Reply
 
Thread Tools Display Modes
 
Old 11-16-2017, 04:20 PM   #1
New Member
 
Join Date: Aug 2017
Location: Cincinnati, OH
Posts: 8
Year: 1997
Coachwork: AmTran
Chassis: International
Engine: DT466
Rated Cap: 78
Swapping an MT643 for a manual

Hi all,

This is my first time posting in here, so here goes nothing.

Me and a few friends from college stumbled upon skoolies and decided to give it a shot and convert one for a national parks trip we plan to do after graduation. We looked for a bit and pulled the trigger on a '97 AmTram Genesis with a DT466 paired to an Allison MT643. Great combo right? Well it would be if the transmission were functioning properly.

It seems that the lock up clutch in the torque converter isn't locking up, so we only ever get to 3rd gear, unlocked. From what I've read, this will essentially spell death for the transmission if operated like that long term, from elevated temps. And we only ever get up to ~45mph, with much higher RPMs than I feel comfortable maintaining for too long.

So from my understanding, we replace the torque converter. Doesn't sound like too difficult a job (I have access to a diesel shop with a lift and heavy duty equipment), but I can't find a used one or the proper new one anywhere online. Quotes to get the work done in nearby shops are around $2000 for parts and labor.

We're not willing to bite the bullet on $2000 just yet, so I started looking into replacing the transmission altogether. For another MT643, I've seen a few in the $900 range. But what I'd really like to do is replace it with a manual, such as an Eaton Fuller T14607. I found a truck parts store that sells refurbished units for ~$400, just for the transmission itself (no shift linkage, no nothing). If i'm not mistaken, both the DT466 and T14607 have an SAE #2 bolt pattern so they'd match up just fine.

So what I'd like some guidance on is whether or not I should try to keep the MT643 and if there are any tips/tricks out there to fix it before I have to take it to the shop; or if I should go ahead and invest the time and money swapping the transmission altogether. I'd like the reliability and additional control with a manual (and the extra gears would be nice if we decide to swap out the rear end gearing), but at the same time if there's an easy repair out there that I'm overlooking I'd like to explore that before diving into an entire trans swap.

If we do go that route, there are a bunch of questions I still have:
How do I find a clutch/pressure plate that fits the application between the trans and DT466?
How do I deal with having shift linkage further back than ideal (since its a flat nose bus)?
What's the best way to go about mounting the clutch pedal?
What's the best option for a speedo if I swap the trans?
What do I do for transmission mounts on a new unit?

The trip isn't until the summer of 2019, so we've got a bit of time to figure it out and having a group of people to pitch in on repair money is nice too.

Any advice you can give will be greatly appreciated!

Thanks in advance!
cincycrew is offline   Reply With Quote
Old 11-16-2017, 04:44 PM   #2
Skoolie
 
bigskypc50's Avatar
 
Join Date: Dec 2016
Location: Anaconda,MT
Posts: 148
Year: 1995
Coachwork: Amtran
Chassis: International
Engine: DT466 Turbo
Rated Cap: 70
The MT643 is a pretty durable and strong transmission. I would be surprised if it really needs to be replaced. I am going to assume you have checked the fluid level etc.

When I first drove my bus I was sure the trans was messed up (and walked away from the deal), it feels like it shifts though like 6 gears or it was slipping really bad when it really is just going in and out of lockup, what kind of RPMs are getting at 45MPH? Most will not shift until 2000-2100RPM. I think I have a video of my trans let me know if that would be helpful to you. It should something like this 1-2 then 2-3 then it will drop RPM into lockup then it will unlock shift to 3-4 and re lock up.

How many miles are on this bus?

If the trans is really bad, I honestly think about scrapping the bus if you don't want another MT643 in there (I would totally keep one in there), to add a manual to something like that would takes lots of work money and trouble, cool to see in the end but not easy by any means.
__________________
My Skoolie Project:
https://www.facebook.com/skylinerskoolie
bigskypc50 is offline   Reply With Quote
Old 11-16-2017, 06:15 PM   #3
New Member
 
Join Date: Aug 2017
Location: Cincinnati, OH
Posts: 8
Year: 1997
Coachwork: AmTran
Chassis: International
Engine: DT466
Rated Cap: 78
Yup, fluid level is good. The bus has 200k+ on it. The engine was swapped for an overhauled unit around 20k ago, not sure if the trans went with it or this is the original.

I want to say 2300-2500rpm, and it didn't seem like it was going through multiple gear ranges. It went through 2 shifts, then held the high rpm and stayed there. But I didn't know it would unlock again, then go to 4th locked.
How long does it take it to lock up? We've been driving it in 20min intervals and I get up to 45mph, then coast and the rpms drop back down to idle. If the lock up were working, it should stay at the rpm slowly lower with vehicle speed, right?

