the rails evenly. Pulled it out with little drama, pulled the transmission off, clutch and flywheel. Looks like input shaft spline wear is the most likely culprit, there is visible wear on the drive side of the splines from the clutch discs. All the rest of the clutch looks almost new, there are still blanchard grind marks on the pressure plate, the other friction surfaces look perfect, and the discs only have .020" wear from new spec. I put new throw-out bearing and pilot bearing last time, so they have less than 10K on them. Anyway, I know how you all like pictures...

If you look closely at the picture of my shop, you can see her looking out of the window on the right. I wanted to give her a window so she wouldn't get bored this winter...

Brian