Is it possible that because the bus only saw occasional use from the previous owner that the valve body is gunked up and needs to be driven hard to dissolve any deposits?
cincycrew is offline   Reply With Quote
Old 11-16-2017, 06:57 PM   #4
Skoolie
 
Join Date: Aug 2016
Location: Kansas
Posts: 217
Year: 1995
Coachwork: Thomas
Engine: 8.3 Cummins, 643
A new filter and fluid may help, I'm no mechanic but just changing fluid has fixed issues for me in the past. In the end even if the 643 needs replaced it will probably cost less then a swap even if you can get a great deal on the manual transmission. If you really want a manual finding a donor vehicle with all the patts needed is one way to go about it if one can be had cheap enough
Jacob is offline   Reply With Quote
Old 11-16-2017, 07:07 PM   #5
Skoolie
 
bigskypc50's Avatar
 
Join Date: Dec 2016
Location: Anaconda,MT
Posts: 148
Year: 1995
Coachwork: Amtran
Chassis: International
Engine: DT466 Turbo
Rated Cap: 70
It should lock up right away, after the shift point below is a video of mine. The DT466 won't redline until 2800RPM but if your hitting 2500 and it's not shifting there is something up. I don't think it's gummed up unless the fluid is dirty or burnt, check the fluid and see if it nice and clean bight red and clear and not smelling burnt?

Check out this site also TransDiesel of Cental Florida - Servicing Allison transmissions and parts

My MT643 shifting up to 3rd at 25 MPH: https://youtu.be/9bGbGlLV3PI

If it was mine I would take it back out on the highway before anything more and drive up to 2700RPM hold here for a few mins and see if it wants to shift. I would try some lubegurad (red bottle) also if my highway drive was not eventful. But get some more advice on the lubeguard don't know if it's good or bad for big truck stuff.

Someone with more experience will chime in, but ya start with a fluid change before going to a shop.
__________________
My Skoolie Project:
https://www.facebook.com/skylinerskoolie
bigskypc50 is offline   Reply With Quote
Old 11-16-2017, 07:27 PM   #6
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 12,176
Year: 1992
Coachwork: Ward/AmTran
Chassis: International
Engine: dt466
Rated Cap: 78
My DT466 redlines at 2600.
__________________
.
Roll Your Own Build Thread
EastCoastCB is offline   Reply With Quote
Old 11-16-2017, 07:51 PM   #7
Skoolie
 
Jolly Roger bus 223's Avatar
 
Join Date: Sep 2017
Location: Swansboro,NC
Posts: 197
Year: 86
Coachwork: Thomas
Chassis: Ford B700
Engine: 8.2
Rated Cap: 60 bodies
With your time line and without a donor vehicle to get everything you need your only option is a filter, fluid change and if that don't work then find another one and send me your old one to replace my 545.
Trust me?
Working on replacing my old ford auto tranny with a manual tranny and it wasn't built for it? Then you have to build it for it????
Time? Money? Put it in,mark it,take it out, make what you need! Put in again and see if it works.
Auto to manual is not hard if you have a donor?
But if you have to guess at everything that could cost you in excess of 2000$ and a lot of time?
Rebuild what you have because you have because it is an exact fit and you know the exact condition of what you have transmission wise anyway?
Jolly Roger bus 223 is offline   Reply With Quote
Old 11-16-2017, 08:17 PM   #8
Bus Crazy
 
Elliot Naess's Avatar
 
Join Date: Oct 2005
Location: Clearlake, Northern California
Posts: 2,116
Year: 1992
Coachwork: Blue Bird
Chassis: TC-2000 Frt Eng, Tranny:MT643
Engine: 5,9 Cummins
Rated Cap: 84
I am interested in this swap also, perhaps largely because I drove sticks for a living and simply do not like automatics at all.

You may want to check your modulator/kick-down cable. This is only a theory, but your MT643 might be in kick-down all the time.
__________________
Elliot
Millicent The Bus - roof raised two feet, toy-hauler tailgate.
http://www.skoolie.net/forums/f11/th...gate-1564.html
Elliot Naess is offline   Reply With Quote
Old 11-16-2017, 09:14 PM   #9
Skoolie
 
Join Date: Mar 2011
Location: Port angeles, Wa
Posts: 186
Year: 90
Coachwork: bluebird conventional
Chassis: international
Engine: dt466
Rated Cap: 72
First off, just changing the converter most likely won't solve your problem. The locating pins in the drive cover break off, the clutch plate blows apart and you have metal everywhere. Oil goes from the converter to the rest of the hydraulics and spreads the metals. Get the entire trans gone thru or get a good used one.
If you decide to go standard, I may be able to help. I have a spicer 5 speed in mine and going to an mt643.
bluebird90 is online now   Reply With Quote
Old 11-16-2017, 09:18 PM   #10
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 12,176
Year: 1992
Coachwork: Ward/AmTran
Chassis: International
Engine: dt466
Rated Cap: 78
Quote:
Originally Posted by bluebird90 View Post
First off, just changing the converter most likely won't solve your problem. The locating pins in the drive cover break off, the clutch plate blows apart and you have metal everywhere. Oil goes from the converter to the rest of the hydraulics and spreads the metals. Get the entire trans gone thru or get a good used one.
If you decide to go standard, I may be able to help. I have a spicer 5 speed in mine and going to an mt643.
I'm not a fan of the Spicer 5 speed. You're making the right move, imo.
__________________
.
Roll Your Own Build Thread
EastCoastCB is offline   Reply With Quote
Reply

Tags
amtran genesis, dt466, lock up clutch, mt643, torque converter

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


» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 10:58 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.